Hi,
I have build up again a defective SC-board TNPA5335 with all! IGBTs and several drivers and other components, after incomplete 6 blink repair and further issues. Finally I got the board almost to work again, running now at least for some minutes without shorting down.
Anyway, something is still wrong, I guess but not 100% sure that it is on the SC-board.
Latest step before now was sparkling all over the screen, then Q16820 was replaced and situation now is this. Also to say that Q661, IC921 and other parts for Vad have been replaced too, not only Q401-3 and Q421-3 as usual.
As said, set is running up without failure mode and screen appears. Upper half is extremely bad, but also light sparkling can be seen on bottom part plus brightness problem, see pictures for test patterns. Strange to me all patterns show the problem except clear colours (RGB). See blue and also color bar.
Vad (200V) and Vscn (147V) looking good for me.
I did some scope testing for Vscn, but found nothing strange, but I'm not expert in that and may oversee something.
Needless to say that i checked all components that seems relevant to me, twice.
Any help to identify the defect is welcome. It might be not SC-board, but I have no idea what else it could be.
regards,
Dieter
I have build up again a defective SC-board TNPA5335 with all! IGBTs and several drivers and other components, after incomplete 6 blink repair and further issues. Finally I got the board almost to work again, running now at least for some minutes without shorting down.
Anyway, something is still wrong, I guess but not 100% sure that it is on the SC-board.
Latest step before now was sparkling all over the screen, then Q16820 was replaced and situation now is this. Also to say that Q661, IC921 and other parts for Vad have been replaced too, not only Q401-3 and Q421-3 as usual.
As said, set is running up without failure mode and screen appears. Upper half is extremely bad, but also light sparkling can be seen on bottom part plus brightness problem, see pictures for test patterns. Strange to me all patterns show the problem except clear colours (RGB). See blue and also color bar.
Vad (200V) and Vscn (147V) looking good for me.
I did some scope testing for Vscn, but found nothing strange, but I'm not expert in that and may oversee something.
Needless to say that i checked all components that seems relevant to me, twice.
Any help to identify the defect is welcome. It might be not SC-board, but I have no idea what else it could be.
regards,
Dieter
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