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ScanDisk
December 18th, 2017, 03:21 PM
I got this "new" old 1992 vga monitor in for m 286 and it works great, but it has two points of slight discolouration at the top right corner and also the middle of the left side.

It's often not noticeable, but it is most obvious when red is being displayed on the screen, like this picture of Wolf3d:

https://scontent-ort2-1.xx.fbcdn.net/v/t1.0-9/25399174_10211158619065503_5090298472348929585_n.j pg?oh=5ea06feb37421ad2d4f847f5106025d1&oe=5AB828C0

I wonder though, is there any not too hard things I could do to mitigate it or get rid of it, or is it something I'm just gonna have to live with?

EDIT:

After

https://scontent-ort2-1.xx.fbcdn.net/v/t1.0-9/25591855_10211182733188341_6729575368212664732_n.j pg?oh=0b65194bd1c73ca14c8cf62492d3f63d&oe=5AC0C5A8

Stone
December 18th, 2017, 03:32 PM
Try degaussing it manually.

ScanDisk
December 18th, 2017, 05:51 PM
Try degaussing it manually.

I've talked to my father, he said he has a soldering gun.

The special degaussing tools on ebay seem a little to expensive to justify buying for a single use, would you say that the soldering gun method described here should suffice? :

https://www.wikihow.com/Degauss-a-Computer-Monitor

KC9UDX
December 18th, 2017, 06:05 PM
Maybe. There's one way to find out.

Chuck(G)
December 18th, 2017, 08:05 PM
A VHS videotape degausser should also work a treat.

KC9UDX
December 18th, 2017, 08:20 PM
A VHS videotape degausser should also work a treat.

Yes but they can be a little too strong if you're not careful or prepared. I had been using one that was apparently dying for years, and it worked great. But it finally gave up the ghost so I bought one just like it to replace it. Upon the first use of that one I dislodged the shadow mask of a 25" Curtis Mathis.

Chuck(G)
December 18th, 2017, 09:53 PM
Medio tutissimus ibis -- Ovid.

SpidersWeb
December 19th, 2017, 12:47 AM
I have a display "new in box" that does this also, it'd been opened, but the monitor was as new with even the little cable tie on the VGA connector. It also has a discoloured patch. I have a degauss wand I've used on other monitors, but on this it always reverts to that same discolouration afterwards.

My theory is someone dropped the box and screwed up the setup (magnets got misplaced or a ring got rotated). Not sure if this is the case with yours, but wanted to mention that. Local TV repair stores want nothing to do with anything that isn't worth > $2000, so I can't check with them.

KC9UDX
December 19th, 2017, 01:22 AM
It's not unusual to find this kind of "permanent" convergence error on tubes that have been stored a long time (not being regularly degaussed) or transported (being subjected to greatly varying magnetic fields or acceleration stress).

In my experience I put these causes in order of prevalence:
1) just magnetism beyond what the attached degausser can deegauss (if it even has one).
2) out of specification electrical components in convergence correction circuitry (mostly capacitors).
3) mechanical trouble that can be corrected (loose magnets). If the only magnets are adjustable rings on the neck, these generally only are an issue if someone altered them in the past.
4) mechanical trouble that cannot be corrected (damaged or dislodged shadow mask, damage usually being distortion from heat).

ScanDisk
December 19th, 2017, 01:46 AM
I'm gonna try a simple degaussing today after I get home from work, hopefully that fixes things. Hopefully.

It seems my safest bet though is to see if the repair shop I use, or my father uses can degauss professionally preferably with a degaussing tool.

Stone
December 19th, 2017, 03:35 AM
I have an old television degaussing coil something like this:

https://www.ebay.com/itm/NEW-CRT-MONITOR-DEGAUSSING-COIL-Arcade-TV-Repair-/120966975586?_trksid=p2349526.m4383.l4275.c10
https://i.ebayimg.com/images/g/CkcAAOxyKsZRwenD/s-l500.jpg

ScanDisk
December 19th, 2017, 03:14 PM
So I ended up using the soldering gun method,

it did the trick, in real life you can still see some discolouration in the top right corner if you look for it, but it's a lot less and you have to have known it was there before to really notice it.

So it seems deguassing did help quite a bit, maybe when I get my hands on a proper tool, or something which can generate an even more powerful magnetic field than a soldering gun, I will try it again.

Would continuing to degauss it with the soldering gun yield any more results or is this the best the soldering gun can do? Does it matter how many times I do it?

https://scontent-ort2-1.xx.fbcdn.net/v/t1.0-9/25591855_10211182733188341_6729575368212664732_n.j pg?oh=0b65194bd1c73ca14c8cf62492d3f63d&oe=5AC0C5A8