LG 60PA5500-ug won't turn on

[bushwoodj]

Hi All,

Been lurking the last couple of days trying to find some tips on how to fix a LG plasma I just received. Set was made in 2012, and was apparently working fine until I received. Set it up, turned it on and it worked perfect for 15 minutes then turned itself off and now will not come back on. Tried hard reset and nothing.

Basically, when I plug it in I hear a click and the front red led stays lit, but neither the remote nor set power button does anything, so I'm thinking it is stuck in standby mode as it looks like the screen is somewhat backlit(hard to tell during the day with the room being so bright).

I have taken off the back panel and inspected for any obvious capacitor issues, which appear to all be good. The main board red led is on. On the logic board the green LED is flashing, long, short, long, short. Have disconnected the Y and Z boards separately and nothing.

Any thoughts on what I should try first before I start replacing boards(which don't look too readily available)? I am a total noob when it comes to tvs having only tinkered on old radios and other electronics years ago but not afraid to try replacing individual board components.

Thanks in advance!

[bushwoodj]

Re: LG 60PA5500-ug won't turn on

Pics of boards

[mmartell]

Re: LG 60PA5500-ug won't turn on

Bad solder joints under the y sustain. Check the large components on heatsinks but especially the transformer joints.

[bushwoodj]

Re: LG 60PA5500-ug won't turn on

Thanks, I'll check those specifically tonight and report back.

[Andrew F. Ali]

Re: LG 60PA5500-ug won't turn on

The 'click' is the PSU relay turning on. Does it click once or does it double click? This is an indication that the PSU is OK. Do you know how to self-test these PSUs? I would however think that you have a Y-sus Bd. issue.

[bushwoodj]

Re: LG 60PA5500-ug won't turn on

It only clicks once when first plugged in. After that, the front led remains on, as well as the main board one.

I'm not familiar with the self test for the psu.

[Andrew F. Ali]

Re: LG 60PA5500-ug won't turn on

Here is the shortcut method since the relay clicks on and stays on. Connect 2-120Vac light-bulbs in series to make a test-lamp. Disconnect P811 (The picture is a bit dark.) the connector with Vs and Va and M5V from the PSU. Connect the test lamp across the Vs and GND pins on P811. Plug in the TV to the ac and switch ON. If the PSU is good the test-lamp should come ON bright and stay ON. WRT chassis GND measure M5V and Va, they should be spot on telling us the PSU is working.

[aaronwt6]

Re: LG 60PA5500-ug won't turn on

If the red light stays solid and does not flash when the remote or power button is pressed, you most likely have a main board issue.

[bushwoodj]

Re: LG 60PA5500-ug won't turn on

So, I found another thread about doing the screen self test. I was able to do it and it did bring the screen on and appeared to run it properly.

Does that basically mean my main board is definitely the issue?

[tvtimmy]

Re: LG 60PA5500-ug won't turn on

Yes

[Andrew F. Ali]

Re: LG 60PA5500-ug won't turn on

Yes

+10
and the PSU is OK

[bushwoodj]

Re: LG 60PA5500-ug won't turn on

Great, found a board on eBay and hoping it works!

[Andrew F. Ali]

Re: LG 60PA5500-ug won't turn on

Update us when you get and try the new Main Bd.

[angelos]

Re: LG 60PA5500-ug won't turn on

So, I found another thread about doing the screen self test. I was able to do it and it did bring the screen on and appeared to run it properly.

Does that basically mean my main board is definitely the issue?

Can you tell me how you did the screen test

[tvtimmy]

Re: LG 60PA5500-ug won't turn on

Unplug the ldvs cable that runs from the mainboard to the logic board. In that area there are 2 holes marked EXT_AUTO they are under r651 and r652. Put a bent paperclip or a piece of wire in each hole to short them together. Turn on tv and look for solid colors and then test patterens on screen.