Panasonic TH-42PZ80U Plasma Red Screen Issues

[consult20]

Thanks in advance for any insight as to what may be the problem with this TV.

When the TV is first powered on, it works fine. Then after some time (may vary from 1/2 hour to several hours), the pictures gets very red -- almost looks like a red mosaic picture. I took some pictures of the red screen issues and have included links to the pics. Does this look like a problem with the Y-SUS or X-SUS board?

Thanks again for your help.

[tom66]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

It looks more like a control board problem, it's not likely to be a Y-sus/X-sus (Panasonic: SC/SS) problem.

Does the red colour affect the OSD (user interface, like volume control)?

[consult20]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

Tom,

I just turned on the TV and will check to see how it affects the user interfaces like volume, menu, etc., and will post additional pics (it will take some time for the TV to go into "red screen" mode).

When I was taking pictures originally of this problem, another symptom is that when I change channels the screen goes completely solid red until the next channel tunes in (about 1 second or less). Attached is a picture I previously snapped quickly while changing channels.

Thanks for your help.

[consult20]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

Tom,

Ok the TV just went into "red screen" mode, and yes the user controls are also affected by the red screen mosaic symptoms. See attached pics for examples. Thanks again.

[tom66]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

I'm going to say it's likely to be a control board problem. Unfortunately, on most Panasonic plasmas, this is buried right under the main board, so you have to remove that first to get to it. Since the problem gets worse when it warms up, it could be as simple as a loose connector between the control board and main board - this has been observed with some LCDs.

It looks like black has been replaced with red, or red is for some reason almost always on.

[consult20]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

Tom,

Yes this seems like a really a strange phenomenon, hard to explain so pictures were a must.

Is the control board also known as the main logic board?

Thanks again for your help.

[tom66]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

Tom,

Yes this seems like a really a strange phenomenon, hard to explain so pictures were a must.

Is the control board also known as the main logic board?

Thanks again for your help.

I've seen something similar on an LG plasma (branded as Thomson Wysius); in that case the green was affected, but it wasn't flood-filled like on your set, just banded slightly, on some scenes it was very obvious. I found out that bit #3 of the green channel was always zero. Never managed to fix it, sold as faulty, but it was only an old 480p set, so not really worth much anyway.

The control board could be called the main logic board. Don't confuse it with the main board, which is the board that has all of the inputs on it.

[Toasty]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

Since it seems directly heat related... Are the fans clean and all running?


A photo would help locate the boards easier.

[consult20]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

Yes the fans are all clean and work fine, the TV inside is very clean, almost no dust at all.

It does seem heat related since it only happens after the TV has been running awhile. But I'll make sure all connections are clean and secure first, and then will see if it happens again.

And I'll post some pics on Monday of the inside back of the TV, thanks again for the input and suggestions.

[consult20]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

I attached pics of the back of the tv, and a pic from the service manual identifying each board.

The problem is definitely heat related -- I put a small fan behind the tv blowing directly on the A board, and it ran fine for over an hour. Then I turned off the fan and the "red screen" issue showed up within 5 minutes.

I'm not sure how to proceed at this point, I'd appreciate any more advice on this.

[selldoor]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

Hi I once had a small lcd tv that turned green when warm - never did find the problem but "cured" it by bending the main board and eventually packing it in the bent position.
Probably a cold joint or processor lifting but couldnt pin it down.
So you could try pressing gently but firmly on different parts of the board to see if you can either get it to turn red when cold or make the red go off when hot. I used a wooden dowel. I dont know anything about Plazma but on lcds there is a cable LVDS takes the video signal to the panel and reseating this helped with some screen problems.

[consult20]

Re: FIXED!! Panasonic TH-42PZ80U Plasma Red Screen Issues

Tom,

You were spot on with the problem, it was a connector on the main logic board that had come loose. I had to remove the A board and bracket in order to get to the D board (logic board). I noticed immediately one of the connectors wasn't fully seated, so I simply plugged it back in securely and re-assembled the A board with a couple screws, and it's been working fine for over an hour. It had gotten to the point where it would go "red screen" within 5 minutes, so I'm very confident that it's now fixed.

Thanks for your help, and everyone else's suggestions as well!

It's too bad Panasonic didn't use connectors with the small clips to hold these in place better -- they use them on some of the connectors but not all.

Thanks again, I'll post an update tomorrow after it's been on for several more hours, just to confirm this was the problem.

[consult20]

Re: FIXED!! Panasonic TH-42PZ80U Plasma Red Screen Issues

I'm going to say it's likely to be a control board problem. Unfortunately, on most Panasonic plasmas, this is buried right under the main board, so you have to remove that first to get to it. Since the problem gets worse when it warms up, it could be as simple as a loose connector between the control board and main board - this has been observed with some LCDs.

It looks like black has been replaced with red, or red is for some reason almost always on.

Tom,

The plasma is definitely working flawlessly again thanks to your excellent analysis of the problem. I ran it for several hours yesterday, and a couple hours this morning without incident.

And you were right about the location of the logic board, it was behind the A board fastened to a bracket with 8 screws. The bracket itself was held in place with 4 screws. And there were 10 connectors I had to unplug from the A board in order to get it out of the way.

Thank you again for your help diagnosing the problem with this plasma, I'm really amazed that a loose connector was the culprit since it worked fine when first turned on and then would go "red screen" after it warmed up.

[tom66]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

I'm glad you fixed it ! Enjoy your TV.

On an LG Plasma I have, the video data connector has some very strong tape holding it down. Not that I would recommend LG by a long stretch.

[consult20]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

I'm glad you fixed it ! Enjoy your TV.

On an LG Plasma I have, the video data connector has some very strong tape holding it down. Not that I would recommend LG by a long stretch.

If this ever happens again, I'll use tape on that connector as well -- good idea. I have no experience with LG at all, but yes it seems a lot of people don't think highly of their tv's. I've fixed LCD's from Polaroid, Vizio, and Samsung, and plasmas from Panasonic and Samsung. Had a 42" Sanyo plasma that wasn't worth fixing since the buffers and Y-main all went out. Too bad the manufacturers can't come up with a way to prevent the buffers from taking out the Y-main, seems like it shouldn't be that difficult to do.

[tom66]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

If this ever happens again, I'll use tape on that connector as well -- good idea. I have no experience with LG at all, but yes it seems a lot of people don't think highly of their tv's. I've fixed LCD's from Polaroid, Vizio, and Samsung, and plasmas from Panasonic and Samsung.

Of all TV manufacturers, LG is okay. But they continue to use crap capacitors, which have poor lifespans. Such as Samwha. I pulled 9 of them from a plasma and 4 from an LCD both by LG. And they continue to use hybrids, to reduce the cost of manufacturing the TV, but this comes at the expense of a single module that must be changed instead of individual components. If they didn't use such crap caps and stopped using hybrids in their plasmas... I might actually recommend them. The design and engineering is otherwise very good.

Had a 42" Sanyo plasma that wasn't worth fixing since the buffers and Y-main all went out. Too bad the manufacturers can't come up with a way to prevent the buffers from taking out the Y-main, seems like it shouldn't be that difficult to do.

Well, you say that, but I know of only certain Samsung PDPs that are affected by that. Had an LG plasma where the buffer went up in smoke but the Y-sustain still worked. Same for a Panasonic plasma. I've dealt with all three plasma manufacturers (LG, Samsung and Panasonic) and of them the order of preference would be Panasonic, LG and Samsung. I opened one 42" Panasonic and it was awesomely over-engineered; the newer Samsung designs seem to be experimenting with removing as much components as possible and still selling them at ridiculous prices... I'm guessing even if they manage to produce one of their series 4 plasmas at below LCD cost, they would never sell it at a lower price because it might kill their LCD market.

[consult20]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

Of all TV manufacturers, LG is okay. But they continue to use crap capacitors, which have poor lifespans. Such as Samwha. I pulled 9 of them from a plasma and 4 from an LCD both by LG. And they continue to use hybrids, to reduce the cost of manufacturing the TV, but this comes at the expense of a single module that must be changed instead of individual components. If they didn't use such crap caps and stopped using hybrids in their plasmas... I might actually recommend them. The design and engineering is otherwise very good.



Well, you say that, but I know of only certain Samsung PDPs that are affected by that. Had an LG plasma where the buffer went up in smoke but the Y-sustain still worked. Same for a Panasonic plasma. I've dealt with all three plasma manufacturers (LG, Samsung and Panasonic) and of them the order of preference would be Panasonic, LG and Samsung. I opened one 42" Panasonic and it was awesomely over-engineered; the newer Samsung designs seem to be experimenting with removing as much components as possible and still selling them at ridiculous prices... I'm guessing even if they manage to produce one of their series 4 plasmas at below LCD cost, they would never sell it at a lower price because it might kill their LCD market.

The Panasonic is impressive, and the picture is outstanding -- and it's still working flawlessly so I put it all back together now.

I know what you mean about cheap caps, a real weak point on a a lot of LCDs and plasmas it seems. At least they're cheap and easy to replace, even buying the best quality available.

Thanks again Tom, you really know your stuff!

[snowmaker77]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

My 50" Pan. plasma had this "red pixel" issue, intermittent at first then all the time. I found this forum and thread via a Google search and want to thank you all for taking the time to help us out.
I did not notice any loose connectors, but I did pull and re-seat the few going to this "D Board" and the TV now seems to work fine (been running just a few minutes) but before I dug into it, it had the red screen issue for the past 4 days. I will run it for the day before putting it back together, but REALLY, you guys saved me!
I didn't dare probe / touch / wiggle ANYTHING while the unit is plugged in or powered up, so I don't know exactly which connector(s) were the problem.

Is there any more direction any of you could provide in case this happens again? It wouldn't be a surprise me a bit if it does it again someday.
It was a little dusty in there (bought new 3 ys. ago) so I will at least vacuum fans and grills.

Thanks Again!

[snowmaker77]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

Oh I almost lost my mind - Cleaned fans, put back cover on, plugged in and hit the ON button... picture came up for 3 sec, unit shut off, power light blinked 11 times.
Pulled cover and tried - noticed I did not securely make one of the fan power connections. Plugged it in proper.

All set!

Will add - a friend recommended this product for connection lubricant:

[snowmaker77]

Re: Panasonic TH-42PZ80U Plasma Red Screen Issues

If this ever happens again, I'll use tape on that connector as well -- good idea. I have no experience with LG at all, but yes it seems a lot of people don't think highly of their tv's. I've fixed LCD's from Polaroid, Vizio, and Samsung, and plasmas from Panasonic and Samsung. Had a 42" Sanyo plasma that wasn't worth fixing since the buffers and Y-main all went out. Too bad the manufacturers can't come up with a way to prevent the buffers from taking out the Y-main, seems like it shouldn't be that difficult to do.

Any chance you remember exactly which connector on D board was the fussy one? My "red pix." problem just came back. A friend suggested the problem might be in a ribbon cable as he has seen this before.

Thank you!