LG 42PC1DG Plasma picture fault

[dkneyle]

At start up there are a range of sparkle screens in a variety of colours which rotate through about every ½ second. You can see an image but it is as if it is out-of-sync. Jumps all over the place and fairly torn in appearance. Intensity seems low.

I'm sure one of you plasma experts out there can direct me as to the the board which would have failed causing this sort of dodgy imagery.

[maxvalutech]

Re: LG 42PC1DG Plasma picture fault

Control board or connection first choice.

[Sevenqi]

Re: LG 42PC1DG Plasma picture fault

Jumps all over the place --Do you mean the "No Signal" menu bar jumps ?
adjust the VSRs on the y-sustain board to see if you can get rid of the sparkle (Mark the original position before adjustment)

[maxvalutech]

Re: LG 42PC1DG Plasma picture fault

Yes is this just at startup or ongoing and is menu accessible?. My info is low esr SMD caps on control board can be a problem and it is important for all voltages shown on panel tag to be basically within 1v being Vs Va Vsc Ve normally plus all connectors cleaned and reseated correctly. If menu available then reset to original specs.

[dkneyle]

Re: LG 42PC1DG Plasma picture fault

Thanks for all the pointers guys. I'll open it up and have a good look around. And "yes", the "No Signal" jumps all over the place, but is also quite torn in appearance; not a nice neat rectangle. I took some video and if I have no luck with the advice to date I'll post the video on YouTube. I haven't even pulled the back off yet; given what you say about sensitivity to voltages I wonder if it might be a power supply issue. Got a Sammy Plasma back into service in the weekend that had the old bulged capacitor problem. Some vintage set so maybe I'm looking at a similar issue.

[dkneyle]

Re: LG 42PC1DG Plasma picture fault

I've taken the back off and nothing jumps out as obviously wrong. Damned thing is built like a battleship. I've measured Vs and Va and they are spot on. I've posted a video here demonstrating the effect I'm getting: https://youtu.be/wib4Jfc5PiY

Any immediate impressions of what the likely fault is much appreciated.

[aaronwt6]

Re: LG 42PC1DG Plasma picture fault

X-Main ZSUS board failure in my opinion. The jagged, or 'torn' images you are describing are exactly what you'd expect with that failure on this model. Its an X3 based plasma. Check the fuse on the ZSUS board on the right looking at the TV from the back. It will almost certainly be blown.

[aaronwt6]

Re: LG 42PC1DG Plasma picture fault

I watched the video you posted. I'd question a YSUS problem as well the way it's strobing but start with checking the fuse on the ZSUS first.

[dkneyle]

Re: LG 42PC1DG Plasma picture fault

Fuses on X-Main Z-Sus all check out OK. There's two 4 amp cartridge types and two SMT types, all located on the bottom left hand corner of the ZSUS board.
I too was wondering if it was more a Y-Sus problem? Other than a board replacement not too sure what to go looking for or testing on the Y-Sus board?

[dkneyle]

Re: LG 42PC1DG Plasma picture fault

After having a PM conversation with TW2005 I decided to canabalise the TV. It has those dreaded IPM chips and I'm pretty sure it was a Y-Sus failure.