WS-65907: Long time convergence issue, then light on and dead

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YouBetcha
WS-65907: Long time convergence issue, then light on and dead

The convergence on my WS-65907 had been jumping in and out for a few years (a whack on the front would get it back in), so I thought I would be changing/resoldering the convergence IC's at some point. Well, it finally died with the "green light for 3 seconds then off". Service Code check is showing a "short protection circuit". I read posts here indicating convergence IC's can be the culprit in tripping this code.

The threads here have been extremely helpful. I have the board out. The resistor bank above IC8C01 was covered in oil (I assume from one of the caps), and the board under jumper wires (?) 7 and 19 were heavily scorched, but continuity checked fine. Per a post I read by Larry Dillion, I identified that picofuses F9A04 and F9A05 were both blown, leading me to believe the convergence IC's were the root cause. Everything on the IC8C02 side looks fresh as a daisy. All of the 3.9 and 150 ohm resistors are testing OK.

I've ordered two STK392-570 replacement ICs, picofuses to replace F9A04 and F9A05, and two new capacitors for C8C03 and C8C05 just to be safe in light of the mysterious "oil spill".

Any thoughts or words of wisdom before I start putting this all back together? The scorching around those jumpers is not something I had seem mentioned in any threads, and I'd hate to burn up two new IC's!

Thanks!

YouBetcha
Update... Two pico fuses, two

Update... Two pico fuses, two capacitors, and two convergence IC's installed. Works like a champ! I even found the loose connector pin that was likely the cause of the original convergence issue. Thanks to all the experts that posted various tips on diagnosing Mitsubishi big screen issues.

Thanks again!

 

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