Help! with Panasonic plasma TX-P42GT30B half dead screen, display driver?

[danatoakhill]

Hi all,

Can anyone help me out? I'm about to start work on a P42GT30B plasma screen which seems to have half the screen dead except for some vertical white lines and a series of odd shaped white marks. (see image).

If it was only one strip that was dead I'd assume it was a fault in the screen driver ribbon cable, but as a whole half of the screen is affected is it possible that it's one of the driver boards rather than the screen (and therefore possible to repair / replace?)

Not sure about the odd shaped marks...I'm pretty certain that the screen isn't cracked or impact damaged...but not sure what could cause that shape.

Any advice would be appreciated...I normally repair LCD screens as projects, but thought I'd give a plasma a go!

Cheers,

Dan

[tom66]

Re: Help! with Panasonic plasma TX-P42GT30B half dead screen, display driver?

That could be a faulty plasma panel. Do the spots go away if the column drivers for that side are unplugged?

[danatoakhill]

Re: Help! with Panasonic plasma TX-P42GT30B half dead screen, display driver?

Cheers for that, that would be my first step...to unplug the column drivers and see if I get any change in the spots or lines.

Unfortunately, I haven't actually bought the TV yet...an acquaintance is selling it for pretty cheap (£60), but I'm trying to weigh up whether I could fix it for myself, or at least make it somewhat better to sell on. So I only have the picture to go on.

My first though was that the plasma panel was faulty as you see that quite a lot, but for what I've seen you more often see just one column blacked out or with lines on, and that points to a fault with the panel, or at least the attached ribbon cable.

But as half the screen is affected, and I'm guessing that there are 8 channels on the column driver board, with two strips per channel...that means that four of the 8 ribbon cables would have to be faulty to cause half of the screen to be dead.

Would it be more likely that there's a problem with the driver board...or even if there are two driver boards (one for each side with 4 channels on each), that one of the boards has failed?

I know these questions can't really be answered until I get the unit, but as I said, I'm trying to weigh up whether I can replace the board...or whether I'll be left with a huge, still half dead, tv and whether it's worth the effort and money involved in going to pick it up!

Thanks for you help and any other comments!

Dan

[tom66]

Re: Help! with Panasonic plasma TX-P42GT30B half dead screen, display driver?

Cheers for that, that would be my first step...to unplug the column drivers and see if I get any change in the spots or lines.

Unfortunately, I haven't actually bought the TV yet...an acquaintance is selling it for pretty cheap (£60), but I'm trying to weigh up whether I could fix it for myself, or at least make it somewhat better to sell on. So I only have the picture to go on.

My first though was that the plasma panel was faulty as you see that quite a lot, but for what I've seen you more often see just one column blacked out or with lines on, and that points to a fault with the panel, or at least the attached ribbon cable.

But as half the screen is affected, and I'm guessing that there are 8 channels on the column driver board, with two strips per channel...that means that four of the 8 ribbon cables would have to be faulty to cause half of the screen to be dead.

Would it be more likely that there's a problem with the driver board...or even if there are two driver boards (one for each side with 4 channels on each), that one of the boards has failed?

I know these questions can't really be answered until I get the unit, but as I said, I'm trying to weigh up whether I can replace the board...or whether I'll be left with a huge, still half dead, tv and whether it's worth the effort and money involved in going to pick it up!

Thanks for you help and any other comments!

Dan

I'm going to place my 10p on the driver board. Each of the columns has a little chip embedded onto the flex on the plasma panel. This chip can go bad, causing the column to go black, but if half the screen has gone bad, then it's most likely something common to that. If the manual says the screen has two halves, then it might be easy, just replace one half. On one 42" Panasonic Plasma I worked on, it had three horizontal drivers, so that kind of fault could not have occurred.

The boards inside the Panasonic plasmas are worth a lot anyway, so it might be good for stripping for parts if it isn't easy to fix.

[danatoakhill]

Re: Help! with Panasonic plasma TX-P42GT30B half dead screen, display driver?

That's a very good point! It's been a while since I last worked on an TV, but I have sold off the parts before and would most likely make the money back just doing that!

The service manual does show two data driver boards (C1 and C2) and what do you know...C1 (the affected one) is being sold on a parts website for £19...so I think the project is a go!

Thanks for the advice,

Dan