LG 50PM670s Mainboard turn the set off after 10 to 20 seconds

[faberHH]

Hello everyone,

I have a LG 50PM670s (very similar to the 50pa6500, but with 3D) plasma TV.
Connected to the power supply, it starts with the LG logo and runs for about 10 to 20 seconds with picture and sound, then the mainboard switches off the television and a few seconds later it starts again in a loop, but without the logo, sound or picture.
It is definitely the mainboard! If I disconnect the mainboard and activate the test signal on T-Con, the test pattern will run without problems.
When I heat the mainboard in the top left corner with a hair dryer, it works much longer. I tried to isolate the bug with cold spray to no avail.
I also tried to heat only IC400-IC403 separately. But that has no effect.

Does anyone have any idea what the error is?

Thanks in advance.

[petehall347]

Re: LG 50PM670s Mainboard turn the set off after 10 to 20 seconds

maybe a capacitor ..

[faberHH]

Re: LG 50PM670s Mainboard turn the set off after 10 to 20 seconds

Thanks for your hint, petehall347.
But unfortunately not.
That was my first idea. I forgot to say that I heated the only electrolytic capacitor in this area separately without success. As a precaution, I have now exchanged it. Unfortunately without success

[budwich]

Re: LG 50PM670s Mainboard turn the set off after 10 to 20 seconds

Use a pencil (with erase end) or plastic stick and gently press on the "area of interest" to see if you can cause an "effect" physically, that might be "mechanical related"... ie. crack in board, stress, etc.