As the subject states I have a 21" sun monitor that has a greenish color in
the upper right and lower left corners. Each is a roughly triangular area of
about 2x3 inches.

I'm trying to try and figure out what is causing this so I can fix it.
So,

1) Has anyone seen this sort of thing before? Is it a known problem?

2) Is the cable (I am using a rather cheap (free) HD15-HD15 cable) a
possible cause? If so would an adapter for the 13 pin fixed cable be a
better idea?

3) Is degaussing a possible solution? I have pressed the degauss button a
few times but did not notice a difference.

4) Some posts have recommended opening the back and adjusting the pots on
the crt. I can see how this would help if the color was screwed up across
the whole screen but I'm wondering if it would be effective in this
localized situation.

5) Is this a symptom that the monitor is just "worn out"?

Any help or ideas of where to go next appreciated.
Thanks.

-Jack

Shadow mask/aperture grille shift, (in which case there is no cure
except to replace the picture tube), or possibly the unit's degaussing
coil circuit isn't working efficiently. If this is the case, you MIGHT
have some success "ironing out" the problem by applying a medium
strength magnet to the picture tube face in the affected area. (While
it's turned on and displaying a white screen, ideally.) This will screw
up the colors in the area of the magnet, but if you play around with it
and practice for a bit, you will be able to control what you're doing
and maybe correct the problem. And then, with that defect taken
care of, turn the monitor off, let it sit for a while, and turn it back
on and then the degaussign circuit should fix the rest.

If the problem still remains, you have the aforementioned shifted
shadow mask or aperture grille in the picture tube itself, which is
not repairable.

CJ


me wrote:
> As the subject states I have a 21" sun monitor that has a greenish color in
> the upper right and lower left corners. Each is a roughly triangular area of
> about 2x3 inches.
>
> I'm trying to try and figure out what is causing this so I can fix it.
> So,
>
> 1) Has anyone seen this sort of thing before? Is it a known problem?
>
> 2) Is the cable (I am using a rather cheap (free) HD15-HD15 cable) a
> possible cause? If so would an adapter for the 13 pin fixed cable be a
> better idea?
>
> 3) Is degaussing a possible solution? I have pressed the degauss button a
> few times but did not notice a difference.
>
> 4) Some posts have recommended opening the back and adjusting the pots on
> the crt. I can see how this would help if the color was screwed up across
> the whole screen but I'm wondering if it would be effective in this
> localized situation.
>
> 5) Is this a symptom that the monitor is just "worn out"?
>
> Any help or ideas of where to go next appreciated.
> Thanks.
>
> -Jack
>
>