Need help troubleshooting LG 50PC3D

[van35]

When you plug the TV on it attempts to turn on. You hear the relay click on the power supply. The light flashes green a couple times and then goes to red. The same thing happens every time you press the power button.

I inspected the power supply board and saw some caps that were bulging. I am not an expert at soldering so i ordered a new power supply board hoping it would fix the problem. But it did not. Same exact thing. I have not been able to get the TV to turn on at all during any of the troubleshooting.

What else can i test to determine which board might be bad before i go and purchase a replacement.

All help is greatly appreciated.

[tom66]

Re: Need help troubleshooting LG 50PC3D

Unplug the Y-sustain (left hand board from rear connecting to plasma panel.) Check if set powers on (with no picture.)

Then plug Y-sustain back in and unplug Z-sustain, which is on the right. Check for DIM picture (blurry or purple tinted sometimes.)

Do all unplugging/replugging with power completely off for 30 seconds (unplug it.)

Do you have or can you get a digital multimeter?

[van35]

Re: Need help troubleshooting LG 50PC3D

Tried that and same result. Nothing appears on the TV at all. Light flashes green 3x and back to standby.

Yes i have a multimeter

[tom66]

Re: Need help troubleshooting LG 50PC3D

OK first step is to post some pictures. I have worked on the smaller brothers of these - the 42PC1D and 42PX5D - so have some familiarity. It could be AC detect issues (as is common with some LG plasmas) - but you probably ruled that out by swapping the whole PSU.

[van35]

Re: Need help troubleshooting LG 50PC3D

Here are the pics.

[tom66]

Re: Need help troubleshooting LG 50PC3D

It's clear the seller of the PSU wasn't telling the truth - that PSU has been re-capped and with inferior Jamicon caps. They could be an issue, cannot be certain but they won't last long anyway. Did you swap the PSU or order a new one?

[van35]

Re: Need help troubleshooting LG 50PC3D

Ordered it from a guy on eBay.

[tom66]

Re: Need help troubleshooting LG 50PC3D

Ordered it from a guy on eBay.

Was it sold as used or refurbished? Who knows if it is faulty - could have same problem, very common with these particular power supplies. Still the fault can be tracked down. If you look at the connectors going to the main board (the one with HDMI on it) you should see some connectors going to the main board. Unplug them to reveal the labels near them and take a picture or list them. You should see one labelled AC-DETECT, AC-DET or AC-D.

[van35]

Re: Need help troubleshooting LG 50PC3D

Here is the link from the one i purchased.

http://www.ebay.com/itm/130748005358...#ht_500wt_1156

What do you want me to do once i find that pin on the main board? The TV is at my office and i will be back there in the morning

[tom66]

Re: Need help troubleshooting LG 50PC3D

Manufacturer refurbished - closer to seller refurbished.

Anyhow, the pin is on the power supply; I'd like you to check the voltage on it. If it drops out when the TV clicks off, the fault is there.

[van35]

Re: Need help troubleshooting LG 50PC3D

OK. When the TV is in standby the dmm reads 4.86. When the TV attempts to turn on it drops to 4.83 and goes back to 4.86.

[tom66]

Re: Need help troubleshooting LG 50PC3D

Seems okay I would suspect your PSU board though; can you get a pic of the solder joints on the caps?

[van35]

Re: Need help troubleshooting LG 50PC3D

Are these pics ok?

[tom66]

Re: Need help troubleshooting LG 50PC3D

The soldering is probably acceptable, but isn't the best in the world.

It would be a good idea to either send the PSU back complaining it is not manufacturer refurbished, or to retouch all the joints - your choice, I think the guy ripped you off, especially at $100 for that part.

Or you can look into main board or control board - someone else here has a 50PC1D with similar issues, and the problem hasn't been figured out yet. Seems like a very tricky issue to sort out.

[jettboat]

Re: Need help troubleshooting LG 50PC3D

I have 2 of these 50" pc3d & pc1d. I got from a guy that tried to repair but he replaced the caps with wrong values (ie. 100uf with 1000uf, 680uf w 3300uf)
then my question is the proper values & locations for the caps on the pcu that typically go 15ea. or so.

this is the start of the issues with both do need buffer top & bottom for 1 as they were missing

[tom66]

Re: Need help troubleshooting LG 50PC3D

Here is one pic it might help, from 42PC1D:
http://www.tgohome.com/Teardown%20Pi...D/DSCN6837.jpg

[jettboat]

Re: Need help troubleshooting LG 50PC3D

I believe the 9 outer left & rt of pic are all suposed to be 3300uf 10v . & the 680uf 50v & 100uf 50v, i can see this helps some but the ones I cant see ?

[jettboat]

Re: Need help troubleshooting LG 50PC3D

I think I got the caps figured out now on this set. but believe more is wrong as vs va ramp up then shut down quickly. Y sus & z sus disconnected still the same.

[tom66]

Re: Need help troubleshooting LG 50PC3D

Check AC detect pin. (AC-DET or AC-D or AC-DETECT)

[jettboat]

Re: Need help troubleshooting LG 50PC3D

got the caps done & It was two fet's shorted got all voltages now so on to the y sus / buffer ic's really makes it tuff when others try to fix the tv with improper componets