So I've got a Sun GDM-5410 21" CRT, about six years old.

It worked fine after I bought it used about six months ago. The "self-centre" button didn't accurately centre, but everything else worked, and that could have been my card.

Yesterday, the screen jumped shape and alignment significantly over previous days when I turned it on. About 1cm to the left, and half a centimetre down. Fine, I had meant to align it after replacing the video card, but was waiting until I replaced the current "temporary" card with something more permanent, but I set it right.

Today is weirder. I turn it on, and where I'd expect the usual solid-colour behind the "loading Windows 2000, wait" dialogue box, there were bright ripples from the corners in pastels. Colours were WAY off (yellow-green IE logo, a red wallpaper item was all colourful), and it looked like convergence was miles off.

I turned the monitor off and back on again, and it went back to normal, but strangely, it seemed to choose the size and position used before yesterday, the one which wasn't perfectly centred but not completely off-centre.

I also note it seems like you get a more pronounced "twang" sound when switching modes sometimes, but that could be my imagination, and it's been that way for a few days longer than the issues.

Is my poor monitor doomed? Has anyone seen this sort of glitchy behaviour before? I could see it as almost a "settings are being lost for some reason" thing because it lost all user-controllable attributes like convergence and shape.

just a stab in the dark, but did you degauss it ( should have a button for that), i had a sun 21 and it made a noise just like that, i got mine used and it just allways did that, my wife hated it but it seemed fine, also try not to put speakers right next to the monitor, i know you prolly allready moved them but i thought i would mention it.

hope this helps

If the clicking sounds are getting louder, maybe a relay is going bad. In CRTs, relays are used to switch between display modes, and one might be getting worn out.

Then again, it could just be fluke random glitches. I wouldn't get rid of it until it won't display anything.

- "degauss" it, like suggested....
- check the manual (if you don't have it, check the 'Net), you'd probably want to lower the "refresh rate"
on the resolution you chose.... some CRT's really dislike to be "operated" at too high a refresh rate....
this "odd behaviour" plus/and/or "piping & whistling noises"... are a clear sign of this...

Hope it helps!

TDR

Nothing whistles; I just noticed a "twang" when it changes modes; all CRTs do it, but the twang seemed a little more prominent.

It came on fine after being left off all afternoon, but I did degauss it for good measure.

Worst case scenario, I drag a 19" Trinitron out of retirement and start prowling the surplus yard for another good 21" CRT... I've seen some Dell P1110s, which I think are about the same as the GDM-5410 but without the stupid useless 13W3 plug...

I have it set for 1600x1200 at 75Hz. I know it can do higher if you turn off the "hide modes the monitor doesn't support"; it can do 85Hz at 1600x1200 and an array of better modes, all the way to 2048x1536 at 75Hz.