This is not a "help me fix my monitor" thread. This is on a computer monitor, but is a general CRT question involving the way one works. I appologize if this doesn't belong here.

I just bought a Dell Ultrascan P991 (sony manufactured trinitron type flatscreen CRT) on a thrift store run. Picture's great, but blurry in some areas, and text ghosts to the right. Using the Convergence control in the menu, I got it looking moderately OK.

While shutting down a Knoppix LiveCD session, I noticed the problem. Some blue was peeking out from behind a string of pink text at the bottom of the screen, so I adjusted the convergence accordingly. Then I noticed that the pink text at the top off the screen was WAY off. In windows, when i fix the top of the screen, the lower half goes blurry (varied, kind of gradient from center to bottom)

So, it would appear that there is a convergence problem with the hardware, leaving discrepancies in different areas of the screen, and no front panel tweaking can fix this. Now, here is my question: Could this be a component or circuit problem, or a terminal problem with the tube? I know certain products from this era are notorious for bad capacitors, but i haven't heard anything about monitors. I've degaussed it about seven times already, too.

Many thanks for any info.

I wonder if it might have been dropped or it fell in such a way that the aperture grille behind the screen might have gotten damaged, causing the beams not to hit the right phosphors?

It came from someone's office (email server note and several plushie KISS ME stickers), and it came from Salvation army, so it's hard to tell. It was in the back of my minivan, and while I still need to work on taking off smoothly (new driver), I don't think I moved the monitor an inch.

I also just noticed a geometry problem that I though I corrected, but that doesn't seem so. The top half of the screen is alighned perfectly (going by edges and the 2 stabilizing wires), but the bottom half is in kind og an arc, about the height of a line of text. Aperture grille damage is irrepairable, correct?

I think an aperature problem would affect purity rather than geometry or convergence.

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Don't know if they used a "self-converging yoke". If they did, turning the yoke left/right or up/down (I mean pitch and yaw, not twisiting around the axis) could cause convergence problems without necessarily causing purity problems (which would occur quickly if the yoke slipped backwards or forward of the correct position). If no-one comes up with real info, take a look and see how the yoke is mounted and if it has some sort of shims to control its position.

The Sony WEGA tube is known for convergence and purity issues... As far as the text ghost, that could be your monitor cable. Unfortunately, I don't think it's removable. Try moving the cable around to other positions, and make sure it isn't coiled or wrapped. It must be as straight as possible, or it will act like an inductor or transformer and cause ghosts!

Charles

I have found bad capacitors in the horizontal section and/or EW correction (if present) can cause geometry problems that can't be corrected by adjusting controls. I haven't seen your the monitor so I can't say if this the problem in your case.

I use a Sony Multiscan E215 FD-Trinitron monitor at the moment. I was offered the Trinitron for "any working monitor". They only needed it to test computers anyway. I also have a Nokia Valuegraph 447B from 1994 with a Trinitron tube. It supports 1024x769, but gives best picture at 640x480. And it´s very heavy and uses a lot of power.

i have repaired those on campus here,there is a service menu,and you have to have sony's software and cable to properly set up this monitor,someone may have tried this and gave up as it is kinda tricky,i have one of those on my desk at work,i will not let them give me a LCD monitor,i prefer the detail and sharpness of this monitor..my res is set at i think 1280x1024..its real sharp and nice,perfect gray scale,perfect geometry.
you may want to just check the yokes and wedges on the neck..
also you can not use a regular degaussing coil to degauss,you will in fact "MELT" the aperture grill..maybe some has done that..sony has a bulletin
warning about using deguassing coils on this series of fine mesh CRT's
good luck!..(my typing sucks this morning),I have only found shorted F.E.Ts,and on the ones that are left on "cooking" 24hrs bad capacitors..the chassis is kinda hard to remove and work on..if i remember you cant even set G2 unless you are in the service mode with their software,so you are very limited to any type of adjustments without sony's parallel cable..yeah it sucks..it hooks to your parallel port on ur computor..it was a $300.00 cable..with software,i had to dig it all out and look at it again