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philips tv 29pt5642 / 55 chassis L04, main source problems
Smart TV RCA 40
Smart TV RCA 40
4 Soluciones
14 Reparaciones
23
hace 5 años
hace 5 años
Good evening friends of the forum, I am new to this chat medium, through this you are sent a cordial greeting from San Cristóbal - Venezuela. I need help to repair a Philips TV model 29pt5642 / 55 chassis L04 which has me stressed ... . I tell you: the TV arrived with failure to turn on and when checking the stambay source because the voltages of 3 volt and 6 volt were present in the circuit, that is, this source was OK. Later I went to directly check the TSH ( 7405) BU4508DX and it was short, then the mosfet (7512) of the oscillating stage was checked and this component leaked in its measurement. As a start to the measurements, the change of the named mosfet was made and measurements were made of the main source at its output + B but without placing the TSH in its circuit, all this in order to verify the total operation of the main source Working in isolation from the rest of the components, the circuit was opened by separating coil 5552 (according to the electrical plan). Performed this step, I proceeded to connect the power cable of the TV and measure + B, the multimeter reached a value of 70 volt max at this point (performed on the filter terminals (2552) of 100m - 160volt) and almost immediately this value fell to 0 volt and the source was heard to stop oscillating, this part must be normal, since, the feedback stage of the opto-coupler receives a pulse called Stdby_Con from pin 15 of IC Hercules which sends disable the main source once it is connected to the power grid or if for another reason it detects any anomaly in the other components or sources that make up all stages of the TV. To prevent this source from being disabled and verify if it was functioning correctly, this Stdby_Con pulse was isolated, a bridge (wire) was lifted that connects them directly to the Hercules IC and immediately the cable was connected again to the mains and They repeated the measurement steps of + B without load and with load (for this a 60 watt bulb was installed on the terminals of filter 2552), the multimeter at this time marked a maximum 110 volt value (the typical value of + B at this point it must be 130 volt according to its plane), the + Vaudio and - Vaudio sources were also measured (according to the plan they should be: +16 v and - 16 v) but the multimeter measured in these sources low values to normal + Vaudio in + 9 volt and in - Vaudio reached a value of -14 volt. According to the values detected of + Vaudio and - Vaudio, these sources were isolated (removing other components and bridges) from the rest of the audio output amplifier circuit of this TV in order to rule out overloads in these sources as a consequence of present anomalies, the values were measured again but the difference was not much and the + B remained at 110 volt + Vaudio at + 9 volt (it should be noted that this source is used as an opto-coupler feed in the feedback stage of the main source. indicated that the source already mentioned is not stable or is not oscillating in a normal way.Then more measurements were made in + B but at this point the pulse (3.3 volt) Stdby_Con from pin 15 of IC Hercules was connected again, for this the bridge that had been desolded in the circuit was connected but at this moment we find a surprise and that is that now said pulse or source of 3.3 volt from the Hercules is not found now and now the main source is apparently oscillating continuously with the low values already described in + B and V audio and now the source once the cable is connected to the network begins to emit a noise (tic tic tic) in the tranf choper, which is abnormal ... Please if someone could help me, I would really appreciate it ... thanks
Here is the diagram of my tv, chassis L04: http://www.electronica-pt.com/index.php/component/option,com_remository/Itemid,34/func,startdown/id,1024 /
Thanks Felipe Antonio for the probe diagram, I will try to locate components and assemble the circuit .... a question ... the positive and negative output of this diagram goes directly to the multimeter voltage meter ?? ... What voltage should it measure to verify that it is in the correct oscillation values? ... as I had already said at the beginning because the TSH (horizontal output) was achieved shortly .... I already have a new one but the measurements have been made without this TSH being present in the circuit and additional measurements have been made with an onn focus load of 60 watt at output + B
Thanks to fellow Felipe Antonio for his concern in helping me .... on the other hand because I am not sure what you say with the paragraph "" "Of the Second Option. - If you have a transformer like the modular ones) some have A 30 / 40VAC output in the secondary, to the secondary of this is that it connects the plug.The probe connects it to the drain and is the reference that you will have to know if the circuit oscillates.- There is even a post, where removing the optocoupler and by connecting a 100k control with a resistance of 10k ohms, at one end, moving the control, the primary (hot) source has to oscillate, therefore there has to be a "record" of voltage in the secondary. "" ". ..... I understand that what you call "plug" is the input power plug of the equipment ??? .... I can tell you that during the measurements made another bulb was placed in series to the cable (plug) that feeds the TV at the input that has a value of 115 VAc approx .... what values must be obtained in VDC taken with the probe that indicates me connected between D and earth to know that the input circuit is oscillating in perfect conditions ??? .... so far I am not sure if This source that is commanded by the Ic TEA1506T is oscillating properly but it is possible to hear (tic tic tic noise) in the choper and this implies that if there is oscillation ..... or am I wrong? .He should remember that I have the + B and + Vaudio and -Vaudio output isolated from the rest of the circuit ..... I would appreciate your next contributions to my case ... thanks ... if you have any graph or photo of the location of the probe I thank you
Good morning friend Felipe Antonio! thank you for your contributions in my case .... sorry for the delay in responding .... for this area you are removing the electric current with an average of 5 hours in a row .... well I tell you that I built the probe circuit that you sent but with 1n4007 diodes and filters of 100 nf but 400 volt that I got .... a question .. with these values measurements can be made on the mosfet drain leg of the main source or the values of the components are very Low? ..... What is the difference with the voltages and frequencies that are handled at this stage and those handled by the TSH driver .... I am clear that we must first recover the main source but as additional knowledge as you I ask about that part of the electrical circuit ...... another question I have is that if for me to make these measurements in the mosfet I must necessarily place the dimer with focus or the 30 VAC transformer (in output) in the supply AC TV input, I ask because you You tell me that you have to inject the AC input with lower voltage values to be able to measure in the mosfet and see its behavior ........ because it seems to me that when injecting voltage values below 90 VAC at the entrance of the TV because the team would be working forced and I tell you by the work characteristics (given by the manufacturer) of the integrated and other components that make up its circuit .... thanks
Good afternoon companion Felipe A., indeed if you write on the side of just commenting because there seems to be a limit of characters .... in my case I am the one who asked the question to the forum because I give it where is the main paragraph of the question and I give the pencil figure that means to edit the question and every change of the question should reach everyone in the forum who has answered my question to want to contribute their suggestions (at least that was what I understood in the rules)
On the other hand, I forgot to say that I had already tested my probe with the AC input voltage of my equipment (taken from the mains) and when I made the measurements, the AC input voltage marked a multimeter value of 124 VAC (in VAC scale), if I multiply that value by 1.41 it gives me a value of 174.84 VAC and if I multiply that value by 2 it gives me a total value of 349.68 VAC that would be the same VPP as I understand you, after obtaining this mathematical calculation I directed to place the probe directly to the terminals of the VAC input jack and place my multimeter is the scale of VDC connected to the output of the probe as indicated by the diagram and my measured value is 344 VDC that I imagine that would they be the approximate value in measurement of what the same instrument on the VAC scale measured me ??? ... that I could see that this voltage is as large as what my 100 nf filters that I placed should be supporting, since the they indicate 400 v
The capacitor values change the value due to the frequency to be measured ?? ... are different oscillation frequencies?
"" "I don't know who he refers to with the" expert "but I am not.- all the probes we have made, we take as a base a voltage of 50 / 80VAC.- from this we get the percentage. The reason why the Oscilloscope that we have only measures 400vpp.- I think that with the values it has, it is possible to measure and keep a record. "" "... Well, don't misunderstand me by having written" expert "... it was just with a comment or purely positive praise, since, in that part I am in "diapers" or I don't know much; and although I know a little the theory of these capacitors because it is not the same to apply it in reality and that is why I come to you for help and at the same time I ask each question in order to clarify my doubts and learn well about the subject, Regarding his years of experience in this part of switched sources of TVs and I really thank him for every new contribution you give me .... I apologize for any misunderstanding in my sentences ... I really would like to rule out that TEA1506T is working well or is failing to not change the component to change, it is to know that this IC is SMD (superficial) and is more delicate in just removing it unlike the others in the circuit ... my experience is based on other types of equipment such as telecommunications and some of electromedicine and some years of experience in TVs, but I think that the same years of experience that you have in TVs I should have to be isolated from playing the last TV many years ago , that is I'm like a new student again ... thanks again
I still don't understand why there is no voltage in VDC there at the output with 100w focus, can it be measured with the probe there at the output to see if there is an alternating component or VPP generated? because during this process the tea1506t is heard to work normally and after removing the focus because the IC seems to be disabled by some protection or by the feedback .... thanks for any additional input .... it seems that I am advancing but as if I stop. .... I'm already as something outstretched with this fault but I want to know that I could fix it
As additional information I can tell you that during these measurements I have a series of protection for the TV with a focus of 60 W and the VAC input of the TV
.... you commented: ".... the 100w focus will connect it to the vca input even if it has another focus it can be placed in parallel with that of 100w.- we will remove the flylbck and the hot and check if it has b + , if we do not have b +, we will remove the chopper and apply vcd on pin 17, about 50vcd, this in order to be sure that the "channel" of b + until the flybck pin does not have any short or overconsumption. If you do not have short we apply vcd to pin 13 and pin 10 of the chopper, this to check the voltje and 12vcd consumption are sufficient. "" "...... excuse me: because it is necessary to place two 100w bulbs in parallel to the VAC input ??? ... I remind you that it is a series of protection that I have connected to the TV input (the bulb is not lit, and according to what I understand this indicates that you are not seeing short in the input, however I put it as a precaution) ... I apologize again: I remind you that although I have not removed the flyback of the TV because at all times of the measurements re Once the + B output was isolated from the rest of the circuit, that is to say that the + b is ONLY present in the stage of regulation of the main source, since it disconnects the coil 5552 which is the one that goes directly to the flyback (the hot one is also outside the circuit) as seen in the plane of this tv ... what I understand from this test that you mention to remove the choper and place 50VDC in the place where pin 17 of this choper was because I imagine it is to discard that there is no short in another component of these stage, although with the coil 5552 out of the circuit because what is left are the components of the regulation stage in conjunction with the optocoupler .... correct me if so what I understood you .. .Thank you
Good morning companion Felipe A.! I appreciate all your contributions so far in my case .... I take this opportunity to send a cordial greeting to mr. Jose Antonio for joining in contributions to achieve the solution of my TV, in fact I was already measuring the output voltage of the auxiliary winding (legs 2 and 3 of the choper), for this I could disconnect the cathode leg of the diode 6511 (according to plan) and I soldered another capacitor (identical to 2511 VDC of the IC) and connect it to earth, all this to be able to measure alternately if voltage was actually being generated in that winding once the TEA IC manages to start (initially polarized with voltage which comes from the stambay source stage in capacitor 2532 and diode 6512), at this point and under the conditions of the circuit already mentioned it is possible to appreciate that the IC continues its operation in the same way as before, that is, with the voltages dropped in the output and without voltage in leg 3 of the optocoupler, but with the novelty that it was possible to register a voltage in my tester of approximately 8.5 VDC in the positive of the capacitor placed to the diode 6511. Here it can be seen that this voltage is s too low for this source (auxiliary winding) to manage the IC and inject more current into the circuit, since as seen in the plane as this voltage should have a value of at least 15.6 VDC (greater than the 9.5 VDC that comes from starting from the stambay stage) as can be seen in leg 4 of the opto on the tv plan. According to my knowledge about this plane, I can draw conclusions that since there is no voltage greater than that measured and close to 15.6 VDC since the IC would be starting and emitting its first pulse at the output but immediately it would be disabling since its vcc voltage drops but immediately the IC would be feeding again from the stambay stage (9.5vdc) and would do the same thing again, that is to say it emits its first pulse and due at the voltage of the auxiliary winding it would be disabling again, a circle of on and off of the IC is created and therefore not enough pulses are generated to be able to maintain the output voltages of this was nte .... thanks
2.308
hace 5 años
Mr. Luis.- you need to test the probe. (vca by 1.41 by 2 equal to vpp) .- With the probe you can measure the vpp in the driver's collector, hot base, heater, the signal in the cathodes of the kinescope, and check the flyback whenever the voltage on the pin b + of the flyback does not exceed 50vcd. Look at the picture I sent you of the probe (rustic) to measure in the primary sources of TV screens. Here the value of the diodes changes and the capacitors are at 2kv. These values have to be used because we use 60 / 110VAC. as you can see in the photo the vpp is 403vpp is an lg screen.
2.308
hace 5 años
We remove the flybck and the hot (already by custom) we place the focus of the b + on the ground, and so we work only with the source. You need to make the discharge probe (here we discharge because we have three) .- Now look at the diagram: the drain has 295v. between 1.41 are 209v between 2 are 104vca. It means that the 295 will have them when it is oscillating. if you place your multimeter and only measure 155 / 160vcd it means that it is not oscillating. if you multiply 155 by 2 by 1.41 the vpp will reach 437vpp. voltage that our oscilloscope cannot measure, and you can see that the multimeter marks 403vpp.
2.308
hace 5 años
What he will have to teach me is: how does he have so much space to write. I comment on it and there comes a time that no longer leaves more space to continue. .- summary. 1.- make the discharge probe. 2.- having the high one you can use all the vca of the line. 3.- if you want to make measurements with voltage variations you will have to use the dimer or the transformer. Before placing the probe, the high one or the flyback one, you have to test them by connecting them to the VCA socket. make a rule of three to check the deviation percentage. Regards.
2.308
hace 5 años
Mr. Luis. The accounts are very good! .- but the probe does not have filters; it carries capacitors.- now if at 124vca the vpp is 349 and 349 is one hundred percent; if you have 344vpp your probe will be 98 percent effective. We cannot use it in the primary source because the diodes can withstand the vcd, but not the peak voltage. That is why you need to make one with diodes and capacitors marked in the diagram and like those in the photo, because basically the vpp will be about 400vpp minimum. We need the 2kV diodes and capacitors, so you can place the probe to the normal VCA. Regards.
2.308
hace 5 años
On the other hand, the vca of the line is a sine wave. The drain waveform and the chopper secondary waveform are not sinusoidal. nor are the waveform of the driver collector, hot base and heater (filament). Regards.
23
hace 5 años
ok thank you ... you are right about the word condenser .... those are the ones that I put to my circuit ... of the so-called "ceramics" in this area and they are up to 400 v and so I understood you well no they serve me for the input .... now I ask what is the difference with respect to the diodes of one diagram and the other ... and if the "high" probe diagram as you say has more capacity in terms of diode and capacitor voltage because if this is built only because I think it should be used to measure in both stages ??? ... bone in the mosfet and the TSH driver .. I think
2.308
hace 5 años
Technically you are right, the high one would have to serve as much as the "low" .- The "low" was done when we did not have an oscilloscope, and it was the lack of this that leads us to take a course in applied mathematics. Note that the diodes that the hot carries in the collector and yoke are not 4007, they are special. in terms of voltage, amperage, and fast and ultra fast signal recovery. That is why we had to register and the one we already had. I am going to send you an oscillator diagram that we use so as not to depend on the oscillation of the jungle, this and an external source is what we use
2.308
hace 5 años
To try the flyback. -the diodes of the "high" probe with the "low" probe compared to the datasheet. It is too much difference. -I personally do not dare to use the low probe instead of the high one. especially since the probe connected it to the fluke meter. The oscilloscope and the fluke are a priority. (more than my health) .- greetings.
23
hace 5 años
ok I understand! ... thanks ... in summary the probe that you call "high" is the one that is constituted with 2 kv capacitors and this is the necessary and recommended to measure in the mosfet of the main source and as you I also understood this same probe for being of high values in its components because it can also be used for the other stages that you mention including the TSH driver without problems
23
hace 5 años
Good afternoon friend Felipe A., you are very grateful for all your contributions in my case .... I am resuming the repair of this TV since I was absent and busy working in another area direct to the TVs, I also had problems with the internet. .... well I tell you that it has been a bit difficult to get exactly the values of the high frequency probe capacitors, got damper byw diodes and 1.2kv capacitors of 0.005 microsf (5 nf), 0.047 microsf (472J or 4.7 nf) and one of 10.7 nf (6.8nf + 3.9nf), but I could only test with the 124 VAC network at the input
23
hace 5 años
and then I measured the VAC input with the probe and the VDC scale tester and the measurement I obtained was 250 VDC (VPP) and according to the calculations made with 124 VAC at the input as it should give a value of 349.68 VPP and at to calculate its tolerance of pressure because the probe gives me a value of 71.49% and I don't know if it is enough to be able to measure with the probe in a reliable way in the mosfet, I don't know if it is the best way to be able to test this high frequency probe, since, the measurements I am making to the network of 124 VAC at 60 Hz and the frequency of the oscillating TEA 1506T varies in a range 25-175 KHz
23
hace 5 años
on the other hand because I saw on the internet a circuit composed of a 10 nf / 1.6kv capacitor in series with a 10k resistor and a NEON bulb that they use to only verify if the IC is oscillating ... I placed this circuit in the mosfet and the other side bolts and turned on the TV and the NEON starts to blink (turn on and off) and achieve the blink count and reach to count 120 blinks in a time of 1 min, but in my opinion this frequency is too slow for the good operation of the source ... I was measuring the voltage coming out of the optocoupler leg 3 according to the plane
23
hace 5 años
according to the plan of this tv because in leg 3 of this optocoupler there must be 5 v (I imagine VDC) and in leg 4 (15.6 v), but I can only measure a value of 10.5 with tester in VDC in leg 4 v but in leg 3 of it because I do not measure anything, change optocoupler and stay the same ,; I already got a new TEA1506t but I did not want to change to verify if the fault is not another ... I could isolate the leg 6 cntrl (oscillator) to discard short in this leg and measure voltage in optocoupler but there was no value in leg 3 but the integrated stopped oscillating (the little that oscillated)
23
hace 5 años
when I put back connection to leg 6 (oscillator cntrl) because it oscillates again with the low values of always on output and same frequency measured with the NEON ... I don't know if there is another way to simulate the optocoupler and I don't know if It is the integrated TEAT that is actually failing ... according to this IC's datasheet because in leg 6 (cntrl) there must be a value between 1-1.5 v to oscillate at 25 kHz or 175 kHz .... thanks for what can you give me ...
2.308
hace 5 años
Mr. Luis. - All the calculations you have made are excellent. (It shows that he likes math) .- 1 .- the capacitor, neon and resistance are good, because they indicate if you have oscillation, and only serve as a reference. 2.- having 250vpp is 71 percent, it is acceptable.- there are peer meters that when doing the probe only have 50 percent. This is because of not only the diodes, but also the voltmeter. After many tests and data search, we read and verify that it is the meter. I have a fluke. and this is the only meter that detects ......
2.308
hace 5 años
... and measures a square, rectangular wave etc. That is why I have a higher percentage in measurement. Increase the 80VAC voltage and take your VCD and also check the Vpp of the probe. the value of vpp in the probe should oscillate briefly, but when giving power it has to remain stable. The fact is that having oscillation this should be reflected in some voltage in the secondary.
2.308
hace 5 años
At night, I will look for the diagram and we will see how to check if it has any shorts in the secondary ones, for this we use a source with lm 317 and we usually remove the chopper. To remove the optocoupler, just remove it, and place a LED, on the other side connect a 100k ohms control with a resistance of 10k ohms, I have seen colleagues who have done it, even here in the Forum there is a post on how to do it, in I have never personally had the opportunity to see how it works. regards
23
hace 5 años
ok thank you! .. you are right about the math ... well he is the expert in this type of probe ... but here we must remember that I raised the low frequency probe with 100nf capacitors and 1n4007 diodes and the value measured in tester in VDC was 344 vpp, that is to say it had approx 98% accuracy and the way of testing seems logical because the input frequency is 6 Hz ... now to measure the other high-frequency zone is not Should you take into account that you should measure reference values that are in a high frequency and high voltage ??? I say it by the capacitive reactance formula
23
hace 5 años
Capacitive reactance is the resistance offered by the capacitor to the passage of alternating current Xc = 1 / (2.pi.FC), both the variation of the frequency and the value of the capacitor intervene in the final value of the capacitive reactance of the circuit and therefore in the final value of the peak peak voltage measurement ..... what you tell me about testing the high frequency probe by lowering input voltage because I respect it even though I don't understand it yet, because it seems more logical as to test the low frequency probe and use it in the mosfet with low values that do not damage the measurement tester.
23
hace 5 años
I must also remember that I am with the isolated source in secondary, I have a + b, + Vaudio and -Vaudio completely isolated from the rest of the circuit and the stambay pulse I have removed so that the main source and power is not disabled make measurements so you could not do the test of trying to turn on the TV to find the stability of the oscillator, since I also have the TSH removed ... thanks
2.308
hace 5 años
I do not know who refers to the "expert" but I am not.- all the probes we have made, we take as a base a voltage of 50 / 80VAC.- from this we get the percentage. the reason why the oscilloscope we have only measures 400vpp.- I think that with the values it has, it is possible to measure and keep a record.
2.308
hace 5 años
the low probe, we will discard it even by placing the primary source at low voltage, the reason is that the capacitors and the diodes will not support the high current that is generated in an instant. The fact of connecting at low voltage is because the oscillator is linear, we will check how much minimum voltage it oscillates and how much it has of vpp in those conditions, when increasing the input voltage it has to respond the oscillation, it also gives us to measure the voltage drops on the pins
23
hace 5 años
good afternoon felipe how are you? .. I tell you that I just changed the tea1506t and when you give the button to turn on tv you hear that the frequency of oscillation increases (tic tic tic tic sound) and I put a light bulb of 100 watts and the condenser output but when measuring the voltage there because the tester marks 0v if I remove the charging bulb, the tester starts measuring a voltage that begins to increase as it was before changing IC but now it is possible to hear that the IC is disabled and stops oscillating by complete, that is, apparently the change of IC because if it was necessary but I still do not understand
2.308
hace 5 años
Mr. Luis.- Do not be discouraged, on the contrary, see how much progress you have made, especially assessing that you do not have an oscilloscope, probes, variable power supplies, multimeters (we have 4), ammeters, esr meter, flyback, capacitometers, technicians or colleagues That they are supporting it, (we are 4 technicians) etc. etc. - the distance that separates us and only, is to recognize what has been achieved, we still have options, in addition not all the procedure is mine, there are the partners, technicians contributing their ideas. ......
2.308
hace 5 años
.... the 100w focus will connect it to the vca input even if it has another focus it can be placed in parallel with the 100w one.- we will remove the flylbck and the hot one and check if it has b +, if we still don't have b +, we will remove the chopper and we will apply vcd on pin 17, about 50vcd, this in order to be sure that the "channel" of b + to the flybck pin does not have any short or overconsumption. . If you do not have short we apply vcd to pin 13 and pin 10 of the chopper, this to check the voltje and 12vcd consumption are sufficient.
2.308
hace 5 años
You can connect the "low or high" probe on pin 17 to check if at the moment of power up we have vpp, you have to be very careful because it is usually only a "record" (an instant measurement) .- if we do not have b + voltage with the focus of 60w, we will have to place the resistance of 680 ohms 20w of the b + to ground, this because by placing a resistance we can have the voltmeter in parallel and know if we have any consumption ........
2.308
hace 5 años
Mr. Luis.- I will send you a diagram to analyze. The optocoupler led has to turn on at 125 / 140vcd, then if we remove the optocoupler and the chopper; We apply a voltage that we can increase and take it to a point where the external LED can turn on, we will know how much b + is turning on, if it does, or we reach 123/130 and the LED does not turn on. it is easier for us to check the flyback, with an external source and oscillator and then check the secondary part of the switched source. Regards.
23
hace 5 años
Good morning Felipe A.! Thank you for your comments and contributions, greetings and thanks to the people who work with you there and contribute their ideas to this type of TV failures ... I commented that last night put the dimmer back to 80VAC at the entrance of the TV and perform the tests and everything happened as I wrote, that is, that + B falls to 0v with the focus 100w (then change it to 60w), it had a value of 7.2 Vdc in + Vaudio and -17Vdc in -Vaudio, in pin1 of the opto there were 6.6 vdc and in pin 2 there was 5.63 vdc approx, on the other side in pin 4 of the opto there were 9.56 vdc and in pin 3 ALWAYS BRAND 0v (in plane indicates 5v)
23
hace 5 años
measured with the probe in the mosfet and with the focus placed on the output capacitor, the measured voltage is 30-55 vpp (similar to the previous TEA1506T placed) but with the difference that the frequency increased quite a lot since it can be seen in the circuit with NEON installed in the drain leg, when removing the focus as the output voltages increase (they seem to be floating voltages) but the IC (ASD) tends to be disabled by lowering the frequency almost to zero, what I observe here is that with the Low or high frequency that takes the ASD, the voltage measured in mosfet is almost the same and is low 30-55v
23
hace 5 años
the voltages that supply vcc (ASD) seem to be the same at all times with focus or without focus on + B, that is, in my opinion, the auxiliary winding of the choper (legs 2 and 3) is not generating the voltage that should keep the IC energized. Once it starts working (only the value that feeds it is observed and that comes from the auxiliary source through capacitor 2532 and diode 6512, it is noteworthy that at all times of the measurements I have noticed that in leg 3 of the opto I do not measure any voltage and according to the plane because there must be 5 v in normal conditions since that should arrive 1.33vdc
23
hace 5 años
those 1.33vdc should reach the leg 6 of the TEA to maintain an adequate working frequency according to this integrated datasheet and as can be seen in the TV plane, and what seems strange to me is that it does not have voltage on this IC pin or in leg 3 of the opto knowing that there is a 9.5vdc in leg 4 of this same opto 8, the opto was already changed by an 817 that I got and everything remains the same
2.308
hace 5 años
Mr. Luis.-The focus will always be in series with the TV. and the current will depend to a large extent on the consumption of this one.- If another focus is placed, the TV will have more current.- that is why the boards have 3/4 lights to increase the current and thus bring the voltje and the current at normal consumption, without losing protection.- On pin 3 of the optocoupler, there will be no voltage, because the control circuit, transistor 7571 bc 547 which is the one that feels the voltage of b +, does not receive the reference voltje of point F 552.- that comes from the cathode of diode 6551.-
2.308
hace 5 años
He has not told me if he analyzed the diagram I sent him: it is with a clip, as sourcetest2.) .- With this diagram, you can see that by removing the chopper, we can attach a 125 / 130vcd source and apply 12v to the sensing transistor to take it to a point that turns on the external led, because we must remove the optocoupler. I agree with Mr. Jose Antonio, but not having a record in the b +, we must apply a voltage on pin 17 that allows the transistor to operate and we check how much voltage it needs to turn on the external LED.
2.308
hace 5 años
Tomorrow / night I will send the diagram of the source we use, it is from a Sanyo TV and the str is 125 / 130. This source with an insulating transformer. Now we have a switched source that has no opto. Another option and only as a last option would be: remove the optocoupler and connect between the 3/4 pin a 100k ohms control with a 10koms resistor. varying this control we can adjust the voltage of pin 3 to 5v. I have never personally done it, but I know technicians who talk about it. so I will investigate it, we will test it and tell you if the source responds.
23
hace 5 años
Good day sir. Felipe A.! Thanks for the diagram, so far I could analyze it. According to what I appreciate, you must remove both choper and the opto coupler and place an external LED where the opto was (pins 1 and 2), and you must use TWO external sources: a variable on the side that corresponds to + B and a Fixed 12 VDC on the + Vaudio side to power the external LED control stage and observe what voltage of + b the LED should turn on, I think it is all right to perform the test, although I have to get these sources first and let you know of the result .... thanks
23
hace 5 años
What I do not understand from the diagram is that it also has an external 6/9 vdc source drawn on the pin of the base of transistor 7573 and according to what I understand of the diagram, because this leg is receiving a high voltage because it would be enabling and sending disable the opto regulation stage and then turn off the main source, that is, this is the function of the stdby_com pulse (3.3vdc) emitted by pin 15 of the Hercules to send the source to disable when it manages to detect any failure in all tv ... thanks again
23
hace 5 años
Good evening Mr. Felipe A.!, I inform you that I was able to analyze the circuit of the source you sent me and it is quite practical ... thank you ... although I have not yet achieved the fault because I have learned a little more about the operation of this type of regulation stages with energized optocoupler with external sources ... I can tell you that I managed to build a variable source with the dimmer that I already had and using a diode rectifier bridge and a capacitor as well as a focus as load to this circuit to be able to vary the voltage of the same, although it was not 100% stabilized because it was of
23
hace 5 años
It was very useful for the test performed, an additional 12v source was placed at the point that you marked on the diagram sent and the choper and the optocoupler were removed and in this place a normal LED was placed, the results were helpful since We were able to verify the operation of this stage without problems, the VDC voltage was increased in + B until it reached 121 VDC and at this moment the LED began to emit a little light and then the voltage was increased up to 125VDc until the LED it is seen to turn on normally, it was measured on the BASE leg of transistor 7571 and on the
23
hace 5 años
In this transist pin, a value of 6.5 VDC was obtained, very similar to that indicated in the diagram of this TV, all this indicates that this stage is working normally (in my opinion it is like that) and this makes us rule out some fault in these components. From what is observed it seems that the optocoupler diode is not polarizing properly since the voltage of + B never reaches a value of 125 VDC and therefore there is no voltage on leg 3 of this optocoupler that can feed leg 6 (ctrol) of the TEA IC so you can control the pulse rate in the mosfet
2.308
hace 5 años
Mr. Luis. Congratulations!!. It is not easy to do tests like these when you do not have the necessary equipment, when you have to make a source, to go try something without having several multimeters at hand, to check how much we have of vca, how much it measures at the output of vcd, how much is the adjustment voltage, someone who is checking the led and another looking at the ammeter. etc etc. I am sending you the diagram we use as a source, this is from a Sanyo TV. It must be used with a 110 / 110VAC insulating transformer. - It was sent as a sanyo source - ......,.,
2.308
hace 5 años
.... when the sensing part works, I think it would be convenient (except for your best opinion) to check the flyback.- if you already have a variable source isolated from the network, we only need the external horizontal oscillator, this with the probe and you can check the vpp in the hot collector. This is because to a large extent the microphone has to recognize some pulses, both horizontal and vertical. If the source in the secondary part works, we can polarize the collector / emitter part of the optocoupler.- I tell him: talk to one of the technicians and tell me that if they have succeeded, but that .....
2.308
hace 5 años
.... on other occasions the source has swung erratically and so much that they have ended up burning the source.- The critical part of the source is transistor 7514 and on the part of the mosfet, the section of the "S" its resistances, from the Pin 9 of the tea to the source of the mosfet. For another side retaking the optocoupler, you commented that they had already changed it. The chopper can be tested with a fly Orozco Oro flyback meter, using it with a variable source.- The horizontal oscillation is 15750 cycles, and the chopper frequency is 25 / 70k. cycles
23
hace 5 años
good afternoon friend Felipa A.!, the diagram you sent me from the source is not very clear when it is sent to open ... on the other hand I have not yet understood the exact location of this source and what is the purpose of replace with this source the one that is already installed on the tv ... is it for any specific test? ... thanks for attending to my case ... another doubt I have is that if what you tell me with respect to the The source oscillates erratically and can be damaged is when the pulse of the opto coupler is simulated in the ASC pin?
2.308
hace 5 años
Mr. Luis. The Sanyo source diagram is for you to have a source for the tests. is the one we use to test the secondary part of the switched source, (which I already check) and to be used as an external source to check elf lyback.- As I am already learning to delete the photos or diagrams that I send you, I can send you a diagram , confirm it and delete it. I think it would be better because it is easier to look at this and analyze it than to write. (I'm looking for a way to have space like you to write) by the way that last night it was too late but I sent him the .....
2.308
hace 5 años
digrama of how to check the chopper. Today, I will send you the flyback tester diagram we use. They analyze it and tell me. With respect to simulating the optocoupler pulse, they will affirm that they leave it for last resort because the source has oscillated so much that they have not been able to control it. On Saturday I hope to have a TV and be able to do the test. regards
23
hace 5 años
OK thanks
I'm going to find out if I can get components for the choper test oscillator and verify its operation .... Do you have any tips or information on values that tell me during this test if the choper coils may be failing?
2.308
hace 5 años
placing the flyback tester, and as you can see in the diagram I sent you, pin 3 of the chopper goes to ground, and pin 2 we can place a diode and a filter to place the voltmeter and we can check the voltage. of the other windings, we place the probe and we check the vpp of the outputs. I will send you the Ing Orozco flyback tester later. and apart we use a source that of str 30125/30130. I will do this by hand and send it. When I have them, he confirms me and I can delete them so I can send him other tester diagrams, do you think? regards
23
hace 5 años
Good evening, friend Felipe Antonio! I hope you are well! : one to feed the oscillator with 555 (dev. 12vac) and another to feed the primary winding part to oscillate also called + B (in flyback test), although this source without load and rectified mediates me about 40VDC (double dev . 12vac + 12vac) then place it in the choper because it seems to fall to 14 vdc (I doubt it ....
23
hace 5 años
... I think I doubt how much it was that the choper primary was fed ... additionally I noticed that the 12vac winding was actually voting a little more (approx 14vac) and this when rectified it emitted a final value without load of 20.5 vdc and according to the diagram because this was the power supply of 555 which caused me concern since I believe that the supply voltage of 555 is at most 18-20 vdcy I don't know if it works well as an oscillator, however they are I saw that it will overheat itself and with the help of an oscilloscope software on pc this oscillation was measured and it reached ...
23
hace 5 años
.... a maximum frequency of 6 kHz or 6000 hz ,: with this frequency value and the supply value provided by this small source of the ING. Orozco proceeded to measure in the auxiliary winding with tester (after the diode and capacitor) and with oscilloscope probe (pc), the tester could appreciate a value of 35 vdc approx and oscilloscope a rms value of 30 v, the winding of The output (legs 17 and 18 of choper) was measured with an oscilloscope tip and a rms voltage of approx. 192 v was appreciated and the same input frequency of 6 kHz, which causes me doubt is whether the measurement with this type is well done. .
23
hace 5 años
... of low current source made with 12 + 12vac double winding (which uses cto. ing orozco), the frequency generated by 555 is high although a little low with respect to the working frec of both the choper and the TEA1506t ranging from 25-175khz, the exact values of capacitors that are given in the ing circuit were placed. Orozco and I don't know if it is the max output frequency. Although everything caused me doubts about not using an external source and the frequency of 555 because I observed variation in the output of the choper windings indicating that they are working and responding
23
hace 5 años
with this little test of the choper (although with a little doubt) because in my opinion this choper would be working in a normal way .... what could you indicate to me? .... another test with an external source of higher voltage will be necessary ?? ... it seemed strange to me that with 14 vdc (value at which this voltage fell when the horzontal transistor was connected to the primary winding of the choper) it would be giving me an output value in auxiliary winding (legs 2 and 3) a voltage of 35 vdc and the tv plane indicates a value of approximately 16 vdc with a value of 170 vdc that feeds the choper (main capacitor) ... thanks
2.308
hace 5 años
Mr. Luis.- All measurements are correct and I agree with you in everything.- If the multimeter indicated 40vcd; it is because 40 between 1.41 are 28vca, that means that from the central tap to the ends they are 14vca.- The 555 needs 12vcd, so you can place a 7812 regulator to set the voltje at 12vcd.- It was important to induce a volltje in the primary, and know if pin 2 could supply voltage to pin 2 of tea 1506, (15.5vcd); This result has been fully achieved.- Now in the flyback it is sought that it does not have short, that it oscillates and we have high tension in the connector ......
2.308
hace 5 años
.... the chopper is "similar", only that for operation it depends not only on the applied voltage but also on the frequency.- This is because the shape of its windings, wire gauge and turns are special .-- Now it is necessary to arm an oscillator of 15700 cycles, (as the diagram of the teacher Luis B; is in the section of contributions and manuals) or look for an oscillating coil of a TV b / w and arm the circuit) .- With the source of 40vcd and an oscillator of 15700 cycles, you can make another measurement and compare the parameters obtained. .....
2.308
hace 5 años
.... it is better to measure with the probe and later with the oscilloscope.- I send you a diagram of the optocoupler resistance placement.- you can use the 40vcd source and do a momentary test.- if you already check the resistors and the filters, you will have to check the diodes, both the normal ones and the zeners.- well, if you already check, the sensing part of the source, and the chopper is working, we only have to check the components of the primary part, and check the flaybck and its secondary voltages. ......
2.308
hace 5 años
I am going to send you some diagrams tomorrow / night, I hope I apologize, because I will do it with "hand and rustic" - we have a wizard but I don't have so much practice - greetings.
23
hace 5 años
Good day! thanks for reading my mzjes !, a question ... the cto with the triac that you sent is to get a dimer of variation of vac at the entrance as we did before ?? .... as for the cto of the oscillator of the master LUIS B. a regulator power point (7808) is observed, this value must be supplied by an external source?, The other tip goes to the TSH collector and flyback, should the flyback ground be placed? (I don't see it indicated in the circuit); on the other hand I ask: all this test should be done with flyback outside the tv?
2.308
hace 5 años
Mr. Luis.- You don't have to say thank you.- I've always thought that these Forums have "something" of military, because of: (not abandoning anyone), I think that's why I'm still here, I like electronics and I remember my Million days.- --- 1- The dimer is the one we use, I send you a diagram, so you can compare it with the one you have and choose the most convenient one.- 2.- I send you a tester diagram that we use to test zeners diodes , diac, varistors, and darlington transistors of power.- 3.- The oscillator of Master Luis B.- uses a 7808 so he can use the source that has 14v ..........
2.308
hace 5 años
.... and place it at the entrance of the 7808, by the way you will have to look for the datasheet, because it seems to me that the input is not as it is in the diagram. Personally I have not checked, because I have the coil for years. We test the flyback in the circuit: 1.- the b + of the flybck power pin is disconnected.- 2.- the external source is connected to the flybck power pin, you have 40vcd to start. we need 60 / 80vcd and 90maxima.- 3.- we will remove the horizontal output transistor (hot) and at the point of the hot collector, there we will place the collector of .......
2.308
hace 5 años
Transistor of the tester of Master Luis.- the probe will connect it to the hot collector.- we will connect everything and check how much it has of vpp. .- According to the diagram the b + is 140vcd.- the constant of vpp is 1000, and the voltage of its source is 40vcd.- the rule of three.- 40 per thousand, between 140, result 285vpp.- all this with the flyback in the circuit, and the connected yoke. It means that at 90vcd we will have a vpp in the 642vpp collector. I will send you a diagram about these connections, so you can analyze it.- greetings
23
hace 5 años
... but it could also be caused by the malfunction of the oscillation of the main source. I summarize a little what happened so far, since my focus has been on this source and for this I totally isolate myself from the flyback and others and attending to all the comments seen in the other forums because I put focus as a + B load but also I have seen that this source should be with stable voltage at its output even without load placed and taking all these contributions since the super-commented tests have been carried out in this forum (I believe that even an article of this fault can be written)
2.308
hace 5 años
hace 5 años
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[img] https://cdn2.yoreparo.com/uploads/imagen_post/0003/65/358ffa9a1b95b99d40700/99b3d4d4b4b3d3d00b3b3d3d00b6
[img] https://cdn2.yoreparo.com/uploads/imagen_post/0003/65/358ffa9a1b95b99d40700/99b3d4d4b4b3d3d00b3b3d3d00b6
23
hace 5 años
Good afternoon friend Felipe Antonio, thank you for reading my question and giving your suggestions in the case .... well, I think your suggestions are very good although I think that removing the flyback in this case does not seem to me, since, as I indicated from The principle is that the main source is completely isolated from the rest of the circuit when coil 5552 is disconnected, so that the voltage of + B is not present in any other part of the electronic circuit ..... I have checked the filters by removing them from the circuit and they seem to be fine since they are loaded and unloaded when tested directly
23
hace 5 años
I do not have a frequency meter or oscilloscope but I am thinking that the IC TEA1506T is not working properly, according to contributions from other forum technicians I have seen that they send the mosfet together with this integrated and sometimes even the opto-coupler although the latter checks outside and it's ok .... excuse me which part of the circuit calls them "hot"
23
hace 5 años
Sorry for my delay in responding but I am in Venezuela and here there are a thousand failures of the electric current supplied by the government company and also the Internet is not very good to say ... I really need to locate the fault of this TV already I have had it for more than two weeks and I still do not give the true cause of this TV failure .... PDTA: the pulse of 3.3 volt that the Hercules should emit to disable this source is still missing ... Someone me I could say what are the sources that should be present in the Hercules under the conditions described
2.308
hace 5 años
Mr. Luis.- The hot, is (horizontal output transistor) .- Download the diagram.- Options.- 1.- arm a dimer and place a 100w light bulb, adjust the dimer to 50VAC, in parallel with the focus connect the plug, so you can take the voltage drops without exposing the components. Option 2.- Place the plug in the secondary of a transformer that has an output of at least 30VAC. So you can also take the voltages. Option 3.- I send you a diagram of the probe that we use to check the pulse in the drain of the mosfet of the primary source (calling side ") .- greetings.
2.308
hace 5 años
I send you a diagram of the probe that we use, this can be placed on pin number 5 of the chopper. probe to see that we stay rustic, but it works. in electronic community is the original probe. We have only varied the value of the components, because it is what we have at hand. (here we also have lacks). Regards.
23
hace 5 años
Thanks Felipe Antonio for the probe diagram, I will try to locate components and assemble the circuit .... a question ... the positive and negative output of this diagram goes directly to the multimeter voltage meter ?? ... What voltage should it measure to verify that it is in the correct oscillation values? ... as I had already said at the beginning because the TSH (horizontal output) was achieved shortly .... I already have a new one but the Measurements have been made without this TSH being present in the circuit and additional measurements have been made with a 6-watt spot load at + B
23
hace 5 años
"" Options.- 1.- arm a dimer and place a 100w bulb, adjust the dimer to 50VAC, in parallel with the bulb connect the plug, so you can take the voltage drops without exposing the components. Option 2.- Place the plug in the secondary of a transformer that has an output of at least 30VAC. so you can also take the voltages "" ... excuse me! I did not understand the location of this dimer in the circuit .... is it at the AC power input? and what function does this pin perform there, does it perform the same measurement probe job?
2.308
hace 5 años
Mr. Luis.- You can check the oscillation in the collector of the Driver, Base of the horizontal output transistor, without having the flybck or the horizontal output transistor connected. For this we have another probe, same that I send diagram), as you can see only the capacity of the diodes and capacitors change. We use 1n4007 diodes because the maximum volume we use to test the flyback is 50vcd.- I sent the first one because for now we are only working with the primary source (the input one) and you need to know if it oscillates. Regards.
2.308
hace 5 años
The diagram shows the positive and negative where they are connected and the multimeter is placed in the vcd position.- Two ways to test the probe.- 1.- measure the vca, multiply it by 1.41 and the result by 2, This last result will be what you have to measure your multimeter.- Second way.- Look for a TV that has an oscilloscope of the driver's collector, and check the vpp of the TV, connect your probe and measure the vpp of your probe. there may be a difference, (for more / less components) but with a rule of three you can get the percentage. Regards.
2.308
hace 5 años
From the First Option, .- When assembling a dimer you have control over the voltage, and the focus responds to the changes. -the voltage changes between the ends of the bulb. This is what is used, because if the focus is set to 50v, and in parallel connect the plug of your TV, you can take its voltage by increasing or decreasing the input voltage. this allows to know how the voltage drops of the resistance of the circuit pins behave based on the changes of vca.
2.308
hace 5 años
Of the Second Option.- If you have a transformer like those of the modular ones) some have an output of 30 / 40VAC in the secondary. The secondary of this is that it connects the plug.The probe connects it to the drain and is the reference that you will have to know if the circuit oscillates.- There is even a post, where removing the optocoupler and connecting a 100k control with a resistor of 10k ohms, at one end, moving the control, the primary (hot) source has to oscillate, therefore there has to be a "record" of secondary voltage. Regards.
23
hace 5 años
Good morning friend Felipe Antonio ... "The diagram is marked positive and negative where they are connected and the multimeter is placed in the vcd position.- Two ways to test the probe.- 1.- measure the vca, what multiply by 1.41 and the result by 2, this last result will be what you have to measure your multimeter. It is not very clear where I should measure with this probe ... is it at the AC voltage input of the line ?? .. here in my AC network we have 115 VAC and when measuring in the input condenser 2507 because I have 170 VDC that are the same that reach the leg of the drainer of the mosfet through choper
2.308
hace 5 años
Mr. Luis. If you have 170vcd in the drain and this voltage divides it between 1.41, it is 120VAC. (115VAC for tolerance) .- But this measurement does not indicate if the source is oscillating. - The focus when connected to the b + causes a load to The source, but when placed at the entrance of the line, acts as a fuse, which protects the 120VAC line and tells us if there is any short, but we have no way to decrease or increase the input voltage (voltage) alternate) .- The latter is what we are looking for so that you can analyze how the source behaves to variations in vca.
2.308
hace 5 años
When you assemble the probe (that of 2kv capacitors) .- To test the probe do the following: .- 115vca by 1.41 are 162v by 2 are 324vpp.- this is what your probe should measure, it does not measure it as is because The diodes cause a voltage drop. The probe places it in the drain of the mosfet and in switched source of the screens the voltage that is handled is 400vpp.- greetings.
2.308
hace 5 años
I comment: for now we are with the source. But we can test the flyback with the probe, simply by decreasing the vcd of the flyback b + pin. I will send you the photo of the probe and photo of the measurement. Regards.
23
hace 5 años
excuse! please, if you have a bigger and clearer picture of the source, you can send it to me and the procedure of connecting it to the electronic circuit
23
hace 5 años
Good day ! thanks for the connection photos of the probe ... although I was referring to how to connect the circuit that you sent me from the oscillator to test the flyback and the external power supply of + b ..... I wanted to see a diagram of this oscillator but a little bigger and clearer ... thanks again ..... I am in search of the high voltage diodes and 2 kv capacitors for the probe since the one I made is "low" capacity
2.308
hace 5 años
I am going to send you a photo of the oscillator that we use, to test the flyback and not depend on the oscillation of the jungle. It was taken from a bn tv. I don't have the original diagrma anymore. As you can see it is already old, so I sent a more modern oscillator, since in mine, there are no more oscillating coils. In question of the source we have a source of a printer or a transfuser that provides 40VAC this gives us 56VCD. which is enough. When we need more voltage I have a source with a 30125 str from a Sanyo TV. Regards.
23
hace 5 años
Good afternoon friend Felipe! one question .... the diodes of the high probe are 10 nf (0.01) and those of the low probe are 100 nf ??
2.308
hace 5 años
Mr. Luis. to the capacitors question.- Yes! .- This because 0.01 are more selective than those of 0.1uf.- We had a better record with those of 0.01uf.- when we tested the probe at 50v.- I will send you the oscillator diagram that we use, if you get an oscillating coil of a tv bn would be useful to you.- this diagram I send you has at least 15 years with us Regards.
23
hace 5 años
Good day, Felipe Antonio forum mate ... in advance I thank you for all your contributions to our questions, I hope you are having a happy Easter with your family ... on the other hand I leave this concern for when you can review This mzje became that this week many are resting .... in my case then more or less the same but also looking for components for the test circuit .... I tell you that I managed to build a dimmer with focus of 100w / 115VAC to to be able to take low values at the AC input and test the measurement probe, the results I write here.1._ I measured with
23
hace 5 años
1._ measured with tester in the electrical outlet as well as in the terminals of the 100w focus that the dimmer has, it is possible to say that the values are quite approximate since the dimmer built it as simple (some people place it a strober circuit with resistance in series with capacitor and these in parallel to the load ,,, but in my case I do not place them and I do not know if necessary) and the voltage adjustment stability in these terminals tended to vary every time and I don't know if this was due to the dimmer circuit or that something was missing from it ...
23
hace 5 años
... what if you notice from last night and today that culminates measurements that our electrical network presents instability in the values of AC voltage that they deliver to us, since, when it mediates in an instant 115 VAC then at another time it measured again and the value it varied at 120 VAC, 124 VAC or 113 VAC and this brought me inconvenience in measuring when I adjusted to dimmer to 50 VAC or 80 VAC, since at the moment I only have a multimeter to measure and it was my turn to change from one place to another to verify values: That being said, I proceeded to take values in the circuit in this way: directly to the network the tester
23
hace 5 años
Directly to the mains, the tester gave me a value of 118.3 VAC (this is equivalent to a VPP = 333.6 VPP) and with the probe it gave me a value of 228 VDC, which is equivalent to a percentage of probe pressure of 68.34 Approx.%, then place the dimmer to the power outlet and set to 78.6 VAC (approx for variation), this is equivalent to VPP = 221.65 VPP .... the tester measured a value of 220 VAC, which is equivalent at 99.25% accuracy; then dimmer was adjusted to 49.3 VAC in focus (VPP = 139.03 VPP) and tester with probe at 217 VDC, equivalent to 156% (it creates me for the measured values higher than expected)
23
hace 5 años
Well, taking these values into account, the only thing I could see is that the probe is more accurate with the measurement values at 78.6 VAC (in focus terminals), I don't know if this is enough to test this probe. What can you tell me about the missing values? I have to continue with the measurements directly to the TV like this, you have to make the same measurements in a TV source by placing these dimmer values at 50 and 80 VAC ... if so, the question is that if to do the other measurements under those conditions I must have the + B and other isolated sources so far and measure with that voltage in
23
hace 5 años
the same measurements must be made with the input voltage placed at 50 VAC and also at 80 VAC ?, even when we can observe more pressure on the probe with 80 VAC. It is safe to measure in mosfet with these values without it being burned to be working as forced in the circuit under these conditions .... excuse so many questions, I want to learn about the subject and I know that you like many colleagues The forum has great knowledge on this subject, since they are concerned with their enormous accumulated experience and have been of great help to other people ... thanks
2.308
hace 5 años
Mr. Luis.- I thank you for your words, but I only participate. I could name him a dozen names of Masters and still lack space and in the end I would have to apologize for the unnamed.- Now the way to take the vca, the vpp and the percentage of each measure, everything is correct. It is to recognize the taste he has for electronics, knowing the hours to spend with a pencil and notebook, in addition to having the inconvenience of having only a multimeter, we have 4, and yet we battle him. ....
2.308
hace 5 años
.... I comment as we check the source: we remove the flybck and the hot, we put a resistance of 680 ohms 20 of the b + to ground. We use the resistance because at 140vcd, and a resistance of 680 ohms the current is 205ma.- At a voltage of 80 / 120vcd the current would be 117/176 ma.- we will connect the multimeter in the b + and check how much voltje we have, we will know if the current consumption is consistent with the resistance we have as a load.- If the current is acceptable we have to check the flyback. We will need a source no larger than 90, isolated from the network.
2.308
hace 5 años
an external horizontal oscillator, so as not to depend on the original feeding, nor on the oscillation of the jungle. we can apply a voltage of 30/60 / 90vcd to the flybck and take note of the vpp of the collector, the measurement and behavior is linear. You are right, commenting that the source even when it is unstable, but the primary part oscillates, and in the secondary part we have the regulation circuit and the one with the highest consumption, the flyback, then the option (except for your best opinion is to test the flayback) .- thanks. best regards.
23
hace 5 años
good afternoon felipa antonio !, thanks for attending my query .... I remind you that I am still with the main source and the + B isolated from the rest of the circuit as well as the + vaudio and the -vaudio in order to find the oscillation and the instability of this source .... I already performed the probe tests and the results were the ones written above and I think the idea of the probe was to see how much VPP was in the mosfet drain to see if the TEA1506T oscillation was good (I suspect he is working badly), I also remind him that he had already made a circuit with cndesador and NEON
23
hace 5 años
with the neon cisrito the pulse count was made and it was 120 pulses in one minute, which indicates that its frequency is very low but it does not tell me if the TEA1506T is damaged or not .... I just performed the measurements with the probe high in the mosfet using a dimmer in the VAC input and placing in it a value of 52.5 VAC and 80.6 VAC approx ... the results were almost similar in the measurement pins, with 80.6 VAC in input I measured 160 VDC (direct with tester) in main capacitor (2505), 116 VDC in + B, 12.5 VDC in + Vaudio and -16 VDC in -vaudio, with the probe could be measured
23
hace 5 años
with the probe measured the mosfet drain with a value between 34-55 vpp in drain and in gate obtube 2.2 vpp approx, then place a value of 52.5 VAC on the VAC input with the dimmer and measured the same points and these were almost similar to the previous ones: 116 VDC in + B, 12.5 VDc in + Vaudio, -18 VDC in -vaudio, 163 VDC in main capacitor, 11 to 9.3 vdc in vcc of the IC and in the same way with the probe get a pulasante value in drain between 34-60 vpp and in gate 2.3 pulsating vpp .... in summary they are almost equal and the frequency is the same and low as I appreciate
2.308
hace 5 años
Mr. Luis.- the probe and the oscilloscope cannot be placed in the "G" of the mosfet. Only in the drain. -If placing the probe in the "D" the voltage is 34 / 45vpp is too low. observing the diagram should have 295vpp mosfet 7512.- If possible, it will put the load resistance 680 ohms 20w, but place the focus and we will check only the b + and the vpp of the drain. , because the voltage of 163 is normal. (163 between 1.41 are 115VAC). Then we only have to place the load and check the regulator circuit. transistor 7512 bc547.
23
hace 5 años
Well, thank you for warning me of not doing gate measurements ... although I already made them with those measurements ... I hope I have not damaged anything ... What is the danger of measuring at that point? What can be damaged? .Well since I have no resistance with that power then place a spot there ... 60w or 100w does it work? ... Well, I tell you to remove the TEA1506T and I am waiting for a partner to bring me a new one that It has to place and measure to see (although I suspect this integrated because I am not 100% convinced.) ...
23
hace 5 años
When measuring with that resistance or focus in secondary with + B isolated, what result is sought there? What values would indicate to me that something of the regulation circuit is failing? ... I understand that this circuit is fed back to the optocoupler and resistors that take the + Vaudio sample (+ 16VDc according to plan), what I observe is that this source is also down at all times and the optocoupler achieves in its legs1 and 2 a value of 8.7 to 9 VDC and 8.1 VDC in leg 2, which m indicates a value a little low according to plane but higher than 6 vdc of stambay
2.308
hace 5 años
Placing the probe or oscilloscope in the G of the mosfet causes it to stop oscillating.- from the chopper 5531 check on pin 8 after the diode 6536 the filters 2535 2536, these are 1 / 2.2 uf at 10v. This puts them in a critical place because if they are altered they may not filter and consequently cause a low voltage.
2.308
hace 5 años
place the resistance or focus, it is because generally switched sources need a load. and based on this we can measure how much voltage it supplies and how much current we have.- it is required an esr meter to be able to measure all the filters and have a broad picture of how the filters are, especially those that are subjected to a continuous voltage but having low vcd values.
23
hace 5 años
the diode that you mention to me 6536 together with the 2.2 mf / 10 v capacitor belong to the output stage of the stambay source, that is, the 6 v are generated and the other winding of that same choper leaves the 3 v of satmbay .. ... as I told you at the beginning because the Stambay source is working very well ... I was referring to the last paragraph that I wrote you about the stage of regulation of the main source next to the opto coupler, this feeds initially from the 6v of satmbay and later it feeds on + Vaudio (+ 16VDC), the latter is the one that only has 12.5 VDC sometimes
23
hace 5 años
good afternoon friend Felipe A.! I hope you are well, I wanted to ask if for the oscillator circuit that you sent me from ing. Orozco you need the horizontal transistor with damper diode included or if you can use the 2sc1172b that comes without damper included ..... for that same circuit you can use a mosfet
23
hace 5 años
I wanted to comment that I managed to find a circuit with 555 and a stage that oscillates or resonates the choper bobbins to individually test them at this address: http://valetron.eresmas.net/TestChopper.pdf, but I still don't know if these coils are perfect .... a companion brought his laptop with an oscilloscope software installed and he managed to see the oscillations of each coil separately at a frequency close to approx. 130-160 khz, although I saw different waveforms and peak values for each winding because it still creates the question of whether they are totally fine,
2.308
hace 5 años
Mr. Luis.- You can use transistors with damper or without the damper.- Any horizontal output transistor you have on hand will help. In the question of putting a mosfet, I have seen some diagrams, but this has given us good results. If you had a mosfet and placed it, then comment on how the circuit behaves. Tomorrow Saturday / night, I will let you know if I could take the switched source to an operation by removing the optocoupler. regards
23
hace 5 años
ok thanks for answering .... I will be watching the weekend waiting for the results you achieved with the optocoupler .... I will try to test with the circuit as it was sent and then try to locate a mosfet let's see how he behaves himself
2.308
hace 5 años
He was one of the first testers we did, even the author released a new version, later we put together the Bob Parker. - The latter gave us better results, because he has "doubt, regular and good" .- they are all good, only that You need continuous practice to rate each chopper. The Orozco ing tester is the oldest and is still useful. for the b + of the chopper, I think that a voltage no greater than 50vcd would be useful. Regards.
2.308
hace 5 años
I comment that this same circuit is used to test the lcd lamps. - We get a flyback b / w of 12 inches, and we assemble a source with a lm 317 the output voltage of this should not be greater than 15vcd. - and gives us To test the lamps perfectly. We get it from a video on the network.- (I think) it is titled: how to test lcd lamps with flybck tester.- I will send you the diagram later.- However, I believe that with the knowledge you have, the concept is enough for carry it out.- greetings.
2.308
hace 5 años
Mr. Luis.- I send you the photo of the transformer that we use for the tests.- This one has several VAC outputs and we use the one of 40VAC.- The transformer is of a modular house.- Summary: The primary of the transformer is connected to a 100w focus.- the two points that supply the 40 VAC are connected to the TV plug.- when we turn it on, the source throws 125vcd in the b + .- (in the b + do not place any load) .- second step: Remove the optocoupler and place a 50k ohm potentiometer. - This is measured so that the measurement is as close to half (25k ohms) ......
2.308
hace 5 años
the 25vcd frame voltmeter in the b + .- Note.- you have to move the control very carefully, because when rotating it marks 90vcd for one side and 20vcd for the other side.- then: reducing the vca input and placing it in place of the control a resistance of 50 k ohms, between the ends of the optocoupler it is possible to take it to a point of oscillation. preferably use only fixed resistors in order of (50k / 33k) and (50k 68k) .- It should be noted that if we use the 120VAC input, the b + at the output would be more than normal. .....
2.308
hace 5 años
..... this is the reason why the technical partners leave it as the last test. Note: If the plug is connected to the normal 120VAC socket, and the potentiometer moves abruptly, it is the reason why the source oscillates "is packed or runaway" more than what is marked on the b + as normal or acceptable.- It is necessary that the input VCA does not exceed 40 / 60VAC.- I wish I could find a TV oscillating coil b / w to make the horizontal oscillator. or to make the oscillator of the teacher Luis B. both would be of great help for his measurements. Regards.
23
hace 5 años
Good morning Felipe A.! Thanks again for the contribution of the test you did, what I did not understand very well is that you said that with 40VAC at the input you obtained 125 VDC at + B and later after removing the optocoupler you told me that you measured at + B and had a value 25 VDC ... What I understood from using fixed resistors is to place them instead of the 50k potentiometer? To make the test safer ?? ... is that so?, this test is with everything on tv connected (choper and others)?
23
hace 5 años
please if you have a diagram or diagram of connections that you made of the tests performed, you can send it to me .... thanks
23
hace 5 años
good morning Felipa A.!, interesting the diagrams that you sent, I did not see was the diagram of the dimer with triac that you are going to send me .... no I did not understand it was the zener tester circuit, varistors, since it seems that it was a circuit voltage doubler or triplicator although the location of the second diode seems strange to me (one question: are all the diodes here 1N4007?), I imagine that the probes are the outputs after the 1 mg ohm resistors
23
hace 5 años
on the other hand because I know that it is important to know if the flyback is working perfect and you really appreciate those oscillating diagrams to prove it: You have great experience in repairing TVs and I have noticed that you have insisted on testing the flyback, but my doubt is that initially we are focused on the main source to see that it works normally and it was what I got initially damaged along with the TSH in short and the leaking mosfet according to my assessment with tester test, it is logical to think that the TSH was damaged by some fly problem but also .....
23
hace 5 años
... but it could also be caused by the malfunction of the oscillation of the main source. I summarize a little what happened so far, since my focus has been on this source and for this I totally isolate myself from the flyback and others and attending to all the comments seen in the other forums because I put focus as a + B load but also I have seen that this source should be with stable voltage at its output even without load placed and taking all these contributions since the super-commented tests have been carried out in this forum (I believe that even an article of this fault can be written)
23
hace 5 años
Taking the above and going to his high experience in TVs then I ask: the tests carried out so far can be performed without load in + B?, when a focus was used on it should have used some special features? or was it not advisable to have exposed this source to be without load in + B or the focus load is too much ?? (My little knowledge in switched sources tells me that this source should work without load but not everything that one knows is true many times. I say all this, since I have performed the different tests and I still have not been able to solve
23
hace 5 años
... I have not been able to solve and I have tried the feedback stage with the OPTO and others and nothing ... it occurred to me to measure again all the resistances and especially those of low value and capacitors but everything seems to be normal. NOW then take the mosfet (new) out of the circuit again and test with testar and with a test circuit that hise with a led diode and series resistance and bringing the door (G) to a voltage that feeds the entire 7 VDC circuit approx and the mosfet seems to have LEAKS IN ITS FUNCINATION AGAIN, and that put me on the edge, since it seems that you can perform at ...
23
hace 5 años
It seems that the tests carried out on the TV have caused damage to this mosfet again, the previous mosfet was tested with this circuit and it also seems to leak when it is triggered by G and does not keep LED on, an IFR mosfet was placed in this test code and when firing G because the led stays energized, I don't know if this is the best way to test these power mosfet, but they seem to be failing. It is possible to say that initially this mosfet was detected with leaks and TSH in short and for that reason it was changed but the TEA came to change it was after several tests and although its operation seems to be ..
2.308
hace 5 años
Mr. Luis.- 1.- of the zeners tester, if it is a voltage doubler, the second diode "flattens" the form that comes out of the first diode, so we find it and so we arm it (it is still in the network) the diodes all They are 1n4007 and the output is correct, they are the 1mg resistors. 2.- the source has to have a load, we use a resistance of 680 ohms 20w, because the b + of your tv are 140vcd at that voltje the current in the resistance is 205 ma.- 3.- if you use a light bulb 60 / 75w is fine, the current at 140vcd and 75w would be 500ma. .......
2.308
hace 5 años
.... I tell you.- we for a quick or momentary test do not put the load, but if we lower the voltage or input voltage to about
60 / 80VAC and we are located with the "high" probe in the drain, this to have a "reflection" (instantaneous voltage) on whether it is oscillating. 4.- Before I forget, the 7808 oscillator of the teacher Luis B, we will have to correct the connection, not bad, I guess it was for aesthetics of the diagram, but for electronic purposes remember that the connections are reversed. comment that mosfet has his tv, well the stp 10nk80, .........
2.308
hace 5 años
stp10nk80, zfp termination, is 160 w, z termination, is only 40w.- I comment: the problem of testing the mosfet is that the test is usually at low voltage.- we needed to turn on 40 LED bulbs, so we looked for a source pwm and then we found the driver (I send diagram) .- One of the technicians, I noticed that we could test the mosfet, just by varying the source of the drain. When we test LEDs, in the blue dots there they connect and we only apply the voltage that we require, when we test mosfet, we have two options .........
2.308
hace 5 años
.... an option is: to place LED strips.- second option: to place diodes 1n4007 and intermediate of these a focus of 60w. so you can check the voltage and current consumption in the S of the mosfet.- the advantage of this circuit is that few meters can test at 10 percent of the operating voltage. Now we have a switched source.- There are technical colleagues who live 3 hours from the town, and because they don't have equipment they prefer to bring the TV.- You have achieved an excellent job, with little equipment, several nights, many sheets and some pencils. .....
2.308
hace 5 años
.... We recognize the effort and dedication.- There is no doubt that constancy is a virtue and you have it. Regards.
23
hace 5 años
Good afternoon companion Felipe !, Well, if I have tried to put all my effort into being able to repair this TV source and in fact I never like "Throw the Towel before the end of the fight", but so far I have not been able to find the right strategy in tv repair. thanks for your support ... as for my mosfet as the original one was STP10NK80Z (160 W of consumption according to datasheet) and the one that brought me was the STP10NK80ZFP (40 w of consumption), although the currents and voltage they support are the same , the only thing that seems like the new mosfet finished in ZFP should heat less, I think
23
hace 5 años
a question mr felipe a., with respect to the way to test the flyback, in the part that you tell me that you should use the variable source with a maximum value of 90vdc, because my question is the following: how do you get the relationship that 140vdc that must be in + B according to plan because the relation constant of the other voltages must be 1000 ... thanks
2.308
hace 5 años
Mr. Luis- 1.- the comrades comment. that if it has 16v negatives, the source is oscillating. (erratic) but it oscillates.- instead the 16 positives, it only has 7.2vcd.- they comment that you can check that "line" of 16 positives and negatives, (I send a diagram) by placing a source and the ammeter.- 2. - Regarding the flyback test, there are three values that we should know. the voltage of the original source 140vcd (is in the diagram) pin 17 of the chopper, diode 6551, the constant that is thousand; and the voltage of the auxiliary source, (in his case the one of 40vcd that already has) .- ....
2.308
hace 5 años
.... at 40vcd the vpp in the hot collector is 285v. at 90vcd the vpp in the collector is 642v. They will bring a 27-inch TV, and we can do tests with it. both with the discharge probe and with the oscilloscope. So on Saturday night I inform you of the results. please check the diagrams sent, to delete the ones you have and to place others.- greetings-.
23
hace 5 años
good morning brother Felipe A.!, well I respect the ideas provided by the colleagues who are with you there collaborating with contributions to the resolution of this fault, but I do not share them in total, I apologize if I am wrong since you are the ones who They have the experience. The measurements with external source and ammeter in sources + Vaudio and -Vaudio, and although I have not measured them with ammeter, then if I measure it with voltmeter before isolating them completely from the circuit as well as + B and at the time it was not achieved biggest drop in those branches ...
23
hace 5 años
these ammeter tests are a good contribution and serve to rule out failures in the following stages, but as I already mentioned, I had already measured these stages with voltmeter and there was no source load or short symptoms in these branches; I understand what they tell me with respect to the source is oscillating and erratically, that was the initial conclusion that I put in my first paragraphs of this post, the question is why or what is the cause of this erratic way of oscillating . As for the voltage in -Vaudio close to - 16vdc that says the plane, they are not accurate in each med
23
hace 5 años
... these measures are not always the same, sometimes it gives a value of -17.5vdc and other times it reaches -12.5 vdc, the source + Vaudio is always more down with respect to -Vaudio and this should be possible, since, as we can see in the plane because in this branch of + Vaudio there is a small load of the feedback circuit with the optocoupler (it should be remembered that these two sources are isolated from the rest of the circuit), so I presume that this is the voltage difference that exist .... According to what I understand of switched sources because there is a small oscillation in the source at the beginning ...
23
hace 5 años
... when there is an initial oscillation because a small electromagnetic field is generated in the coils of the secondary one generating at the same time an alternating voltage in the outputs and this is achieved to accumulate at the ends of the electrolytic capacitor of each present source but when stop oscillating the source in a normal way because this voltage is reflected the secondary as a floating voltage that when placing a load because it tends to fall because there is no good feedback by the OPTO so that the source continues to work and oscillate normally ... Thank you
23
hace 5 años
On the other hand and with respect to the test of the external sources to test the flyback, because I do understand the calculations that you carry out with the value of 140vdc (according to plan) and the vpp that you must give if 40vdc and 90vdc is applied; What I do not understand is where they get that constant value of 1000 to be able to perform these calculations by rule of three, and excuse me here, what happens is that I do not know if it is a predefined value that flyback must have, since I do not have good knowledge in that matter ..... thanks
23
hace 5 años
good afternoon friend Felipe A.! Greetings to you and your co-workers who contributed so much to my TV failure .... I was a bit isolated from the TV and the Internet due to health problems and attending other occupations of work alternate to repair .... Well I wanted to thank you for all the diagrams sent and ideas and contributions to the solution of my fault ... I tell you that taking a little back what happened because I managed to try the new and original mosfet through an oscillator circuit with 555 (flyback tester ) and using a PC oscilloscope software, the waveform was measured ....
23
hace 5 años
It was observed in the oscilloscope that both mosfet work well at 6 kHz (oscillator frequency 555) but with the particularity that the new STP10NK8OZFP mosfet slightly distorts the square wave generated by the cto. with 555 generating some extra strange peaks different from the original STP10NK8OZ mosfet that despite having both a little leak measured with tester because it seems to be working better, then because thanks to the help of another 21 "philips tv (chassis L03) that I I got to try directly the mosfet mounted on TV cto. since its source worked well, achieving ..
23
hace 5 años
managing to observe that the new mosfet does block the source and the original (old) managed to work well and generate in + B the necessary voltage of approximately 120 vdc which is the one indicated for this chassis L03 according to plan, that is, the mosfet due to leaks that began to presentyar because it does not work well mounted in cto. of TV and I imagine that it will be because it does not work stable at a high frequency generated by the TEA1506T. On the other hand I tell you that for these tests, I put the 60w bulb as a + B load and the bulb turned on and off and in the same way the 100w bulb did.
23
hace 5 años
... in VAC input, which seemed to detect a short or high current consumption, after this the bulb was changed in + B for 100w and the 60w was placed in the input and during the measurement made I realized that this bulb was too much charge for the source and then I remembered what you told me about putting a 680 ohm resistor on + B, since the current is small there, so I decided to place a light bulb 25 w at + B which roughly equals the 680 ohm load and surprise the light bulb remained on and showing the voltage values co
23
hace 5 años
In conclusion, because thanks to another TV I managed to rule out this fault at source and managed to know that the load indicated in + B to make measurements is a focus of 25 w and a 100w protection bulb must be placed at the VAC input, since the 60w takes too much current to the TV input and also disables the main source ... I already took the flyback and tried it out of the chassis and it is working correctly, my question is: if I can place a light bulb in series where it is coil 5552 to feed the TSH and flyback to continue testing and avoid any short in later stages
23
hace 5 años
I really thank you for each of the contributions made, since although I have not finished with the TV because I managed to guide a lot in this fault and has given me a hundred knowledge and learning in this type of TV failures .. .. I'm going to keep measuring and I'm informing you .... thanks
2.308
hace 5 años
Mr. Luis. It is a pleasure to greet you, to know that you are well, and in terms of health, then take care of yourself. Regarding the tv. Congratulations !!! .- It is to be praised, how much you have achieved with the little you have at hand. Now with respect to flyback. Although I already tried it outside the circuit, you can check it in two ways: 1 as you suggest placing a focus between the b + and the power pin, only instead of coil 552, I think it would be better in coil 5410, (pin number 3 of the flybck) .- we place a resistance in series with the focus of 4.7 ohms 10 w, this to place ......
2.308
hace 5 años
the voltmeter in parallel with the resistance and to know the consumption current. the second option: is to feed the pin number 3 of the flybck with an external source 50 / 90vcd, and an external oscillator. With this, you can check the vpp in the hot collector at several voltages. taking into account that you already have the vpp probe.- with the latter, you would not use the original source, nor the jungle oscillation. .best regards . Felipe ascencio
23
hace 5 años
Good afternoon, Felipa A! Oscillator of the teacher Luis in the second part that you explain because I notice that this cto. Oscillator already incorporates a horizontal transistor, you must remove the TSH that brings the TV to place this oscillator, which would indicate the VPP values measured with the probe. I only have a source close to 40vdc, that of the dimer is not stable, since without loading the value in the focus ....
23
hace 5 años
without load and with dimer the value in focus is adjustable between 22 vac to 120 vac but when placing the load that would be a rectifier bridge and electrolytic capacitor of sufficient microsphads to filter VDC because the source raises the final voltages too much at the output making them only variable from 115 vdc to approx. 150 vdc (the latter did not measure it completely for fear of damaging the other bulb that had a charge parallel to the output capacitor), which is what is sought with this measurement by varying the + B?, no Should flyback output voltages be better measured?
2.308
hace 5 años
Mr. Luis.- By placing the 4.7 ohms 10w resistor in series with the b + line and the flyback, you can check the flyback consumption.- example: if you turn on the TV, the voltmeter that is in parallel with the resistance will indicate 5vcd , it means that we have 1 amper of consumption, which is too much.- for us the measure must be in 2.5v, which indicates a consumption of 0.5ma. The Luis Luis oscillator, I have not used it, because I have the oscillator with a TV coil b / w. observing the diagram, he uses the lm317 regulator reaches 30v. so it could be feasible to use the oscillator .......
2.308
hace 5 años
.... with its 40vcd source.- With this way to test the vpp in the hot collector, it is sought: to check that the flyback, the yoke, and the tuning capacitors (those that are in the hot collector) function and respond to different voltages in a linear manner. You can check that at 90 vcd you must have an average of 666vpp in the hot collector. Another measurement is to take the vpp of the heater, this is at 18 / 22vpp. If I could get a coil from a bn tv, I would send you the diagram we have. I have confidence, first for the years we have to use the circuit, and also uses transformer .....
2.308
hace 5 años
..... driver transformer, which makes it stable.- basically it can. 1.- place the focus and resistance in series and check the current. 2.- use the oscillator and the source of 40 that you already have. 3 measure the vpp in the heater. It is a pleasure to greet you and I hope it will improve and this better. regards
23
hace 5 años
Of course, but as seen in the diagram of the master Luis, because at the output he uses a transistor with damper diode that would replace the TSH of the TV, that is, that this circuit, apart from generating the frequency of 15 kHz, also uses an output transistor to swing the flyback directly. bone is a direct flyback tester, I say it because of the idea of trying with flyback placed on the chassis is to measure how the entire circuit reacts to the variation of the voltage in + B but when changing the TSH it would be changing the parameters and it would only be observed that the flyback is working ...
23
hace 5 años
I mean that the master Luis's cto is not just an oscillator, it is a circuit that also replaces the TSH, because the oscillator should be connecting is to the base of the TSH of the TV and not directly to the flyback coil according to me. ... on the other hand I wanted to ask if the + B serial bulb should be 100 w?
2.308
hace 5 años
The assessment is correct, and only remains as an option.- if I had a way to get a b / w coil, here there are still those televisions, I could arm the circuit and use the original hot. I think it would be better to use the resistance and check the hearter's vpp. Regards.
2.308
hace 5 años
Basically the circuit of Maestro Luis B, is a fllyback tester.- the other oscillator circuit, if you use the original hot and also the oscillation is more stable in terms of frequency and time. .- with respect to the serious focus of 30/60 W. - connect in series and remembering that the voltage between the ends of the resistance should not be greater than 2.5v.
2.308
hace 5 años
I'm sending you the oscillator circuit that we use, I wish I could get a coil. Regards.
23
hace 5 años
What does "bn" mean when you mean the oscillating coil? ... does it mean it must be good? ... or is it an acronym that uses this coil as a name?
2.308
hace 5 años
Mr. Luis; I hope I apologize, when writing bn ob / n, it means that the coil is a black and white television of those 12 inches, because those of 5 inches, bring an oscillator like that of master luis.- they do not have a driver transformer. Black and white TVs bring oscillating coil and driver transformer. Even here there are places where they sell chassis and any piece that one needs. regards
23
hace 5 años
ahh okk, thanks for the clarification, if it was very far what I thought that meant .... well sometimes it is better to be a bit "asked" and get out of doubt ... thanks again. On the other hand and although not much is the case because I would like to know where I can best get the cto diagram. of the teacher Luis, just to have it in my files, since as you can see it is very blurry and I was drawing it separately and it seems that pin 8 of power was not connected and capacitor 103 that is connected in pin 4 because it should be according to my knowledge on pin 5
2.308
hace 5 años
It is here, in manuals and contributions, as a flyback tester.- the capacitor on pin 4 is only to help in filtering the power supply. As for placing another on pin 5, it usually has a capacitor, as I have not armed it, I don't know how it works or what effect it would have if we put it on. However, Maestro Luis has credibility, so we will assume that he personally oversaw the project. Regards.
23
hace 5 años
Good morning! Well, it is not my intention to damage the credibility of anyone, much less, just because of my knowledge in electronic engineering because I try to analyze every circuit I see or they send me to have a firmer concept of the step I take in the resolution of each failure and not change piece to change because otherwise I would not learn anything and would be asking at all times for a failure similar to each colleague in the group .... I apologize if I did not know to imply regarding the cto. of teacher Luis ... It is possible to say and as a contribution to this forum to colleagues who can read this mzj .......
23
hace 5 años
because when analyzing the cto. I can inform you that according to mathematical calculations the total value of the frequency emitted by this oscillator is 15.08 Khz, since it only depends on the resistance r1 (5k6 // 39k), r2 (10k // 27k) and c (562 or 0.0056 micro farads) located on leg 2 of 555 and determining the on time (ton) and the off time (Toff) of capacitor discharge c, that is, this is an astable circuit with 555 calculated to emit a frequency of 15.08 Khz output and is very important for the flyback test because it is a frequency close to the horizontal of the TV
23
hace 5 años
The calculations of this are the ones used in Datasheet of the IC 555 working in astable mode, thanks for your attention .... I just wanted to contribute something and I do it in a positive way ... I appreciate everything that they have told me and regarding each teacher who has contributed his ideas before ... on the other hand I would like to say that this same circuit should work very well if instead of these transistors a similar high power mosfet is placed or less than the one that uses the switchable source and it is would place directly to pin 3 of 555 through its resistance .... thanks
2.308
hace 5 años
Mr. Luis.- After the analysis that you have done, we recognize and thank you for your contribution.-Definitely many technicians will find it useful, since they may complete it, or take advantage of only the oscillator circuit. Taking into account that, of the old oscillator circuits based on coils and driver, there is no longer.- It is a circuit that we have not armed, but now with what you explained, we will have confidence in sending it to other colleagues. Thank you! .- Best regards. Felipe ascencio
23
hace 5 años
Good afternoon, colleagues in the forum! Taking up my TV, I can tell you that I have made great progress; according to the contribution of Felipe A. I managed to place a 100w focus in series a + b along with a resistance of 4.7 ohm / 10w as they indicated to me to be able to measure the current that passed through the resistance and I got a voltage there between 1.8 vdc and 2.1 vdc, the only thing I saw strange was that the light bulb in series lit too much so I worried a bit, so I set out to measure the flyback outputs: with a high probe I measured a vpp value of 19 vpp and the voltage of - 13vdc ....
23
hace 5 años
... the voltage of - 13 vdc was fine (it was measured with tester here), but when measuring the source of + 200 vdc I noticed that it was dropped to a value fenced to 140 vdc and the TV turned off after approx. He entered Stambay, when he turned on the TV again because he did the same thing again: The series of light bulbs were then bridged at + B but leaving 4.7ohm resistance there, the current flowing through the resistance increased a little and the TV it went off at approx. 25 sec (for these tests a 300w bulb was placed in the vacuum inlet for protection), it should be said that the + b measured in ..
23
hace 5 años
.... measured at c 2552 (choper output) was fine and marked 130 stable vdc at all times, we proceeded to measure at one end of the resistance (pin 3 dev. flyback) with respect to chassis ground and note that the voltage dropped to approximately 93 vdc due to the effects of the resistance (having placed the light bulb in series fell further) and then the TV was turned off again after 25 sec approx. After that I decided to bypass this last resistance so that the voltage of + b reached the winding of the flyback completely and indeed it happened and the TV managed to stay on and the source ...
23
hace 5 años
... and the + 200vdc source kept its value stable in the flyback output as well as other sources, the TV remained on but the 300w focus on Vac input sometimes turned on more than normal and I noticed that when it changes channel and it had too much brightness because the focus was trying to turn on more and lowered its intensity to the rhythm the brightness used by the video of the channel at the time, this does not seem normal and this is when I ask for your guidance to see what it is It is causing high current consumption; It should be noted that when the TV was turned off at 20 and 25 sec
23
hace 5 años
when the TV was turned off at that time because the source went into stambay protection mode indicating pulses or codes of 11.3.2 and 5 flashes. After the TV was turned on and switched it to a channel that had too much brightness as the focus tried to turn on too much and the source was protected again. in short, because the TV remains on but with the focus on the input that increases its light too much when it detects more consumption due to brightness variation or something else .... the TSH and the vertical heat up a little more than normal and the mosfet and the flyback because its temperature is low ... please ...
23
hace 5 años
... Please, if you can guide me here, I would really appreciate it ... it is worth saying that I still have the demanetizer coil disconnected and I have not gotten into the error code menu or the technical parameters programming menu of the tv .. ... I don't know if it was that the eeprom could have been deprogrammed or there is another fault ... I heard another colleague say again about measuring some voltage on a CRT card and lowering the screem to a more normal value but I don't know why where to go ..... thanks
2.308
hace 5 años
Mr. Luis.- 1.- The voltage of 2.1v in the resistance of 4.7 ohms 10w indicates a consumption of 446ma. "Within the normal" .- 2.-subject to what you have to say; we need: an oscillator and external source to be able to check the vpp in the hot collector.- a cd with adjustment patterns, this consists of a grid, dots, vertical colors (3), and a red color for purity adjustment.- This is because to move the focus and the scrreen we must have a grid and points. ...
2.308
hace 5 años
If the resistance of 4.7 ohms is too much, we can use resistance of 2.2 or 3.3 ohms 10w, the case is that we can monitor the flyback consumption. In series with the resistance we can use the 30w bulb that you have - looking for the focus load and the flyback consumption not to be too much load for the source. I am with a computer technician to "see" if we can attach a folder with the adjustment patterns. best regards.
23
hace 5 años
good night !, because with respect to the focus of 30 w because it does not seem to me, since, until now I have noticed that up to 100w is too much load, as it is known because a focus of less power has in its filament a greater resistance to that of a focus of greater power for the same supply voltage ... with respect to the pattern of points because I totally do not know that method ... I will have to explain that part well, what I noticed was that the higher brightness used in the video of a specific channel because the current consumption increases considerably .... with respect to using oscillator and external source.
23
hace 5 años
... well I have not tried despite you have insisted several times, now the problem is the oscillator to use, since I do not have the oscillating coil of tv b / n. On the other hand, what I detect today is that if the flyback does not reach the total voltage of + B, it already begins to have erroneous voltages in its output that are important (source case +200 Vdc); Now despite the fact that the voltage at + B has been stable at all times because I have had the doubt that if it is emitted voltage it is sufficient, since in the plane it says that it should be 140 VDC but in an attached table of this tv it says 130 vdc
2.308
hace 5 años
Mr. Luis.- I tell you the maximum voltage that we have measured on a TV is 135vcd of a Sanyo TV.- So we can get close to that voltage.-A bar generator already has all the functions that are required, but at one time They were expensive, so the CD was used, the color TV adjustment program is lowered, and this has the advantage that having a grid can check the power supply, because if this fails, the grid shows a wave , with the points the focus is adjusted, both come in black and white. so you can see the width, height and graduate it .....
2.308
hace 5 años
With all three colors, they come out vertically, the color and sharpness are adjusted. finally with red, the entire screen of this color comes out, purity is adjusted, this means that you do not have to have any spot of any color. The only thing that remains pending in terms of the flyback is how much has of vpp in the collector at a known voltage ..- It will be possible to check all the filters with a srr meter- if possible and find a place where you can save the data of the memory, this to have them as backup. Espèro de salud be well, greetings.
2.308
hace 5 años
I commented: when the ESR meters were not or were so commercial, I was working in a company and they did the following: -from the secondary output of the driver transformer, from the horizontal oscillator, they took out two cables, one black that is the earth and one yellow, the yellow cable is connected to one end of the filter to be tested, the other end of the filter goes to a vca ammeter and the other end goes to ground. everything is connected and it is checked how much current "goes through" the filter. With this you can measure the filters in the circuit. regards
23
hace 5 años
Good afternoon friend Felipe A.! Greetings to you and to the coworkers who are with you ..... as for the TV I tell you that although I have not managed to make the CD of patterns of setting up TV because I continued testing it with a 300w light bulb as protection in the entrance and in principle the TV lasted a few seconds, the light bulb increased its intensity and the TV went off, so it was being protected by an increase in the consumption current, and this happened in channels where its video brightness was high, I managed to place it on a channel whose video was quite dark and the TV was still on ...
23
hace 5 años
... I was able to enter its hidden menu through the code 062596+ OSD (menu), and managed to erase errors in the buffer, in the same way I could see that the vertical video image was too stretched up and down, for what deduced some error as to some value of the parameters of vertical deflection, observing the image because the parameter called VAM could be moved to a lower value and with this as the image is able to see more adjusted to the screen. in the same way observe the parameters of the USER menu that is present directly from the managed MENU button .....
23
hace 5 años
... managed by the client to adjust the values to his view and his environment where he places his TV and notice that the CONTRAST and BRIGHTNESS values were too high, of course this is an indication of too much wear of the TRC tube I think or because people also sometimes they like to play with the control and they get into as soon as they watch TV menu .... of course when lowering these levels to a value of 40 approx because the TV despite looking a little dark because it manages to keep energized and not It turns off so it changes for any channel with greater brightness, what I have observed is a little magnetized ....
23
hace 5 años
---- the screen, since initially I forgot to connect the demagnetizing coil .... what I see a little strange is that the TV to be turned off by main button (swith) and turn it on again (in stambay ) because the intensity of the bulb rises a little at the beginning and then normalizes. Likewise, by turning it on by the power button of the control, because the bulb increases its intensity enormously and is due to the consumption of the demagnetizing coil and subsequently returns to a minimum level of filament ignition .... I don't know if this be so normal or there is still too much ..
23
hace 5 años
... or there is too much consumption yet, at the beginning ... I don't know if it is better to calibrate with the bar patterns and so on ..... what can you tell me about it ?? ..... The TV has been on almost all day but with the protection bulb connected .... I have only seen the intensity of it rise for the ignition moments as I explained before ... what other stage should still be measured ?? .... thanks for your attention .... Ing. Luis Carreño
2.308
hace 5 años
Mr. Luis.- You have checked the primary oscillation stage, sensing stage, horizontal, vertical stage, parameter setting. On a TV, the weak point will always be the power source. You will have to connect it normal, the only thing we have is, that by now, we have more experience and we can if something fails, face and start again. it would take a 110/110 transformer to keep the input voltje stable. I hope this best of health, receive a cordial greeting from all of us who work here, we are really happy with your achievements. Regards.
23
hace 5 años
Good evening friend Felipe! How are you? ... in terms of health because if I have been better, thank you .... in terms of experience in this type of TV because if I have managed to acquire great knowledge thanks to the support of you and your colleagues, I also I thank fellow Jose Antonio for participating in comments on the failure of this TV ... Well, if it will be tomorrow to put it live, since the TV I leave it in a place where I work and in my house I was doing other tasks with a strip of leds of a tv of leds .... as soon as you verify the total operation of the tv I will close the subject ..
23
hace 5 años
It is possible to say that this has been my first great experience in this type of forums and until now it has been very pleasant and frutifera, although I do not know the total of the rules of this forum because I wanted to know if the only way to continue communicating with you is to Through only this forum? ... I have noticed that to place photos and diagrams you must have an experience of participation in forum topics or it will be that I do not know how to work ... well if you know how to guide me in this I thank you before to terminate everything on TV .... I will be testing it and inform you ... thanks
2.308
hace 5 años
Mr. Luis.- As for the rules and rules of the Forum, I only know the most elementary, (not to mention religion, politics, offer services, or ask for payments, place mail, etc. etc.) .- It barely has a couple of months I learned to send the photos. (I still can't post videos). Hopefully the TV works satisfactorily. Believe me that it has been pleasant to accompany you in this repair and learn from you.- It is good to know that you are in good health, and it will always be a pleasure to greet you.
hace 5 años
hace 5 años
Good afternoon, check the output of the auxiliary winding of the chopper which feeds the integrated circuit of TEA1506T, after starting, remember that this circuit according to the plane of the TV, starts using the auxiliary voltage of the standby source, this voltage is present only at start-up, then it is replaced by the auxiliary voltage, if it is not present it is not enough to maintain enough charge in the 2515 vcc (on) capacitor and the integrated stops operating and enters an on and off process. regards
2.308
hace 5 años
Mr. Joseantonio.- First thanks for participating and joining the problem we have. Now I would like your opinion about the diagram I sent to Mr. Luis, a diagram that appears as: clip and source test2.- I am of the opinion of placing an external b + and taking the sensing transistor to an operation point that allows us to show how much voltage Turn on the external LED, and if it is working.- Greetings. Felipe ascencio
23
hace 5 años
thanks to mr. Jose Antonio for this great contribution to the resolution of this failure of the main source of the TV, because although I already measured that part of the circuit because I have not yet managed to know the specific fault, what I observe is that the source of feedback through the winding Auxiliary (2 and 3) has a very low value compared to the plane and covered with the starting source (9.5VDC), which should not be normal for the total functioning of the ASD. Check components and the only thing I see so far is that the resistance that connects this source through the auxiliary winding (R 3511)
23
hace 5 años
Note that this resistance 3511 is a bit undervalued, the tester measured a value of 5 to 5.1 ohm and the value marked on the plane is 4.7 ohm, because although it is a bit devalued as it seems an acceptable value, since this resistance It is used there as a fuse type in case of short or high consumption .... I do not know what you think of this particularity found in this resistance, I do not know if the choper coils will have to do with all this failure also because the voltage is as dropped for the first starting pulses of the circuit in TEA 1506t
2.308
hace 5 años
if you place the b + variable on pin 4 of the chopper, and on pin 5 the flyback tester hot, connecting a diode with its filter on pin 2 we can check if the output of pin 2 can supply enough voltage to maintain
2.308
hace 5 años
and supply pin two of tea 1506.- I send you a diagram to analyze. greetings everyone.
23
hace 5 años
It seems that the tests carried out on the TV have caused damage to this mosfet again, the previous mosfet was tested with this circuit and it also seems to leak when it is triggered by G and does not keep LED on, an IFR mosfet was placed in this test code and when firing G because the led stays energized, I don't know if this is the best way to test these power mosfet, but they seem to be failing. It is possible to say that initially this mosfet was detected with leaks and TSH in short and for that reason it was changed but the TEA came to change it was after several tests and although its operation seems to be ..
23
hace 5 años
... the operation of the new TEA1506T seems to be the same as it was originally installed. I have heard in several posts that when one of the main components of this source is damaged, sometimes it is necessary to change them all at once, including the optocoupler together with the ASD and the mosfet and I do not know if it was the most advisable, because in My case only installed the mosfet that in my opinion was leaking in measurement and after several tests done because the ASD and the opto were changed but now after measuring mosfet again it seems to be leaking
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