Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of screen

[bcarl]

Hello all,

I was hoping to get some input as to what might be wrong with my plasma TV.

So a few days ago I turned the TV on immediately noticed that the top half of the screen was blank. I turned the TV off and back on, same thing - top half blank.

I unplugged the TV for a full 24 hours or so and tried it again. The screen was back to normal - full picture.

Last night I turned the TV on again and now the top half of the screen is flickering - (pro-dominantly blank screen with the top portion of the screen flickering in and out).

The red LED power light on the front of the TV doesn't flash at all. Its solid red.

Any ways if anyone has any ideas that would be great. Obviously I don't want to spend a bunch of $ on a 720p TV that is approaching 6 years old.

Thanks in advance.

Brad.

[tom66]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

My guess would be a loose connector or rarely a cold solder joint. You'll have to take the case of the TV off and we can tell you what to reseat.

[bcarl]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

My guess would be a loose connector or rarely a cold solder joint. You'll have to take the case of the TV off and we can tell you what to reseat.

Will do that.

How many pictures of the back will you need? Just one or will you need close ups in each corner of the unit?

If the problem is with the upper portion of the screen does that automatically mean that the possible connector issue is with the SU Board?

Thank you very much for your assistance!

[tom66]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

SU is where I would focus. This is one of the boards on the left-hand side, when looking from the back of the set. Pictures of that and of the overall layout would be useful.

[bcarl]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

Bump for pictures update.

Thanks again for any assistance.

Couple questions. Do I have to leave the TV unplugged for any time frame before touching those ribbon cables in side? Also if I adjust the cables, can I turn the TV on without the back cover on?

Brad.

[tom66]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

I would get an insulated screwdriver and press down (insulated end) on the lefthand white connector which goes from the SC to the SU board.
https://www.badcaps.net/forum/attach...2&d=1363316484

The ribbons themselves are probably OK.

[bcarl]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

I would get an insulated screwdriver and press down (insulated end) on the lefthand white connector which goes from the SC to the SU board.
https://www.badcaps.net/forum/attach...2&d=1363316484

The ribbons themselves are probably OK.

Tried pushing down on the white connector with an insulated screw driver (insulated end as you mentioned).

Problem still persists.

Would it be worth while re-connecting the ribbons or do those normally stay in place pretty good?

[tom66]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

Well, one missing ribbon would cause just one part that it controls to go out.
Try unplugging the connector and plugging it in again (do this with power off.)
Also try looking at the right hand side: the Z-electrode, which connects to the SS board.

[bcarl]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

Thanks for the reply.

I undid the white connector and did it back up. Problem still persists.

I am not sure what the Z-electrode is, but I checked all wires running into the SS board and they're all connected in there tight - checked it again and the problem is still there.

[tom66]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

The Z-electrodes (or Y2-electode) are the ones on the right of the panel.

[bcarl]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

Sorry Tom,

I still have no clue part you're referring to. Sorry

I called the local Panasonic service depot here and they were pretty confident that the SU Board was the source of all the problems...

Thing is I would hate to order the part just to find out that wasn't the root cause of my issues with the TV...

Thanks,

Brad.

[tom66]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

On the right hand side of the TV you have some brown plastic strips disappearing behind the metal plate. Behind that is the actual plasma panel. Those are the Z electrodes.

Please try this:
- Hold VOL- on the TV
- Press "0" three times on the remote while holding VOL-
- Release VOL-
- Wait approximately 10 seconds. The display may flicker and change size/brightness, this is normal.
- When the service menu appears, press red three times on the remote.
- Press red to move forward through the test patterns, green to go back.
- Are the test patterns affected by the glitch?

[bcarl]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

On the right hand side of the TV you have some brown plastic strips disappearing behind the metal plate. Behind that is the actual plasma panel. Those are the Z electrodes.

Please try this:
- Hold VOL- on the TV
- Press "0" three times on the remote while holding VOL-
- Release VOL-
- Wait approximately 10 seconds. The display may flicker and change size/brightness, this is normal.
- When the service menu appears, press red three times on the remote.
- Press red to move forward through the test patterns, green to go back.
- Are the test patterns affected by the glitch?

Ok, found the Z electrodes. They seem to be fine.

I wasn't able to enter using the method provided, but was able to enter by using the recall button method.

From there I brought up all the test patterns where the screen changes colour, size, diagonal lines, etc... The screen is still affected by this glitch. The display in this mode seemed to be a little better than having the TV on normally, but none the less, its still being affected by the glitch.

Thank you very much for you help thus far!

[bcarl]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

Hello its me again.

I have an update on my TV...

I attempted the road of least resistance (cheapest too) and replaced the SU Board (purchased it from ebay).

Upon installing the SU board, I got a 7 LED light blink code and the display screen wouldn't fire up.

I then installed the original SU Board back into the TV... Works the same as mentioned in this thread. TV fires up, upper half flickers, lower half is normal. No right LED flashing.

Either I got a defective SU Board off of ebay or there's something else wrong with the TV set and I blew a few bucks on an SU board.

FWIW, I tried the 7 LED blink diagnostic test (from the Technical Guide PDF). I disconnected the SC2 and SC20 connectors (did it twice with both SU Boards) and tried to turn on the TV both times the display did not fire up. This is where I ended my diagnostic tests. Measuring 15Vdc is beyond my capabilities - also don't have a voltage meter.

Also for kicks, I completely removed the SU Board from the TV and turned? it on (hooked SC2 and SC20 connectors back up). The TV display fire up normal on the bottom. The top was completely black.

Do you have any suggestions? Or is it new TV time? Is there a chance I just got a defective SU Board off of ebay?

Thank you so much for your help.

Brad.

[tom66]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

The replacement SU is defective. I (and others) are encountering so many defective SU boards on eBay etc that I always aim to get them from places like ShopJimmy, flattvparts as those usually come from transit damaged TVs.

The SU boards become defective because the cracked plasma panel damages them when power is applied to the TV. (They are harvested from cracked screen TVs.) Most of the boards on eBay are from victims of wii controllers that were on as they were being hit.

[bcarl]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

The replacement SU is defective. I (and others) are encountering so many defective SU boards on eBay etc that I always aim to get them from places like ShopJimmy, flattvparts as those usually come from transit damaged TVs.

The SU boards become defective because the cracked plasma panel damages them when power is applied to the TV. (They are harvested from cracked screen TVs.) Most of the boards on eBay are from victims of wii controllers that were on as they were being hit.

Thanks. I will start the process in returning the SU Board.

Any advice on what I should do at this point? I could possibly borrow an SU Board from an exact model TV to mine. My only issue is if the problem doesn't lie in the SU Board on my TV, would any damage be caused to the SU Board I borrowed from the donor TV? IE I wouldn't want to damage the SU Board I borrow and be in a situation where I am buying two TV's.

Thoughts?

EDIT - Not sure if its worth noting, but I was searching the forum and saw a post of yours asking if another member ever had the infamous panasonic buzz in their TV set. I have had had this annoying buzz in the past it seemed that it would intensify depending on the dark to bright colour changes in the screen. I adjusted my brightness settings to reduce the buzzing sound that came from the TV. Would this buzz have anything to do with what may be wrong with my TV?

Thanks so much again.

[tom66]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

Any advice on what I should do at this point? I could possibly borrow an SU Board from an exact model TV to mine. My only issue is if the problem doesn't lie in the SU Board on my TV, would any damage be caused to the SU Board I borrowed from the donor TV? IE I wouldn't want to damage the SU Board I borrow and be in a situation where I am buying two TV's.

I would doubt damage would be dealt, but I wouldn't harvest parts from a working TV myself. There is a rare chance the plasma panel itself is defective which has damaged the SU board. I say rare, because I only know of this problem on certain models of the 42" PZ70 series, which is quite different from your model.

EDIT - Not sure if its worth noting, but I was searching the forum and saw a post of yours asking if another member ever had the infamous panasonic buzz in their TV set. I have had had this annoying buzz in the past it seemed that it would intensify depending on the dark to bright colour changes in the screen. I adjusted my brightness settings to reduce the buzzing sound that came from the TV. Would this buzz have anything to do with what may be wrong with my TV?

The infamous buzzing is due to loose screws on the case of the TV and on the SC and SS boards. When you fix the problem undo all of the screws on the SC, rub them down with a scouring pad and re-install them. Then tighten the case screws securely. When I was working on my Panny plasma, I found it would buzz horribly when I only had two screws installed. The operation did not adversely appear affected.

[bcarl]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

I would doubt damage would be dealt, but I wouldn't harvest parts from a working TV myself. There is a rare chance the plasma panel itself is defective which has damaged the SU board. I say rare, because I only know of this problem on certain models of the 42" PZ70 series, which is quite different from your model.



The infamous buzzing is due to loose screws on the case of the TV and on the SC and SS boards. When you fix the problem undo all of the screws on the SC, rub them down with a scouring pad and re-install them. Then tighten the case screws securely. When I was working on my Panny plasma, I found it would buzz horribly when I only had two screws installed. The operation did not adversely appear affected.

Thanks for the input.

Would my next course of action be to track down an SU Board from the vendors you previously mentioned? Shopjimmy and flattvparts I think flattvparts had one in stock.

[tom66]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

Yes, I would prefer ShopJimmy myself though.

[bcarl]

Re: Display issue with 50" Panasonic Plasma TH-50PX75U - issues with top half of scre

Hello Tom,

Quick update here. I received the SU Board I ordered from FlatTVParts (shopjimmy didn't have any in stock). Anyways I just put the SU Board in and BOOM, full TV screen with no flickering.

Thank you so much for your assistance - its really appreciated.

Brad.