LG 42PA4500 plasma TV no picture no sound

[dfowler340]

Hello,

I have a 3 year old LG 42PA4500-UF plasma TV that suddenly lost picture and sound, and I was hoping somebody could help diagnose the problem.

When it first happened everything went black and the standby light on the front panel was a solid red. Trying to cycle the power (via remote and/or the push button on the TV) only resulted in the standby light flashing once and then going solid again.

I opened up the back panel and confirmed with multi-meter that the two fuses on the power supply board are ok. I see no other evidence of electrical burnout on any of the boards or components.

Also, now when I plug the power cord back in, the standby light on the front panel does not light up. The only response I get whatsoever is a slowly flashing red LED on the main board.

Any suggestions for troubleshooting? I don't want to start replacing boards without a solid idea as to what the culprit is.

Thanks in advance!

[ReeceyBurger123]

Re: LG 42PA4500 plasma TV no picture no sound

Hello, can you upload some pictures of the boards and the tv please.

[dfowler340]

Re: LG 42PA4500 plasma TV no picture no sound

Hi...pictures are attached, thanks for responding

[Hamie]

Re: LG 42PA4500 plasma TV no picture no sound



Connect the 2 holes marked ext_auto_gen on your control board with a bit of wire. Paper clip etc.

Disconnect the lvds cable (the one with the black tape over it).



Power on tv, if you get test patterns you have a faulty main board.

[dfowler340]

Re: LG 42PA4500 plasma TV no picture no sound

Thanks, I will give that a shot tonight.

[dfowler340]

Re: LG 42PA4500 plasma TV no picture no sound

Hamie,

I tried what you suggested however I still have no picture or sound. As before, the standby light on the front panel stays a solid red and flashes once when you press the power button. No other sounds or lights of any kind. Any other thoughts?

Thanks

[ReeceyBurger123]

Re: LG 42PA4500 plasma TV no picture no sound

Ok, do you have a DMM ?

[dfowler340]

Re: LG 42PA4500 plasma TV no picture no sound

Yes

[Hamie]

Re: LG 42PA4500 plasma TV no picture no sound

Ok unplug this connector here.



Try and power on the tv..

You'll notice also in the above picture there is a wire jumper marked VA-TP
There should also be a similar one marked VS-TP.

What voltage do you get at these 2 test points. You may find the voltage drops after a few seconds, so plug in, turn on, and quickly measure each test point.

Dc volts - red probe to wire jumper - black probe to chassis ground.

Be careful don't short anything out.

[dfowler340]

Re: LG 42PA4500 plasma TV no picture no sound

VA-TP: 1.0 - 1.5 mV
VS-TP: 5.0 - 8.0 mV

In both cases the readings fluctuate within the range I've listed but they never drop off completely.

[Hamie]

Re: LG 42PA4500 plasma TV no picture no sound



Can you measure the voltage on either of these 2 capacitors.
Black probe to the negative leg red to the other.

Post back the voltage.

Also please upload a clear picture of this table.

[dfowler340]

Re: LG 42PA4500 plasma TV no picture no sound

Both capacitors read about 161 volts. Attached is a picture of the table.

[dfowler340]

Re: LG 42PA4500 plasma TV no picture no sound

Hamie - any suggestions for what to check next?

Thanks

[Hamie]

Re: LG 42PA4500 plasma TV no picture no sound

what is the voltage when on the either of the primary capacitors when you press the on button? Does it rise or just stay the same?

[dfowler340]

Re: LG 42PA4500 plasma TV no picture no sound

The voltage on both capacitors remains the same when pushing the ON button.

For what it's worth, both capacitors are now fluctuating between 375-400 V compared to the 161 volts that they were reading the last time I checked.

[jrpitale]

Re: LG 42PA4500 plasma TV no picture no sound

Guyz

I am having same problem with same model of LG plasma TV

Please suggest me to work around in same issue.

Thanks

Jatien

[Andrew F. Ali]

Re: LG 42PA4500 plasma TV no picture no sound

Guyz

I am having same problem with same model of LG plasma TV

Please suggest me to work around in same issue.

Thanks

Jatien

Start your own new thread.....Don't worry if it is the same issue.