Atypical issue with 42F430S - picture dies after a few seconds
I've acquired a TX-42F430S from a friend. I am having an issue with the unit that doesn't fit the description of the usual problems with this unit. (Users pontrello and captainvintage described similar issues, but I didn't see a resolution to their posts.)
When the unit is plugged in, I get an amber light, as expected. When I press power, I get the Westinghouse logo, and the LED turns blue. The LCD turns off for a moment, then turns back on. It shows the Component video input correctly for about 2 seconds, then turns back off. The LED stays blue, and I have audio. Thus, I'm fairly certain I don't have a firmware issue. It sounds like a bad cap somewhere. We don't have the history on the unit, so we don't know if it used to stay on longer before dropping out. I haven't tried the hair dryer trick yet -- I'm bald and thus don't own one. :P I'm afraid to take my actual heat gun to this thing just yet. If that's safe to do, I'll give it a shot.
I've bought a replacement power supply board on Ebay, and the exact same behaviour occurs. There are no obvious (to me) bad caps on either board. I've attached photos of both boards. There is, of course, a chance that both boards are defective.
I am an electrical engineer -- I have a quality soldering iron, multimeter and oscillocope, but I'm honestly more of a DSP guy than a TV repairperson. I can certainly replace the caps on the power supply, if that's the issue. If so, with which ones should I start? The 470 uF one mentioned elsewhere in this thread?
Thanks for your help!