LG 50PC3D-UD Screen problems

[crbn79]

So I have a 50 inch LG which I have been trying to get going. I have replaced a bad power supply, a bad Y sus and Y buffers.

Yet I am still getting problems which I thought were a bad Y Sustain board or buffers.

Pictures attached, please help!

[tom66]

Re: LG 50PC3D-UD Screen problems

Perhaps the replacement parts were faulty? It still looks like bad buffer board to me. Did you replace buffer then power up with old Y-sus?

[crbn79]

Re: LG 50PC3D-UD Screen problems

Thanks for the response. These buffer boards just came in the mail and I've only tried them with the replacement Y-sus and replacement power supply.

I am thinking that your assessment on the replacement parts being bad may be accurate. I used to have a .pdf on my laptop which showed the different picture issues and what the issue was, but for the life of me I just can't find it on my computer.

[tom66]

Re: LG 50PC3D-UD Screen problems

Can you try with just the bottom buffer unplugged?

[crbn79]

Re: LG 50PC3D-UD Screen problems

Can you try with just the bottom buffer unplugged?

Yes, just tried, same results with bottom half of screen black.

[tom66]

Re: LG 50PC3D-UD Screen problems

OK, does it behave differently with just the bottom buffer connected?

[crbn79]

Re: LG 50PC3D-UD Screen problems

with the top hanging loosely and disconnected from the metal tabs on the y-sus board it does the original symptoms. Does this mean the problem lay with the top buffer board?

[tom66]

Re: LG 50PC3D-UD Screen problems

Original symptoms?

[crbn79]

Re: LG 50PC3D-UD Screen problems

I'm sorry, same as top 3 pictures. It acts the same as if both buffers are connected.

[tom66]

Re: LG 50PC3D-UD Screen problems

Can you upload a picture of each buffer?

[crbn79]

Re: LG 50PC3D-UD Screen problems

Sorry these aren't the best images, if needs be I can go grab a light to shine on them while I take the picture.

1st picture is the top buffer. Actually after looking at the uploaded pictures, those are horrid. Getting the good camera instead of my phone.


Edit: 2nd picture is top, 3rd bottom.

Edit2: I've run diode mode from ground and get closed connection on 4 of the screen connectors one one pin each. P4, P5, P6, and P7. From what I read that means those 4 ICs are shot, correct?

[tom66]

Re: LG 50PC3D-UD Screen problems

Test diode mode across the two large gold pads; if there's a short, then yes, the ICs are bad and you probably got bad parts.

[crbn79]

Re: LG 50PC3D-UD Screen problems

You are dead on, shows continuity of .024! 5 of the 6 ICs are showing shorts to ground as well. What are the chances that those would blow my replaced Y-Sus board?

[tom66]

Re: LG 50PC3D-UD Screen problems

They possibly have done damage to the Y-sus though due to your panel having a sustain output (glowing screen) you may have gotten away with it. So who sold you dud parts? The test is so easy to do, many sellers for some reason do not bother.

[crbn79]

Re: LG 50PC3D-UD Screen problems

Got it from an ebay seller who has sold a lot of parts with good reviews. I don't know if putting the name here breaks the TOS, so I'll avoid that unless I'm certain it does not. My Sustain board came from Coppel, but they were out of buffer boards or I would have ordered it at the same time from them.

[crbn79]

Re: LG 50PC3D-UD Screen problems

Thanks again for your help tom66!

[crbn79]

Re: LG 50PC3D-UD Screen problems

New buffer added. Now I have the following problem..... Does it ever end?? lol....

When the Input selection comes up on the screen it also gives a white box from top to bottom.

Bad Control Board? If so how do I go about testing this?