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Thread starter #1
Hi everyone. I'm beginner in electronics repairing and I need help troubleshooting a tv which isn't "fully" turning on.
The board is a cheap chinese universal kit(check attached images for reference) .

When it came to me it was dead...the fuse was blown and V513 was shorted. Since I couldn't find any other faulty components I just replaced the V513 transistor and the fuse, and only for precaution I also replaced the V512 transistor (I read somewhere else that it's a good practice replace the V512 whenever V513 is replaced).

Then, I powered it up through a 60W series bulb, and bulb lit up for about 5 seconds and then it went off and the tv power led came to live and also the that characteristic noise of when the set turning on. I measured the B+ voltages, and they all tested to be good.

so I reconnected the tube and all the "wiring" . Then again I powered it up through the series bulb but this time it took about a minute for the bulb to go off and that noise again. But the screen never came on, the led went off the series bulb came back on and very bright...and yet the noise continues...like the set is on... So i tested the B+ voltages again, primary and secondary, and they all tested fine...till i got to the flyback transformer (fbt). The pin that should be testing +180V is testing 156V insted.

I soldered the FBT ans powered up the set without the fbt, but still the symptoms remain, power led off, series bulb on, noise on...etc., B+ voltages are how they're supposed to be. picture.jpg 20181009_095557.jpg

Can anyone help by explaining me what are the possible causes and/or where to look for the problem.

Thanks in advance.

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