Question about TVs and degaussing.

[Jae200]

Well, not really about degaussing, I guess. I turned on my cabinet this morning and  ran GameEX cycling through the games I have, loading one randomly thinking that that would act as sort of a screen saver and wouldn't burn in my TV. I was on it a little while ago and noticed a discolored patch on the screen which would indicate that it needs degaussing.. I turned it off for about 30 minutes, then back on and the patch was gone, but at first it scared me since I've only had my project finished a couple of days and didn't want to see this. Any ideas what might have caused this? I haven't moved the cabinet much from the general area its in so changing magnetic fields doesn't seem likely. Could heat play a part? The air around the TV inside the cabinet was warm but not hot and the cabinet has some ventilation.

[Jae200]

Well this is strange. I turned the TV back on and it was fine then walked away for a few minutes while I copied files off my other computer and went back and I could see the problem cropping up again but not as bad as it was but got progressively worse. My computer is on its side under the TV with my subwoofer sitting on top of it. The monitor stand is above it obviously but I was thinking the closeness to the computer/sub may have something to do with it. Is that possible?

[MikeDeuce]

Try moving the sub... Most traditional speakers contain magnets... I don't think PC-speaker subs are typically shielded because they're intended to be on the floor.

[Jae200]

OK I've been trying to troubleshoot the problem and did just that.. I moved the sub into the lower part of the cabinet underneath the computer and its still happening. Taking a closer look though, my power supply is mounted on a block of wood directly under the TV. I put it there originally thinking that it would be fine but the TV is bigger than I expected. Could this be the problem? It seems to be happening faster and faster.. Part of the screen becomes washed out within minutes of turning the TV on.

Try moving the sub... Most traditional speakers contain magnets... I don't think PC-speaker subs are typically shielded because they're intended to be on the floor.

[Jae200]

This problem may not be a problem at all.. But I still don't understand it at all. I had GameEX setup so it wasn't running fullscreen with Notepad in the background and the washed out spot was over Notepad.. I loaded and ran a game and the washed out spot disappeared completely, exit the game and it slowly reappears in the same spot. I closed GameEX and Notepad both and the spot slowly seems to be disappearing. What the hell? But as long as this doesn't happen when playing games I don't see it as a problem.

[surf]

I'm using a 27" TV in my cab, and occasionally it will have a lighter tone/color in the middle left of the screen.  Dunno if this is because it's a cheap Wal-Mart TV or what, but usually after turning it on and off again, it works just fine.

I have my subwoofer and computer on the bottom of the cab, about a foot below the TV...

Could just be a cheap TV like mine...

[NIVO]

how close is your flourescent light to the tv? if you have one that is.

[Sensei]

Some televisions (especially RCA ones) have internal interference which can cause anything from color splotches to diaganol lines or washed out areas (as if the brightness were turned up and the contrast turned down....but only in specific areas).  A lot of times it only crops up once the internals have warmed up.  (This may explain why it only sometimes occurs, especially after running for a while).

This is a known problem with specific models or CRT type televisions.

Now if you've gone and done all the troubleshooting you can by removing any electrical/magnetic sources of interference then perhaps you're looking at an internal problem...ie: Surf's answer

Could just be a cheap TV like mine...

Unfortunately, many televisions are sold knowing this is a problem.  In fact many models of televisions have specific repair kits to fix internal interference.  BUT....of course they choose not to fix it unless someone complains.

So it's easy if your television is still under warranty.  Call up a repair shop, give them the make and model of the television and they can tell you if there is a repair kit for it.
If it's not under warranty, I guess you could still do this but it's out of your own pocket.

So if you're baffled and you've done everything you can......

I hope it's on warranty

Just my $0.02 worth.

Good Luck

[Jae200]

The TV is a Samsung. Don't know how bad it is.. This can't hurt the TV in the long run can it? I'll play with it tomorrow and see what happens. If it doesn't happen during games though, I'm not going to worry too much about it but I think I might move the power supply just for easier access. I'd say the flourescent light is probably a foot away from the TV. Too close? I'm not sure what to do with that since I can't change the height of the TV or move the light. I may check into repair kits though. The TV is brand new.. Just bought it for this project. Thanks for the help!

[ChicagoDave]

I have a similar problem with my 27" Mitsubishi TV using the s-video input.

It seems to be the same as this thread:

http://forum.arcadecontrols.com/index.php?topic=34881.msg303391#msg303391



I've heard this refered to as "doming".

[Jae200]

Hmm. I'm using Svideo too. Thanks for the link. I'll check into that. That does sound like the problem I have. The burn mark was over Notepad which is white and the blue bar at the top turned green. As far as the brightness goes.. I put in a dark piece of plexiglass that came with the old cabinet and turned brightness up to 60 from 50. Don't think thats bright enough to cause any problems. I'll see what my options are as far as video inputs and see about using something other than Svideo. I believe I have component jacks.

[ChicagoDave]

Hmm. I'm using Svideo too. Thanks for the link. I'll check into that. That does sound like the problem I have. The burn mark was over Notepad which is white and the blue bar at the top turned green. As far as the brightness goes.. I put in a dark piece of plexiglass that came with the old cabinet and turned brightness up to 60 from 50. Don't think thats bright enough to cause any problems. I'll see what my options are as far as video inputs and see about using something other than Svideo. I believe I have component jacks.

Let me know how it works out.   Thanks!