Lg Plasma TV problems

[iadrian]

Re: Lg Plasma TV problems

Of course, I am just afraid of scenarios like big explosion and similar .

WOW, that is high speed !

I`l do that now and come back with info in approximately 20 minutes.

Thanks!!!

[tom66]

Re: Lg Plasma TV problems

You can see my thought process for this repair on a 42" LG, with a slightly different power supply and complete refusal to power up:
https://www.badcaps.net/forum/showth...ghlight=42pc1d

and many others with a similar problem.

[iadrian]

Re: Lg Plasma TV problems

Ok. I have done as you said.

Good thing is nothing exploded .

The TV turned on and everything looks fine.

I will test it and come back when I have new information.

Thank you !!!

[iadrian]

Re: Lg Plasma TV problems

I have turned it on and off for 40 times and it works!

It looks like this solved the problem!

Why does this problem occur? What is that AC check for?

[tom66]

Re: Lg Plasma TV problems

I'm not 100% certain on what is going wrong, but my theory boils down to this:-

The AC detect circuit is there to monitor AC power input and see if it is stable and to make sure the set can operate properly. It needs to work from 100V (160V DC) to 250V AC (360V DC) so has to have a wide range.

So it probably detects any signal beyond around 80-100V DC as being good. As mains surges/transients* and time goes on the reference circuit drifts. Over time maybe it eventually wants 350V DC to work (after it has drifted and got worse and worse.)

Your AC line voltage varies over the day, with load on the neighbourhood, grid demand, local household load etc -- basically appearing random to the average person. Slight variations prevent the set from always working. but in a seemingly random way.

*Transients: around 5~10 per day in excess of 500V AC typically up to 1000V AC. Few if any surge suppressors actually suppress this.

[iadrian]

Re: Lg Plasma TV problems

I understand.

Thank you a lot and if I can do anything for you just ask!

This TV was doomed to the trash because nobody in my city could fix it. And the last "TV guy" said it can`t be repaired.

If the problem reoccur I will contact you but I think this repair did the job.

Greetings!