Lg 42pc3d

[drpj23]

Ok, so I have the sound no picture issue with this tv.

I plugged it in, let it sit on, and felt the sustain boards and the Z was cold compared to the Y. So I replace that. Same issue.

Well on each board there was a bad fuse (you'll see in the pictures the ones missing which were the ones that were bad)....unless these are bad or not there, then the power supply clicks off. In order to get the previous issue (sound but no pic) there must not be a fuse in both or both sustain boards be disconnected from P/S.

All voltages are right from P/S.

Any thoughts?

[TechShui]

Re: Lg 42pc3d

A blown IPM in either sustain board will cause your power supply to go into protection mode.

If the new Z-sus is actually functioning properly, then you should be able to disconnect the Y, leave the Z-sus (with fuse) plugged and get the TV to turn on, with no video.

Right now it sounds like both boards are dead, but lets hope not.

[drpj23]

Re: Lg 42pc3d

doesn't matter which is disconnected from the P/S, it still goes into protection mode but if I remove the fuse for the Vs (186v) side (for both boards) it powers on to the sound but no pic issue.
The old Z sustain would let it power up with 2 good fuses, but the heat sink was cold compared to the Y sustain.

Also, the continuity on each terminal for the fuse holder on the Y sustain for Vs side gives off a reading that goes up then eventually down to 0 and beeps as if you were testing a diode.

[TechShui]

Re: Lg 42pc3d

Did you figure it out yet?

There's a good test guide here for the IPM
http://blog.coppelltvrepair.com/2011...s-ipm-for.html

[drpj23]

Re: Lg 42pc3d

Sadly not, I just parted out the TV and held the parts to the side but thanks for the link, at least I can mark the bad ones.

Overall, I believe both sustain boards went out, though odd that happened.
I decided to part it since the parts would most likely meet the price of the TV and there wasn't a 100% to that fix. But, shall another come in, I have some parts to mess with (or at least I'll have possibly good buffer boards and a controller board)