LG 50PA550 - No picture (95% of the time), has sound.

[acklac7]

Greeting all, trying to repair my mint-condition, dumpster-recovery LG 50PA5500 for the second time. First time around it was a high-pulse capacitor on the main power board, this time i'm a little stumped...

Symptoms: TV slowly but surely started displaying no picture, but always has sound. At the point now where it will only display a picture 1/75 times I power-on. Once it powered on it will display a picture for days.

Interesting observation: If the room temperature is below 50 degrees, and the unit has been powered off for more than 4 hours, it will initially display a picture 90% of the time. Again, once the display comes on, it will stay on for days. You turn it off a minute after you get it to turn on? It acts up and won't display a picture for hours and hours.

Figured it was the caps, but the caps don't look all too bad? Maybe some ever so slight bulging on a few, but nothing eureka-inducing.

Thoughts?

[tvtimmy]

Re: LG 50PA550 - No picture (95% of the time), has sound.

Pictures of your tv and hoards help us help you.

[Nick's Tvs]

Re: LG 50PA550 - No picture (95% of the time), has sound.

Check for cracked solder joints on your power supply Y-sustain and Z-sustain. Those can and will cause the symptoms you are experiencing.
One thing you can do to rule out your main board however, is to remove the main board from circuit completely and jumper the auto exe gen holes together. If the color pattern test comes up no problem everytime then main board is at fault. If you are unable to get pattern test then main board is not causing the fault.

[Nick's Tvs]

Re: LG 50PA550 - No picture (95% of the time), has sound.

Check for cracked solder joints on your power supply Y-sustain and Z-sustain. Those can and will cause the symptoms you are experiencing.
One thing you can do to rule out your main board however, is to remove the main board from circuit completely and jumper the auto exe gen holes together. If the color pattern test comes up no problem everytime then main board is at fault. If you are unable to get pattern test then main board is not causing the fault.

[acklac7]

Re: LG 50PA550 - No picture (95% of the time), has sound.

Check for cracked solder joints on your power supply Y-sustain and Z-sustain. Those can and will cause the symptoms you are experiencing.
One thing you can do to rule out your main board however, is to remove the main board from circuit completely and jumper the auto exe gen holes together. If the color pattern test comes up no problem everytime then main board is at fault. If you are unable to get pattern test then main board is not causing the fault.

I've reflowed cold soldier joints before with pretty good success on various automotive applications. Guess i'll give it a shot.

Will post pics when I decide to turn the TV off, probably going to be a bit.