LG 50" Plasma 50PQ30-UA, Half Screen is Black


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LG 50" Plasma 50PQ30-UA, Half Screen is Black

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hessand
New User

Jul 8, 2012, 11:23 PM

Post #1 of 7 (12475 views)
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LG 50" Plasma 50PQ30-UA, Half Screen is Black	Can't Post

Hi guys, I have a quick question on my TV. When I turn on this set, the bottom half remains black, while the top half turns on. However, after about a second of that, the whole set turns off.
From what information I could find, this seems to indicate that the lower Y Buffer Board could be faulty.
I just wanted to check if you all concur with this, and think that replacing the Lower Y Board could fix this issue?

Thanks in advance!

74f100
Enthusiast

Jul 9, 2012, 12:12 AM

Post #2 of 7 (12463 views)
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Re: [hessand] LG 50" Plasma 50PQ30-UA, Half Screen is Black [In reply to]	Can't Post

That sound correct. One thing to check before ordering, make sure all the connectors are seated properly. Re-seat them all, including the panel to Y-buffer connectors.

Good luck,
Jim
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hessand
New User

Jul 14, 2012, 12:47 AM

Post #3 of 7 (12424 views)
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Re: [74f100] LG 50" Plasma 50PQ30-UA, Half Screen is Black [In reply to]	Can't Post

Thanks for the help, but of course, new problems always arise! I replaced the lower Y board, which solved the problem of the lower half not displaying. However, now what I see is the left third of the TV or so does not display. You can see an example at this link.
http://i.imgur.com/ajEQj.jpg
The white blotch is the message saying "No Signal" that's getting cut off by the screen issue.
Any thoughts?

Thanks,
Andrew

(This post was edited by hessand on Jul 14, 2012, 12:47 AM)

74f100
Enthusiast

Jul 14, 2012, 3:25 PM

Post #4 of 7 (12412 views)
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Re: [hessand] LG 50" Plasma 50PQ30-UA, Half Screen is Black [In reply to]	Can't Post

Check the ribbon cables again.

A left to right cut off is from the Y-buffers. Up and down are the logic buffers. IIRC that set only has the one on the bottom. There is also a cable that goes from the Y-Sustain to the logic buffer.

What you had before, and what you have now don't really correspond. When that happens, I always stop, and go back over any and everything I've done with the TV.
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hessand
New User

Jul 15, 2012, 4:00 AM

Post #5 of 7 (12399 views)
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Re: [74f100] LG 50" Plasma 50PQ30-UA, Half Screen is Black [In reply to]	Can't Post

After checking and rechecking the connections on the Y-buffers, there was only one apparent issue. Soldered to a connector on the Upper Y Board is a wire that proceeds to then loop around a small screw on the Y Sustain board. However, the other end of this wire is not soldered elsewhere. A poor picture representation of this is at the link here (my normal camera is broken).
http://i.imgur.com/6vNDf.png
I have no clue where this wire is supposed to go, as it was apparently never soldered (to my knowledge), is not on diagrams, but was still taped down in a very purposeful looking way.
Any clue?

Thanks,
Andrew

jts1957
Veteran

Jul 15, 2012, 10:09 AM

Post #6 of 7 (12394 views)
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Re: [hessand] LG 50" Plasma 50PQ30-UA, Half Screen is Black [In reply to]	Can't Post

Could it be a 'wire tie?'

-------------------------
Location: Far, Far Away

74f100
Enthusiast

Jul 15, 2012, 6:14 PM

Post #7 of 7 (12385 views)
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Re: [hessand] LG 50" Plasma 50PQ30-UA, Half Screen is Black [In reply to]	Can't Post

I don't recall any individual wires or holders on that model.

You do have the ribbon cable connecting the upper and lower buffers in....IIRC if that set is run without that AND connected to the panel it will blow the Y-sustain.

Jim
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