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Sharp LCD tv: LC42D72u

 
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PostPosted: Thu Sep 17, 2009 4:02 am    Post subject: Sharp LCD tv: LC42D72u Reply with quote

It has the green opc/power flashing light problem. The power and opc light flash 2x together (1 second) and then the opc by itself for 3 flashes. Looking it up online suggests it's a power board problem. When the unit is plugged in it immediately clicks and about 2 seconds later it does it again.

If I press the channel- and volume+ (service mode) I can see the backlight for the screen but no main display (no letters or text at all). When I do this the main board has a solid and a flashing red light (didn't look up the board or light).

I replaced the ps-board (LC605-4001CC,RDENCA184WJQZ) and the issue is still happening with the replacement board. Both original and replacement boards look good, no bulging caps, no cold soldier joints (re-tinned the ends of the original just to check). If my eyes were what they were years ago I'd check the etches better... but they all look good as they do against a bright light looking through them. My thought is this would be inverters since I can get the backlighting in service mode, but no more. Without knowing what the outputs should be I really can only guess.
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Dan the Tv man
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PostPosted: Sat Oct 03, 2009 4:51 pm    Post subject: LCD/no pic Reply with quote

If the inverters were bad you would probably have sound.I would say that the panel is overheating and shutting the power supply down.
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minnie



Joined: 18 Aug 2005
Posts: 2877
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PostPosted: Sun Oct 04, 2009 4:12 pm    Post subject: Reply with quote

Pull the inverters off and find out which contact is bad. It's plastic tabs that stick up with a metal strip in it the strip carbons up and shuts the set down. Sand paper of a fiber pen cleans the strip. I just did one where the contact was so bad it ate through the inverter board!
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