LG 50PA6500 and repairing Y-Buffer board

[RethoricalCheese]

So I got this TV to fix. First plasma I have ever owned thus first plasma I have tried to fix.

Isolated the problem - upper Y-buffer board is faulty. To be precise, the most upper buffer R2A20299FT is the culprit. Checked the flex cable too and that seems fine to me. Disconnecting upper buffer gave me a nice picture at the bottom part so Y-sustain and bottom Y-buffer seems to be in good health.

Searched for a new board but because I am a poor student, I would not like to pay around 50€ for a whole buffer board. Thus I decided to just buy the ~10€ new buffer IC and replace the faulty one. I consider myself very good at soldering so it shouldn't be a problem.

Just to be sure, I tried to search for a topic where somebody has tried it but couldn't find any.

So my question is - Has anybody tried it and what should I pay attention to?
Should I reapply the silicone after soldering and cleaning? What kind of silicone should it be?
And finally, should I place a heatsink on it so it wouldn't die so easily again?

[keeney123]

Re: LG 50PA6500 and repairing Y-Buffer board

So there are many people on here that are much better at understanding these units as they work with them every day. So I am sure one of them will see your post and reply. If not I will try to help the best I can.

[RethoricalCheese]

Re: LG 50PA6500 and repairing Y-Buffer board

Found only one video on youtube and looks like there's nothing really to pay attention to. Just a normal soldering procedure.
And seems like hot glue is the way to go after soldering

Anyway, I will order a new buffer soon and whenever it arrives, I will try to document my work on it and post it here for others.

[keeney123]

Re: LG 50PA6500 and repairing Y-Buffer board

Hey, I will be interested in what you find.

[dick_barton]

Re: LG 50PA6500 and repairing Y-Buffer board

I used an old credit card cut into strips and used that to peel away the soft glue around the chip.
Also heat up the bottom of the chip from the underside of the board because the IC is probably soldered to the copper pad beneath it. I used a hot air station to then remove the IC applying plenty of flux before starting. That removed them really well.

[RethoricalCheese]

Re: LG 50PA6500 and repairing Y-Buffer board

Oh damn, sorry to disappoint you but looks like it takes too long to ship those IC-s so I just have to resell the TV.
But whenever it's a more appropriate time financially and I get another plasma with such fault, I will be sure to do what I promised.

[keeney123]

Re: LG 50PA6500 and repairing Y-Buffer board

Oh damn, sorry to disappoint you but looks like it takes too long to ship those IC-s so I just have to resell the TV.
But whenever it's a more appropriate time financially and I get another plasma with such fault, I will be sure to do what I promised.

Where are you buying them from?

[RethoricalCheese]

Re: LG 50PA6500 and repairing Y-Buffer board

If you mean the IC-s or other parts - well... anywhere I can find them. In this case there aren't many sellers and all are located in china which mean they won't arrive before Xmas.

In this case, Aliexpress looked like the best place to buy from.

[syaoran123]

Re: LG 50PA6500 and repairing Y-Buffer board

I have this TV as well and keen to try some component repair. But first, how did you work out which buffer IC was the culprit? Is there a way to test with a multimeter? I already tried probing along the ribbon connectors and checking for shorts with GND, but it doesnt beep.

Oh btw...I found this thread:
https://www.badcaps.net/forum/showth...4338&highlight

[RethoricalCheese]

Re: LG 50PA6500 and repairing Y-Buffer board

At first try the input connector and see if it is shorted.
If it is then one probe on input GND, other one on the flex pins or IC pins and see where it beeps. Or just try probing flex pins which are next to each other.

There might be only a couple pins shorted so it might take some time to find them. Start from top side IC.

[syaoran123]

Re: LG 50PA6500 and repairing Y-Buffer board

Yep just saw a video on Youtube on how to test. Confirmed that my top buffer, top IC had shorts which is very common.

I also physically inspected the respective ribbon cable by removing the bezel. Turns out there was a very fine tear on the ribbon. It looks like a crease, but then I pushed my finger thru it with moderate pressure, and the tear got bigger...so that backs up the theory.

[keeney123]

Re: LG 50PA6500 and repairing Y-Buffer board

If you mean the IC-s or other parts - well... anywhere I can find them. In this case there aren't many sellers and all are located in china which mean they won't arrive before Xmas.

In this case, Aliexpress looked like the best place to buy from.

It make sense to make them in China because that is where the TVs are made.