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Samsung CL21M40MQ TV does not turn on

ismael0620
hace 5 años
hace 5 años
Greetings dear friends, I hope you can help me with this problem. I have in my possession a Samsung TV Model CL21M40MQ Chassis: KS9C , which does not turn on, when performing the review I found Fuse blown, diode D804s , diode Dz803 , counters C813 , C306 that were embedded and the regulator Ic801 5Q0765RT short between 2y3 legs. I replaced all those components and when I turned on the TV, the lamp illuminates. I can't find another defective component, browsing Google I found that the burned PTC could cause you short and was tested by removing the cable that goes to the screen to demagnetize it and if it didn't give you short the problem was the PTC, I did that test, remove the cable and the short one disappeared and I told myself is the PTC change it for a new one and nothing follows the short one when I connect the cable that goes to the screen and if I disconnect it that cable is lost the short one Voltage measurements when I disconnect the cable so it doesn't cut short. main filter voltage: 320v voltage at + B: 10v voltage in Ic801 in stamby pin1: I don't get reading as if it were infinite pin2: 0v pin3: 12v pin: 4: 0v pin5: 0v This regulator makes me distrust that it is NOT good because it is not new, I will buy a new one but it is possible that this regulator will produce this short. I am not a Technician but I have knowledge about electronics and already make other repairs such as tv and fast. I look forward to your help Thank you..
Yunior Delgado Blanco
hace 5 años

Upload the diagram if you have it .... greetings

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ismael0620
hace 5 años

here the friend diagram although there are components that do not match look fed up on the web and all have the same diagram for this KS9C chassis
https://elektrotanya.com/samsung_cl21k40mqgxxaz_chassis_ks9c_n_ray.pdf/download.html
wait for upload to download later
example I burn the Dz803 diode on the card has the ZP27 according to datasheet is 27v but in the diagram it indicates that the Dz803 claims to be 1N4742A according to datasheet is 12V, as well as the capacitors.

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nicomena2015
nicomena2015
9.501
hace 5 años
hace 5 años
hello colleague: how many wats is the lamp q, do you have in series between the tv and the power grid ...? .. you must have a minimum of 200w ... since, if you have a lamp of less watts it will turn on to full and q, the ptc takes high intention when turning on the TV ... and can give the idea that, there is a short ... put a lamp of 200w or two of 100w in parallel and disconnect the demagnetizing coil and turn on the equipment and take voltage C812 and see what tension it has both in stand-by and power ... what, says on the lc801 (ka5q0765rt) says that, in pin 1 there is no voltage that can not be through the chopper enter 300v q, goes to pin 1 of the lc801 ... check continuity between pin 1 of the chopper and pin 1 (drain) of the lc801 ... greetings !!
ismael0620
hace 5 años

Greetings friend nicomena2015 on the 100w use serial lamp and also change it for another of 200w and it also illuminates and illuminates just connect it to the mains without turning on the TV, I will see if I can take voltage measurements in C812 in stand- by and in power and on the ic801 if I think it is wrong as indicated I will change it for a new one and if there is continuity between pin1 of the chopper and pin1 of the Ic801

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edson tejada dominguez
hace 5 años
hace 5 años
most likely your regulator is bad disconnect masB and check voltages if you noticed change regulator and comment or but also disconnects masB and at that point place the focus one on the ground and the other on masB comment results
ismael0620
hace 5 años

Greetings friend Edson Tejada and if it seems that the regulator that I put to him that was of equal use was wrong, I will change it for a new one after that I will perform the tests that you indicate.
you tell me disconnect + B how do I do that friend? and when you disconnect + B from how much W would put the focus to perform the tests

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nicomena2015
nicomena2015
9.501
hace 5 años

hello: if the lamp turns on fully, it is xq, you have short in the source regulator or short in the rectifier bridge ... remove the (5q0765rt) and see if the lamps no longer light ... if it continues in them check the bridge rectifier and line filter ... you have a short in the primary ... ok

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nicomena2015
nicomena2015
9.501
hace 5 años

look: seeing your comment you say that, you have 12v on the pin 3 x the doubts with the tv off it measures the D805-813-807-806-in direct and in imbersa to see if there is no diode in short ... ok

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ismael0620
hace 5 años

friend remove the 5Q0765RT and follow the short after connecting it to the mains, check the rectifier bridge diodes and they are fine also check what you told me D805, D813, D807 are fine D806 does not exist on the card.
What confuses me is why? When I disconnect the cable that goes to the screen to demagnetize it and connect the TV to the mains there is no short.
what else can I check friends maybe something I'm ignoring.
Thank you for your prompt response. I will listen to your advice.

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nicomena2015
nicomena2015
9.501
hace 5 años

look colleague: the ptc takes a lot of intention at the time of turning on the equipment ... I already tell you more arriva ... remove the ptc from the circuit since q, this ptc is for another function ... it has nothing to do with the function of the source ... remove it from the circuit and give power and see if the lamps now turn on and off, it is straightforward ... or there is no short ... ok ..

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ismael0620
hace 5 años

Greetings Dear, a thousand apologies for not responding, I was sick but we continue with the TV fight.
I wanted to tell you that as you know I have a short in source and check rectifying diodes and they are fine, the R804 and R801 of 0.68ohm 2W is overheated, I decided to remove these resistance and the Ic801 was still wrong and I removed it, I also decided to remove the 4 diodes rectifiers, then I decided to connect it to the electricity network thinking that some of these that I removed were wrong thinking that when they were energized they fail, but it was not that way there was still the short film without those components.

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ismael0620
hace 5 años

I still haven't removed the ptc, friend nicomena this will be the problem although this ptc is new, it was the first thing I did

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nicomena2015
nicomena2015
9.501
hace 5 años

look friend: remove the ptc from the circuit as I explained ... remove it once if we are not always in them ... more if you are using a lamp between the TV and the electric network x more q, be 200w will turn on when the power is turned on but for a few seconds and then it has to go off ... to repair the source, remove the ptc if or if ... I don't know if you understand it, colleague ... and once removed the ptc energize the tv and the rectified line voltage should appear on the main capacitor of 300v or 165v according to the mains voltage q. have ...

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ismael0620
hace 5 años
hace 5 años
Greetings dear friends I apologize for the delay, I was busy in other matters and I did not have time to continue with the repair until today, thanks to nicomena2015 for his constant help and it was as he said I extracted the ptc and started working without him, where the TV was trying turn on and protect yourself by observing in other forums and to the concrete response of friend Joansoler that this protection was due to the CR404s 681k 2kv and that was how the change was made and the TV remained operational. Thank you all for your help, until next time. [url=/ver-adjunto/aHR0cHM6Ly9jZG4ueW9yZXBhcm8uY29tL3VwbG9hZHMvZGVmYXVsdC8wMDAyLzY4L2tzOWMtODU3NDYuanBn] [img] /jp/bng/bng/bt/bng/kta/atta.png/kat/stap/bng/bt/bng/bng/bng/bng/bng/bng/bng/kt/bng/bng/bng/bng/bng/bng/bng
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