Sharp C-1410 no power (smps issue)

[ostlar]

Good news, it is now alive and well. New flyback did the trick, and it works as before.

Did a thermal image of the board, and nothing stands out except for a resistor that is hot (144°C), R623 which is feeding the horizontal circuit that I have been troubleshooting. The voltage drop over the resistor is only 2,2V, so it should only dissipate around half a watt of heat. Resistor in question is rated at 3W. The resistor is elevated quite a bit from the board, so it is expected to be hot. The max operating temperature of 3W resistors are usually from 150°C to 200°C.

I will diagnose a bit further, because I am not entirely sure the flyback died by itself. Could be driven too hard and the heat made it short out internally. The flyback itself and other components does not show any abnormal temperatures. Maybe I am a bit paranoid, but it is better to be safe than sorry.

Edit: just realized I have two other TVs now with the same chassis, so I will do a thermal image of those to compare.