Tv philips 20pt324b with audio without video
Good afternoon: If you cannot see the brightness of the filament in the neck (Heater), you can measure it with DC in the tester, you have to give a reading of approximately 6 volts. Only with an oscilloscope can you see clearly its voltage and signal, (I think it is 27 Vpp. Look for diagrams from the WEB. You can check resistors, cut tracks, false contacts, this has to be done from the MAIN board to the small board of the TRC. (I think you can speed up the screen a little to see what happens)
Hello friend, thanks for the help I tell you that I tested with an analog tester and a half 5v dc until the crt plate the neck was very dirty so I could not see what was going on, with this I know that it is not a filament problem, I'm going to keep looking for what I find. regards
Hello friend, now you don't do it anymore I don't get the image when I change the channel, but you're right when I did the color was out of adjustment, I will verify well and then comment again.
thanks to everyone...
Apparently they are fine on the 3 pins of the tube rgb I have equal tensions 202v dc v14 v15 v16 I also tried another original eprom of the plate that I have and nothing ....
but if you have 202v, then there is no consumption in the video output transistors; there must be between 120 and 140v at each cathode. I measured at the bases of them there should be around 2v in the three transistors. The one of the 3 diodes 1n4148 that I mentioned to you is so that the TV does not turn off even if the tube cathodes are exhausted.
This TV has 3 tube transistors per color on the socket plate. The voltage of around 2v or 2.4v that I tell you in the bases you must measure in transistors 7331 (blue), 7321 (red) and 7311 (green) and arrive from the jungle. If they are not working the other 2 transistors in each color and there is no consumption so you have 202v in each cathode instead of about 140v
Good morning....
Thanks for continuing to help me, I'm going to try another tube now to get out of doubt .....
Now I tested a tube of a philco and it has no brightness so it is not that the tube is exhausted, I measured the bases of the transistors and there is no tension in them either in the jungle pins, this wants to say that the fault is in the jungle jungle?
Regards.
when you said that by changing the channel, the image came out (with mismatched colors) indicated that the tube could be wrong and that is why it went out (IK); but then you said that no image came out yet changing the channel and you also didn't have the 2.4v tensions in the bases; This can be a problem of the TDA8844 jungle (7250 cerigraphy). Measure the tensions in it. If you retouched any welding in the same verify that you have not made any bridge with welding.
The TV turned off only when the image appeared now with the black screen does not turn off, well I tell you what I did, I did the procedure of the LED flashing to see what the mic indicated, it worked started a series of flashes that shows the protection code 6 and 12 indicating problem in the crt stage then proceeded to change the crt board got a good condition of the same chassis but 14 inches, the result was that there are no changes I still have a black screen, now I will proceed to change the jungle ci aver what happens then comment ...
you're getting complicated I think
a question what voltage do you have on grid that comes from the fly back
I think if my friend, I turned it from end to end, right now I changed the jungle and nothing to solve, what changed was that when you raise the escrem you see some shine with lines you mean the tension of the filament It is 5vdc.
Well guys I tell you what happened, after changing so many components without success, I began to think and use a little reasoning and logic that I think are fundamental in electronics, which had happened on this television, as I mentioned at the beginning I had the perforated plate, and singed, for this to happen there was a lot of tension near the hole, logically there would have to be more damaged components, I started to check the resistance values and EUREKA !!! I found 2 open, which are the r3407 220r 3404 12k one is connected to the horizontal coil
Very good that you found it. It is best to always work with the circuit and measuring. That burnt R 3402 (12k) sends the horizontal pulse of the flyback (Hflybk) by A7-32 to A4 to pin 41 of the jungle 7250 (tda8844) and also to A7 by A32 to the base of transistor 7610 and the collector from east to pin 37 of micro 7600 (SAA5565P).
Thanks Mario and I want to clarify why I am wrong the resistance that the Hflybk pulse is the 3404 (12k) and not 3402 as I put and the 3407 is the one that takes the 95v (+ B) and goes to the def coil. Horiz Regards.
No thanks to you for the clarification now I have it written down, for me it is important to learn to interpret the circuit knowing its operation facilitates the repair I almost found the fault before I was to measure the transistor 7610 and I did not hehehe ..
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Curso Refrigeración Comercial Aplicado a Diagnóstico y Reparación
