Panasonic TC-P50ST50 5" vertical black bar

[stupidPanny]

My TV likes to intermittently flash this vertical line
.

I read the troubleshooting guide from here, and my best guess is the "Vertical Line-Same width as FPC" even though the blacked out area is larger than what they say it should be.

I took off the back, wiggled around the cables and reclamped them which seemed to make the problem better. Prior, the black bar would show 20%-30% of the time, after my calibrated wiggle they disappeared for a couple weeks. Now, they are back at 70%.

Any suggestions on what to try next?

[tom66]

Re: Panasonic TC-P50ST50 5" vertical black bar

Just out of warranty I guess? Newish set.
I'd check all connectors along the C board, and check ribbon cable is fully seated.

[stupidPanny]

Re: Panasonic TC-P50ST50 5" vertical black bar

Tom66, thanks for the reply. Unfortunately the warranty on these is only 1 year, so I'm well out by now.



By ribbons, I assume you mean those that appear to wrap around to the front, on the left side of this picture?

Which connectors should I be looking at?

[tom66]

Re: Panasonic TC-P50ST50 5" vertical black bar

Along the bottom left side of the "A" board (which has all the video inputs on it like HDMI) there are two fat ribbons and one smaller one. I'd see that both fat ones are seated correctly on both ends. Only make changes to these with power to the set disconnected from the wall.

[stupidPanny]

Re: Panasonic TC-P50ST50 5" vertical black bar

Would you suggest that I just adjust those ribbons to start with? Also, how dangerous is it to turn the TV back on without replacing the back casing?

[tom66]

Re: Panasonic TC-P50ST50 5" vertical black bar

Yes, those ribbons would be my first check point.

You can operate the TV without the case on, just do not touch any part as it could present an electrocution hazard. Plasma display use 200 volts for panel sustain and 350 volts for panel initialise, so that presents a shock hazard...

[stupidPanny]

Re: Panasonic TC-P50ST50 5" vertical black bar

Tried it, and unfortunately a no-go. What's the next idea?

[tom66]

Re: Panasonic TC-P50ST50 5" vertical black bar

Try tapping lightly around the connectors on the C board or A board with an insulated screwdriver handle - any difference to the picture?

[stupidPanny]

Re: Panasonic TC-P50ST50 5" vertical black bar

Nothing, but I can't easily get to the connectors on the bottom from the C1/2/3 buffer boards as they wrap around into the screen.

Noticed that the 3 buffer boards have 15 ribbons, which if spaced equally on the screen they would each cover ~2.9". Since the black bar is roughly 9", that might mean 3 consecutive areas are not displaying correctly. Add in that the area that is not showing is ~14.25" from the edge, if everything aligns it would mean the rightmost 3 ribbons from C2 are aligned with the problem area.

[tom66]

Re: Panasonic TC-P50ST50 5" vertical black bar

Yes, you can try reseating those now. However, I suspect that your problem is with either the C(1,2,3) board or A board. Not sure which.

[tw2005]

Re: Panasonic TC-P50ST50 5" vertical black bar

Yes, you can try reseating those now. However, I suspect that your problem is with either the C(1,2,3) board or A board. Not sure which.

Give the mirror option a go in service mode

"6.2. Option - Mirror
Picture can be reversed left and right or up and down.
00 : Default (Normal picture is displayed)
01 : Picture is reversed left and right.
02 : Picture is reversed up and down.

If the defective symptom (e.g. Vertical bar or Horizontal bar) is moved by selection of this mirror, the possible cause is in
A-board"

[tom66]

Re: Panasonic TC-P50ST50 5" vertical black bar

Good idea. Didn't think of that.

[tw2005]

Re: Panasonic TC-P50ST50 5" vertical black bar

Almost worth a gamble at $30 for a full set of C buffers.

PM sent with links.

Has all parts for yours it appears and seriously cheap!

Hope it's not the panel. If me I'd grab a full set of spares looking at these prices if the panel ends up good. About $220 for a full suite.

Worst case if the panel is shot sell the parts or park it and hope another 50ST50 surfaces with a good panel and blown SC,A etc for sale.

[stupidPanny]

Re: Panasonic TC-P50ST50 5" vertical black bar

Okay, made it into the service mode but how do I get a picture to display? It won't let me save the reversed setting, and the background is black so I can't tell if there is a "black bar"

[tom66]

Re: Panasonic TC-P50ST50 5" vertical black bar

It should be on whatever input last. You can turn it off first, set an input up (e.g. HDMI or onboard tuner) then turn it on again with that input still connected, it will boot up into service mode like that. At least, that is how it has worked on the older sets, I do not think they have changed it.

[stupidPanny]

Re: Panasonic TC-P50ST50 5" vertical black bar

Ah, that worked. I think the only input it doesn't work for is USB, which is what I was using.

The black bar remained in place, so I have to assume this is likely the C boards?

Also, does the fact that it is only flashes up indicate something else? The flashing is tempermental. It seems to be rare when the TV starts up, then get progressively worse for a few hours. If you let the TV on for 12+ hours, it becomes more rare.

[tom66]

Re: Panasonic TC-P50ST50 5" vertical black bar

One thing you could try doing is getting a hairdryer out and start heating up parts. As the set warms up something is expanding and losing contact, or otherwise failing to work, and heat will make this happen quicker. Just be sure not to get it too hot, about 30 seconds in an area should be enough to narrow down a particular part.

The fact that the bar doesn't move doesn't rule out all possible A board faults. If it did move, it would be a certain A board fault.

[stupidPanny]

Re: Panasonic TC-P50ST50 5" vertical black bar

Alright, finally had a chance to try this out and wasn't able to really achieve much. The bar is fairly hard to predict, so i couldn't really tell when I was accomplishing anything.

Any other suggestions, or is it worth replacing both A and C boards at this point?

[Frank3y3]

Re: Panasonic TC-P50ST50 5" vertical black bar

God Damn, i'm a begin to suspect Tom and Tw works as FBI Panasonic technicians. These guys are very helpful at giving inputs where to go, what to inspect and what to try. Thumbs up !

[tom66]

Re: Panasonic TC-P50ST50 5" vertical black bar

Little does anyone know, I'm actually working for Panasonic trying to stop people buying Samsung and LG panels as replacements .