LG 50PA650T vertical bars.

[Dang]

Just got this one in and it has an issue with some white repeating vertical bars, it's the same pattern over the screen, I have taken the back off and nothing seems out of the ordinary, but what I do see is a constant red light on the main connections board and a green light on the logic board that flashes a repeating long green directly followed by a short green, something like this:

___ _ ....... ___ _ ....... ___ _ etc etc.

I hope that shows it OK.

Anyway, I was hoping someone might know what this means, if anything, and what might be causing the vertical white pattern? thanks.

[tom66]

Re: LG 50PA650T vertical bars.

Try engaging the test pattern jumpe on the control board, EXT AUTO GEN. LVDS cable should be unplugged and points shorted together.

After you repair the set, please remove two plastic stand off on the side of the panel as it can eat into the ribbons on the panel, killing it. In this picture, the black objects near the ribbons. Seen a lot on these forums with this fault:
https://www.badcaps.net/forum/attach...1&d=1417209330

[Dang]

Re: LG 50PA650T vertical bars.

Try engaging the test pattern jumper on the control board, EXT AUTO GEN. LVDS cable should be unplugged and points shorted together.

After you repair the set, please remove two plastic stand off on the side of the panel as it can eat into the ribbons on the panel, killing it. In this picture, the black objects near the ribbons. Seen a lot on these forums with this fault:
https://www.badcaps.net/forum/attach...1&d=1417209330

Cheers for the response Tom, can I ask where this EXT AUTO GEN jumper is and which cable is the LVDS cable? I'm presuming the one from the main connection board to the logic board, also, could you please clarify where exactly these black plastic bits are and how best to remove them? thanks again, Andy.

[tom66]

Re: LG 50PA650T vertical bars.

Bottom right of this board:
https://www.badcaps.net/forum/attach...0&d=1417209330

EXT_AUTO_GEN is in a highlighted box. Two holes must be jointed and LVDS cable must be disconnected.

[Dang]

Re: LG 50PA650T vertical bars.

Thanks Tom, this I will do at some point tomorrow, going back to these plastic bits by the ribbon cables, I can't really see where they are so can I ask how best to remove them?

I have read a past post of yours on this particular Tv and knew this was still good, probably a logic or main board issue but for sure this ribbon cable issue is worrying and seems prevalent among these Tvs so catching it now is important.

[tom66]

Re: LG 50PA650T vertical bars.

To avoid confusion see image. I can already see it slightly protruding so it's only a matter of time. (I think it's related to the thin frame flexing under temperature, or possibly as the set is moved or bumped.)

[Dang]

Re: LG 50PA650T vertical bars.

Hi Tom, I've done the pattern test and it's still the same except for some slight variances as each test pattern is displayed. So we know it's not originating from the main connection board, the fact that we get a nice bright picture would suggest the Y-sus and X-sus are OK along with the buffer boards, so that leaves the Z-sus boards and control board, I would of thought considering the pattern repeats across the screen as it does the Z-sus boards are OK too, that just leaves the control board, what are your thoughts? thanks again, Andy.

I have had a look at the piece of plastic in question and have found it to be covered with a felt like material, this runs the whole length of the ribbon cable area, is this what you have found too?

[tom66]

Re: LG 50PA650T vertical bars.

It looks like a control board fault to me. Test patterns eliminate the main board as a cause.

Under the felt there's a small plastic/metal indent which pushes its way into the ribbons, this is what causes the fault.

[Dang]

Re: LG 50PA650T vertical bars.

Thanks Tom, it's the cheapest option so fingers crossed. This tab, what's the best(safest) way to remove it?

[tom66]

Re: LG 50PA650T vertical bars.

Well, I haven't tried one yet. But I'd suggest taking the facia off carefully then grinding it down with a dremel or similar tool.

There's one on the bottom which might be worth doing too. Just in case. Not seen that one kill the panel yet though.

[Dang]

Re: LG 50PA650T vertical bars.

Do you think something could be put over it to blunt it? I've had the frame off at the top, a single screw holds it, the front glass is set within it but it does create just enough space to get a sharp blade in, I might carefully try that, filing it down might create a lot of work afterwards cleaning it all away, thanks, Andy.

[tom66]

Re: LG 50PA650T vertical bars.

There is already something over it, from memory on mine it had worn down. Think it was a bit of foam. Can't remember for sure though. The glass can be removed and put aside carefully.

[freakaftr8]

Re: LG 50PA650T vertical bars.

The object over the plastic trim piece is a black piece of cloth tape not very good and easily penetratable. Bad design. I would just pull the plastic bezel back away from the screen and grind those tabs off completely. The fact that when the panel heats and contracts constantly that cable rubs against that black piece of plastic pushing on the cable eventually cracking through.

Tom is right both him and I have both encountered this problem. a very easy way to destroy a perfectly good panel

[Dang]

Re: LG 50PA650T vertical bars.

So the logic/control board cured the issue and the Tv is now working perfectly. As for the tab, I simply adjusted the frame moving it over slightly which has given about 2mm extra clearance so should be OK, I did look at the ribbon cable to see if there was any evidence of this "rubbing" and saw none so maybe it's just a few of these sets that suffer from it.

I do have another issue with the Tv, Freeview HD goes blank momentarily whist watching most of the HD channels, from what I've read it's a known issue but I've seen no cure, has anyone any ideas on what might cause this? thanks again, Andy.