Panasonic Plasma TC-P55GT30 purple top half of screen

[sparkoneus]

Hi all. I am having an issue with my plasma for up to about 30 seconds after I first turn it on. After 30 sec's, the problem is gone until the set has been turned off for at least a few hours. I basically have this about once a day. As you can see from the pictures, the top half of the picture has some purple tinting/distortion. Depending on what's on the screen it is not that bad or pretty bad and it is exactly 1/2 (top) of screen. This leads me to suspect the upper y-buffer, but I have also read that the z-sustain leads to purple tinting. I have not heard of that really affecting only half of the display though. I'm thinking replace the upper y-buffer. I'd be interested in thoughts of those with much more experience than me. Thanks in advance.

[sparkoneus]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

Sorry, I was having trouble uploading pictures...attached now.

[tw2005]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

I'd be taking the back off , remove the Sc and ss boards, make sure the mount points are clean, check likewise the pads on the boards are good. make sure the screws are tight and firm against the board making good contact with the earth points.

I suspect this model also suffers from loose screws and or wrong type fitted.

If you look at this link, you'll see kits with new screws.

http://www.shopjimmy.com/catalogsear.../?q=TC-P55GT30

if you do this sooner rather than later it may save the boards blowing.

i've read stories where people have left it and after a while the Sc board shorts,, possibly also the Sd/su boards go too which I'd also make sure are earthed and screws tight but the screws also need to make good contact to earth all the boards correctly.

If the Tv becomes more reliable and stable after doing this then maybe look into new screws.

i have not touched any of that generation but I get the feeling from what Ive read if you address this now it may save the Tv .It's a theory but no harm in having a go before she blows.

[tom66]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

DO NOT RUN THE TV ANY MORE!
If you continue the SC board will be damaged increasing the expense of the repair.

[tw2005]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

DO NOT RUN THE TV ANY MORE!
If you continue the SC board will be damaged increasing the expense of the repair.

Yes, my thoughts too. Are you thinking bad earth /loose boards Tom?

[sparkoneus]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

Cool...this sounds like a good plan to me. I haven't read about anything that was quite like the behavior of my tv, but certainly willing to spend an hour or two on this, especially if it saves another board from blowing. This TV is only 3 years old, so this is a little surprising to me as I have an 8 year old 50" Viera that has never had a single problem. Thanks for the advice.

[tom66]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

Yes, my thoughts too. Are you thinking bad earth /loose boards Tom?

Yeah, first signs of ER circuit malfunctioning. This will kill SUS-UP/SUS-DN IGBTs which will then nuke the rest of the SC board. So it is absolutely critical that the TV not be used any more as no damage has currently happened but it may happen soon. How long, I have no idea.

[tw2005]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

Cool...this sounds like a good plan to me. I haven't read about anything that was quite like the behavior of my tv, but certainly willing to spend an hour or two on this, especially if it saves another board from blowing. This TV is only 3 years old, so this is a little surprising to me as I have an 8 year old 50" Viera that has never had a single problem. Thanks for the advice.

Get use to it, the newer models don't last . 3 years is probably a good run.

[tw2005]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

Yeah, first signs of ER circuit malfunctioning. This will kill SUS-UP/SUS-DN IGBTs which will then nuke the rest of the SC board. So it is absolutely critical that the TV not be used any more as no damage has currently happened but it may happen soon. How long, I have no idea.

Yeah, I guess easy for us to think along these lines but average person would persist with it until chernobyl.

[freakaftr8]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

I have a tc-p55ut50 that I bought new. 1 year later on its anniversary it blew an SU board. Guess my wife was watching it like this all day when I was at work. Then capped out w 7 blinks. Loose screws on the SU board. Luck fully I had a spare set with a cracked screen to replace the SU.
So agree with others. Check screws

[sparkoneus]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

Great...Thanks all for your input. Will pull it apart tomorrow if I have time and report back.

[freakaftr8]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

Btw. Noticed you watch fox news. I do too. That logo in the lower left corner will burn the screen. May I suggest using zoom format every once in a while to displace the logo. Or turn the contrast down. I can't stand channels with a fixed logo. It makes owning a plasma worry some even though I love them.

[sparkoneus]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

Yeah...Love fox, but that logo has been burned in already to a certain extent. I do try to use the scrolling anti-image retention bars every couple of weeks if I think about it and it work for a bit, at least helps to fade the logo, but it does come back. Also the banner across the bottom burns in (and I never even read that thing). I hadn't thought about zooming...that's a very good idea. For the most part, I don't really notice it on other channels and it does fade after a little while with anti-retention and running other channels for a while so it isn't a big deal. I didn't get to the TV today due to kids and yard work, but I did order a new set of screws for the boards, so when they come in I will open it up. I'm thinking about picking up a few used SC/scan boards for it just to have on hand in the future. They are cheap enough on eBay. Looks like I can get power supply/SC/both scan boards for about $100. Pulled from other TV's so not as good as brand new, but I could spare the $100 for the backup. Just a though...

[tw2005]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

Yeah...Love fox, but that logo has been burned in already to a certain extent. I do try to use the scrolling anti-image retention bars every couple of weeks if I think about it and it work for a bit, at least helps to fade the logo, but it does come back. Also the banner across the bottom burns in (and I never even read that thing). I hadn't thought about zooming...that's a very good idea. For the most part, I don't really notice it on other channels and it does fade after a little while with anti-retention and running other channels for a while so it isn't a big deal. I didn't get to the TV today due to kids and yard work, but I did order a new set of screws for the boards, so when they come in I will open it up. I'm thinking about picking up a few used SC/scan boards for it just to have on hand in the future. They are cheap enough on eBay. Looks like I can get power supply/SC/both scan boards for about $100. Pulled from other TV's so not as good as brand new, but I could spare the $100 for the backup. Just a though...

Just make sure you are getting the same revision boards, don't go by just the pcb board number but if they're from the exact same model then they should be correct

[sparkoneus]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

Quick update. For starters, this is the first time I have opened up a plasma. I removed the power and let sit for a day then pulled the back off. On this particular TV, the back panel is thin sheet metal and sharp enough to cut your fingers deeply (don't ask me how I know this), so use gloves. If the back doesn't come off without prying, then there is still a screw lurking somewhere. If you get all the screws out, the back comes off pretty easily. I stress again, watch the sharp edges.

I cleaned it out thoroughly and started checking the connections and tightening screws. All connections were very secure. Most screws were able to be tightened a little bit and I was careful not to overdo it. 3-4 screws on the SC board were extremely loose. I probably got a full turn and a half to 2 turns on 3 of them, less on a fourth. A couple of screws on the SU board seemed a little loose as well, but probably not enough to really cause a problem. I tightened every screw inside carefully to the point that I felt good contact was being made. Put the cover back on, connected everything and turned it on. The problem seems to be resolved. I say this with relative certainty because every time I have turned it on cold for the past three weeks or so the problem presents itself without fail. My sample size so far is only 1, but it worked fine the first time. Will report back in a week or two just to be complete.

Thanks for your input on this. probably saved me a couple of hundred bucks.

[tw2005]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

Quick update. For starters, this is the first time I have opened up a plasma. I removed the power and let sit for a day then pulled the back off. On this particular TV, the back panel is thin sheet metal and sharp enough to cut your fingers deeply (don't ask me how I know this), so use gloves. If the back doesn't come off without prying, then there is still a screw lurking somewhere. If you get all the screws out, the back comes off pretty easily. I stress again, watch the sharp edges.

I cleaned it out thoroughly and started checking the connections and tightening screws. All connections were very secure. Most screws were able to be tightened a little bit and I was careful not to overdo it. 3-4 screws on the SC board were extremely loose. I probably got a full turn and a half to 2 turns on 3 of them, less on a fourth. A couple of screws on the SU board seemed a little loose as well, but probably not enough to really cause a problem. I tightened every screw inside carefully to the point that I felt good contact was being made. Put the cover back on, connected everything and turned it on. The problem seems to be resolved. I say this with relative certainty because every time I have turned it on cold for the past three weeks or so the problem presents itself without fail. My sample size so far is only 1, but it worked fine the first time. Will report back in a week or two just to be complete.

Thanks for your input on this. probably saved me a couple of hundred bucks.

Good to hear. yes there tends to be a feather edge on the sheet metal and would slice, mine is the same and I have had a cut.

The SC board does resonate and can generate a buzz if loose and I have also generated that whilst testing a SC with screws missing. I don't do that any more for risk of bad earth.

If it was me i would have removed and confirmed no arcing or burn marks regardless to be thorough as these could still create a bad earth but sounds like you have saved it. A good lesson for other owners as prevention is better than the expense of repair.

What you found confirms exactly what Tom and I were expecting. maybe a dob on non permanent loctite may be a good long term fix as well.

[sparkoneus]

Re: Panasonic Plasma TC-P55GT30 purple top half of screen

Happy to report that this issue is definitely resolved. Kudos again for the folks on this forum who helped me out.