Deformed image on CRT

[Endymion]

I have had a Sony PVM 2530 for about eight or nine years now, the entire time it has been in my ownership the top right of the screen has had a misaligned corner. I remember asking Lawrence about this untold aeons ago and he referred to it as a "topcurl." Whatever it's called typically, that corner of the screen is not even. It bends upwards and images that move across it deform in this fashion. It is not a vast area of deformity, and the colour is still perfect even in that spot. End result is that for all the time I've had the monitor I never messed with it.

A few years ago I first heard about this however, and wondered if it would fix the issue that the screen has. I have a total of four large CRTs right now, so I am less afraid of the consequences should I screw up the screen trying to fix it, but still, I'd rather not damage it if I can help it, and I am unsure from the photos and the description of the issue that this technique fixes would cure the problem the PVM has. I saw it demonstrated on Attack Of The Show two years ago when everybody was talking about this site, and a google around can find you a demo of it on video as well. The screens they show here though don't seem to have an image deformity but rather a spotty colour irregularity, randomly across the screen. The magnets seem to pick up the photons as they spin, and the most successful attempts I saw would drag the anomaly over towards the corner. As the magnetic field passed the edges of the corner, it would leave behind a properly laid image in its wake. Pretty bizarre, but it worked for those computer VGA monitors.

Has anybody here done this with a broadcast monitor like the PVM, or cured a "topcurl" with it?

[viletim!]

My guess is that this is geometric distortion caused by an imperfect apature grill (it's a trinitron isn't it?) inside the tube. It souns as if some tech at the manufactory spent some time adjusting the convergence so there isn't any colour distortion in the effected area at the expense of linear geometry. I'd just leave it alone, unless you prefer colour distortion over geometic.

BTW...the link refers to demagnitising a magnetised CRT, which is done by the monitor's internal degauss coil every time you turn it on.

[Ismail Saeed]

Reading further on that page, the author knows about degaussing but says this takes care of much huger issues than a regular degauss would.

Actually, I have a TV that this might help, but I'm not convinced that the nature of the problem is exactly the same.

I have a television which is definitely CRT (in that it isn't plasma or LCD, and was bought at least 7-8 years ago, or maybe even before then)...

When I was younger we had a TV that we had hooked a stereo to... basically, the RCA audio outs of the TV were hooked to the audio ins of this stereo so that its speakers did audio for us.  This was very nice, aesthetically.  We'd eventually stopped using that stereo for that purpose on that older TV, though.

I was playing some console games again around 1998/1999 (I bought an N64 for Ocarina of Time and became inspired to pull my other old consoles out of their storage spots in closests and cabinets) and I had the bright idea of hooking the stereo up to this (the one I'm speaking of in the present day) TV.  When I had been younger my older brother had hooked this stereo up to the older TV... now I knew enough to do this myself.  (For the record, this stereo had compact speakers that could be affixed to its sides, not giant speakers... both times we used it, we simply sat the whole thing down on top of the entertainment center the TV is in)

Anyway, I used this at first... but then I noticed that there was a discoloration in the upper left corner of the TV.  It showed reddish purple when the screen was solid blue, though the actual nature of the discoloration was to reddify whatever color WAS there a bit (hence the purple result on solid blue screens).  I found that the stereo was causing it, and that its positioning could alter if I shifted the position of the stereo and that it lessened if I moved the stereo further away.  Of course, the stereo was always going to be in proximity if it was in use, so I disconnected it since it wasn't worth having that problem (it wasn't surround or anything, after all)... I had hoped that the discoloration would go away once the stereo itself was nowhere near the TV, but the discoloration stayed in the upper left hand corner of the screen.

Here's the thing, though.  It's a WEIRD issue.  When you turn the TV on, the discoloration is there at the fullest intensity it can have, but if you leave the TV on for a good long while the problem dissipates... eventually becoming just a bit of edging along the horizontal edge in the very upper left of the  upper left corner, or disappearing completely and having normal color entirely.  After the problem is "gone" it stays gone, even if you turn the TV off and back on in a short timeframe.  However, once the TV has been off and at rest again for a while (say a few hours later or of course the next day regardless) then the discoloration again appears.

There have been times, if I don't want to even be initially distracted by the purply thing, that I turn the TV on prior to the show I want to watch or the game I want to play and leave it on while I go do other things and then come back to play.  However, this takes a lot of time, so it isn't always practical.

I imagine that it was interference, possibly magnetic, that caused this.  However, this was YEARS ago now, and that stereo is no longer anywhere near it.  No appliances near the system (a VCR, dish network box, and consoles at present) affect this spot at all... however, I'm not sure this solution would fix it, because it "fixes itself" over time while the TV is on just to come back again once the TV has been off a while.

With that in mind, should I try this on the TV for a possible permanent fix, or will that a) exacerbate the problem or B) prove unrelated?

I remember back when that we were quoted 50 dollars to get this fixed... which wasn't a bad deal, but it was a tiny enough issue and we're cost-conscious enough that we sort of didn't do that at the time, and eventually we just lived with it (esp. since  you can just wait and it goes away).  Fixing it myself, if this would fix it, would certainly rock.

[Endymion]

My guess is that this is geometric distortion caused by an imperfect apature grill (it's a trinitron isn't it?) inside the tube. It souns as if some tech at the manufactory spent some time adjusting the convergence so there isn't any colour distortion in the effected area at the expense of linear geometry.

The PVM screen is a Trinitron, says so right on the frame. The defect is not very bad, but it is very noticeable. I have complete confidence in saying that there is no way the unit shipped in this condition. You just don't sell screens this size in the dollar figure they asked for to get one with a distortion in a corner.

I'd just leave it alone, unless you prefer colour distortion over geometic.

Well that's what I've done all this time, but I am so sure that this defect happened after the unit left the factory, that I am wondering what caused it. If I knew how that happened, then I could better do something to fix it. The way the image is stretched across that corner sure makes it look as if a magnet may have warped it at some point. If there were an obvious way to correct the geometry manually, I guess I would try that first.

Reading further on that page, the author knows about degaussing but says this takes care of much huger issues than a regular degauss would.

Yes, it is the same process as degaussing, but because you're doing it manually, right at the points of issue, you have more control over it. The degaussing that is built-in to a monitor is very weak and goes across the whole screen by comparison. This is like using a sledgehammer to iron out the flaws, which is why it works in cases that a simple degauss-button would not, but also why you risk further damage to the screen.

With that in mind, should I try this on the TV for a possible permanent fix, or will that a) exacerbate the problem b) or  prove unrelated?

From what you have describe it is clear that the earlier exposure to your stereo/speakers warped the grille or shadowmask permanently. It may have been a pretty weak warp, but it is out of wack just enough to return to that position when the screen is off. When you turn it on and it warms, over time and the use of the guns it returns to its original state. The technique on that site would surely cure it if done properly, but again you run the risk of causing more severe and direct damage. If it is a spare TV, why not give it a go?

[Ismail Saeed]

From what you have describe it is clear that the earlier exposure to your stereo/speakers warped the grille or shadowmask permanently. It may have been a pretty weak warp, but it is out of wack just enough to return to that position when the screen is off. When you turn it on and it warms, over time and the use of the guns it returns to its original state. The technique on that site would surely cure it if done properly, but again you run the risk of causing more severe and direct damage. If it is a spare TV, why not give it a go?

Well, if it warped it permanently, can it actually be sent back just by doing this, or would it be a component replacement?

How sure are you that this would actually be a permanent fix?  I have to admit a 50 dollar repair cost does sound more attractive than permanently doing worse to it and having to buy a new TV.  The thing is, this isn't exactly a spare TV.  It's like, one of the two primary TVs.

To be honest I'd need components from someone else both to get the magnets and the drill, so it may cost me to try to do it myself anyway.

Oh, the emoticon in my prior post was supposed to be b) but you knew that :)

[viletim!]

Ismail Saeed,
It sounds as if you once magnetised some piece of metal inside the TV and it is, in turn, magnitising the CRT shaddow mask. Try degaussing the TV manualy. Not with magnets strapped to a high speed drill, that would just be silly. http://www.repairfaq.org/samnew/tvfaq/tvdegacrt.htm

Endymion,
Pro monitors are rountinely serviced throughout thier working life to keep them cabrated to pro spec. Maybe your monitor once developed the fault (maybe sombody dropped it!) and it was 'fixed' later on. Unless you bought it new...

[blackevilweredragon]

Ismail Saeed,
It sounds as if you once magnetised some piece of metal inside the TV and it is, in turn, magnitising the CRT shaddow mask. Try degaussing the TV manualy. Not with magnets strapped to a high speed drill, that would just be silly. http://www.repairfaq.org/samnew/tvfaq/tvdegacrt.htm

Endymion,
Pro monitors are rountinely serviced throughout thier working life to keep them cabrated to pro spec. Maybe your monitor once developed the fault (maybe sombody dropped it!) and it was 'fixed' later on. Unless you bought it new...

Actually, the magnet on a drill worked for my IBM 8512, that was horribly messed up after my baby sister got near it with a magnet...

I didn't think it would work, but with patience (about 2 minutes), it actually worked, and this monitor is still pure today...

[viletim!]

Oh, I don't doubt that it would do the job, I was just pointing out that using a bulk tape eraser or a poorly sheilded transformer is a bit safer to wave  around near a TV.

[Ismail Saeed]

Well, it doesn't naturally degauss... I could get a degaussing wand, but I'm hesitant to bring magnets up to this TV.  I was playing Zelda (Wind Waker) the other day and thought of it again, since I turned the TV right on and played it right away.  Someone mentioned weak magnets here...

Would it be safe to use a FRIDGE magnet to see if the discoloration moves around or warps any to see if these magnetizing solutions would even begin to get at this problem?  I imagine the worst case scenario for a fridge magnet is to just increase or move the issue slightly.

I'm skeptical of the off/on being a solution... I mean, this TV's been around for years, sometimes with its power cycled often and sometimes not... I would think that something like that would've already been done naturally.

[Endymion]

Off/on will degauss the unit.

As you have already discovered, it is too weak to cure the problem it has developed.

The problem is slight enough that it will go away after use.

The problem is existant enough that it returns to its improper state after it's been powered down for a while.

If you read the comments on the site I linked to you will find all sorts of adventuresome persons who used all sorts of things to correct their ills--including, no lie, a desktop fan! The electrical motor generates enough of a magnetic field to affect the screen. And yes, someone even used refrigerator magnets.

But even that would not guarantee that you will not screw up your TV's issue even worse than it's at now. Personally I would go for the magnets and a drill before trying anything less powerful. Did you see the video linked on the page? The movement of the field seems to be at least a part of why it's working as well as it does. I don't know how well an untrained hand could manage to fix the problem just waving a wand, a refrigerator magnet, or a desktop fan around.

[Ismail Saeed]

That's all well and good... but have you done this now?  Did it fix it?

[Endymion]

I haven't, no, but I don't have the colour problem that you do, either. I don't know that my unit's fault was caused by a magnet, we do know yours was. Right now I don't have a hard disk to take apart and other crap around the house is prioritising my time, but it's awful tempting to make the time and junk some perfectly good hardware. I'd be a lot more hopeful for yours than mine just because what you described more closely resembles the faults seen in the link.

[ido8bit]

If the color on your monitor is perfectly even in the distorted area I doubt that it is caused by that area of the screen being magnetised, so degaussing (regardless of the method used) isn't going to fix it.  

I'd be more inclined to expect a fault in the pincushion correction circuit, though without actually seeing the image it's hard to tell.  

I picked up a PVM2730 recently with far worse distortion.  I haven't got around the checking it out yet, but the pincushion correction circuit is the first thing I will be checking.  

[Ismail Saeed]

id08bit - is this in response to Endymion's description of his problem or mine?

[ido8bit]

Your color distortion was probably caused by placing the speakers to close to the TV.  The distortion remains even after the speakers were moved because some part of CRT was magnetised by the magnet in the speaker.  

Degaussing should fix your problem, but the built in degauss coil in the TV isn't strong enough to do it.  

You can degauss using a permanent magnet, but it comes down to trial and error and it could make the problem worse.  A fridge magnet is probably too weak to make the problem worse, but also too weak to cure it.  I have successfully degaussed a set using a larger permanent magnet, but it did initially make the problem worse and took several attempts before I got it right.  

I've also had some success using a degauss coil salvaged from a dead set on the face of the CRT.

I read the suggestion of attaching magnets to a drill.  I hadn't thought of that before, but I will try it next time I have a set that headed for the dump if it can't be fixed.