Black Vertical Bars Through 1/2 of Screen

[ckalugyer]

I have a LG Plasma 50" (50px4dr-UA) that started off with one solid intermittent black line through the screen that stops exactly half way down(Vertical). Eventually it stayed and became permanent. After about 3 months a 2nd one did the same thing and now a third one is starting to flicker one and off like the other 2 did almost a year to date that the first one started. It has served me well and has a brilliant & vibrant picture and cost me a pretty penny to buy new. Is there any information that I can give you to be able to fix this TV so i do not have to spend over $1200 on a new one of similar size/quality in today's market?

[drpj23]

Re: Black Vertical Bars Through 1/2 of Screen

I believe this is a hardware issue.
This may be a problem with X buffers on the bottom of the panel.
I think if you have horizontal lines it is a problem with the Y buffers/drivers so that's why I am assuming the X.
But first, re-seat your connectors. I'd focus on the ribbon cables connecting the buffers to the panel.
It could also be a solder connection prob on the ribbon cable from the X.

Just be very careful you do not rip one.

Hopefully it's just a ribbon problem, but if not, I would get a second opinion on the exact board to replace from someone on here. But, I am pretty sure it is a buffer board prob.
I have heard this could also be a failed panel, but I'm always skeptical of that answer sometimes lol.

[awyatt2]

Re: Black Vertical Bars Through 1/2 of Screen

looks like a buffer board, not sure on lg but toshiba has upper and lower buffer boards that can cause this, a bad ribbon connection,bad tab bonding among a few other things

[tom66]

Re: Black Vertical Bars Through 1/2 of Screen

It is an X-buffer problem; but on some LG plasmas, these parts are not replaceable (ICs are bonded straight to the panel...) Be careful operating it for a long time with those black bars you may have burn in on the screen.

[kc8adu]

Re: Black Vertical Bars Through 1/2 of Screen

often that is the resistors on the x ribbon cables.carefully resolder them.otherwise yes x buffer.

[ckalugyer]

Re: Black Vertical Bars Through 1/2 of Screen

I believe this is a hardware issue.
This may be a problem with X buffers on the bottom of the panel.
I think if you have horizontal lines it is a problem with the Y buffers/drivers so that's why I am assuming the X.
But first, re-seat your connectors. I'd focus on the ribbon cables connecting the buffers to the panel.
It could also be a solder connection prob on the ribbon cable from the X.

Just be very careful you do not rip one.

Hopefully it's just a ribbon problem, but if not, I would get a second opinion on the exact board to replace from someone on here. But, I am pretty sure it is a buffer board prob.
I have heard this could also be a failed panel, but I'm always skeptical of that answer sometimes lol.

Are there any specific connectors I should focus on on the X since they are in the mid-section of the screen? I usually repair laptops and PC's so I have some experiance with PCB's & connectors but nothing in the way of plasmas.

[ANDRASONI LUCIAN]

Re: Black Vertical Bars Through 1/2 of Screen

Bad ribbon connection, clean it and resold the smd resistors who is at the ribbon.

[ckalugyer]

Re: Black Vertical Bars Through 1/2 of Screen

Hopefully it's just a ribbon problem, but if not, I would get a second opinion on the exact board to replace from someone on here. But, I am pretty sure it is a buffer board prob.

Okay, so I check all of the connecting ribbons and clean them with an alcohol swab, but to no avail. Would anyone happen to know the exact buffer board I should replace given the height and width of the problem in my original pictures post? I have three boards across the top consisting of XC_top, XL_Top and XR_top. Also, I have a resistor labeled D2 & D3 that look a little "cooked" compared to the D1, D4 & D5 resistors in the same corresponding parts. They also look almost as though they line up with the two spots on the board where I have the lines at, though this may just be a coincidence.

Thanks again for all the help too guys, as a new member I greatly appreciate it,let alone the quick response times. I will be a regular on here and hopefully be able to help others out once I get a firm grip on the stuff I am repairing.

[tibimakai]

Re: Black Vertical Bars Through 1/2 of Screen

Un alt Clujean.
Sorry to be off topic, it's in Romanian.

[awyatt2]

Re: Black Vertical Bars Through 1/2 of Screen

have you tested the resistors value compared to what they should be? my hitachi was the board right at the black column. remember silver and gold are tolerence read color code from other end. list the color bands probally 3 ,and i will decipher the code.

[drpj23]

Re: Black Vertical Bars Through 1/2 of Screen

Get the numbers off the buffer boards. (they are usually on a white sticker).....but if the problem is lying in a soldering connection on the ribbon cable then the boards won't fix it but you said you had some resistors that looked a little cooked.
Can we get a high quality picture of that?

Usually resistors are labelled Rxxx; you might be looking at diodes.

[ckalugyer]

Re: Black Vertical Bars Through 1/2 of Screen

Usually resistors are labelled Rxxx; you might be looking at diodes.

You're Right Drpj, I was looking at diodes, good call. Below are the HD Pictures.

Diode 3 (D3) I think looks bad compared to the other:
(Again, It just happens to be one of the two right in front of one of the black vertical lines, and the other is in front of the other black line (coincidence?))


Diode 4 (D4) Looks like it is in good working condition to me:

[awyatt2]

Re: Black Vertical Bars Through 1/2 of Screen

shop jimmy has the buffer boards for this tv, not too expensive

[ckalugyer]

Re: Black Vertical Bars Through 1/2 of Screen

shop jimmy has the buffer boards for this tv, not too expensive

"Notice! Almost all plasma manufacturers highly recommend replacing the Y Main and Y buffer (or buffers) when replacing any one of the set. If a good Y-Main is connected to a faulty buffer, there is a high degree of likelihood that damage will occur to your new Y-Main, and the opposite often holds true if a bad main is connected to good buffers. Just a word of caution."

After reading this, is this true or a ploy to make you buy multiple items?
(They are out of stock on the XC_Top buffer I need >.>) I

http://www.shopjimmy.com/lg-akai-687...ffer-board.htm

Not to 2nd guess but rather to confirm...Anyone else able to say which board it may be? I believe it to be the XC_Top but again, I am a novice at best...

[drpj23]

Re: Black Vertical Bars Through 1/2 of Screen

Ya, the diode does look different, could have gotten hot.
Really, your going to either have to take it out of circuit to test it or know its behavior in the circuit to really know if its bad.

I suppose, unanimously with this thread, go ahead and replace the x buffer boards.

As awyatt2 said, go with shopjimmy or you could try your luck with eBay. ebay is usually cheaper but is less reliable in if you are getting a good board or not.

[drpj23]

Re: Black Vertical Bars Through 1/2 of Screen

The buffers we are talking about is the X (they are located near the soundbar or the bottom of the tv)
The y buffers are on the side next to the y sustain (looks like a mini power supply with a heatsink usually on it).
I don't believe that rule applies in this case (someone correct me if I'm wrong though).

And generally, I would take it case by case, but yes a single board in the "y" section can take the whole section down and is not rare by any means of that happening.

[awyatt2]

Re: Black Vertical Bars Through 1/2 of Screen

here you go two in stock.
http://allprotvparts.com/product.php?id_product=4826

[tom66]

Re: Black Vertical Bars Through 1/2 of Screen

Neither of those two boards are buffers, as such. They just route the signals to the right parts of the buffer ICs. The actual buffers and the resistors which fail are bonded to the panel. I doubt those boards actually fail that often. The X-buffer ICs can fail because they deal with 60V at multiple-amp pulses for the X-addressing (Y-addressing is under much greater strain.)

[cadiman]

Re: Black Vertical Bars Through 1/2 of Screen

If that is a picture of the top of the tv where they split the vertical bar half for the upper boards and half for the lower boards. (x)

You may just have an upper board failure. That will be the case if this is an older plasma panel.

When they split the boards up failed boards will give you a block box either center or left or right, upper or lower.

I have yet to see black vertical bars be anything but panel failure.

I think I had one plasma that had just a failed board.

For 20.00 it is worth a try.

[jzs005]

Re: Black Vertical Bars Through 1/2 of Screen

Hey Guys, same TV, same exact issue. The problem started intermittently about 6 months ago and has gotten progressively worse. I purchased an LG 50" 50PX4DR PLASMA TV CT BUFFER Board, P/N 6870QXC008A. I installed the board, cleaning all the connections, ribbon cables, etc. Same result, same lines. In fact the TV acted strange afterwards, it would not start up right away, volume control would stop working, unable to switch video modes. I put the original board back in and the TV functions normally again, it just continues to have the same black lines. Any other thoughts or suggestions? Possibly I recieved a defective board? Thanks!!!