This is an old 13" SVGA monitor. Last week my computer died.
Apparently the motherboard fried. The computer got slower and slower
for several days in a row and then it would not boot at all. The
harddrive is fine. I had another used computer and put my HD into
that computer. That worked fine. Whether this is coincidense or
fact, I am not sure, but right after that happened, my monitor started
acting weird. When I turn it on, the computer boots up and everything
is fine. About 5 to 10 minutes larter, the monitor gets very dim. I
can barely read it. Shutting it off does not fix it. However, a good
smack on the side of it with my fist gets the monitor back to normal
viewing. Sometimes I have to hit it several times before I can see
the screen again. After that, it stays working just fine as long as I
dont shut it off. However, I have noticed that it occasionally gets
slightly dimmer, but is still usable.

The brightness and contrast knobs are turned to max brightness and
they do nothing when the screen gets dim.

Since this is the only monitor I have and can not afford another new
one now, I just have to keep beating on it or I cant use my computer.
I plan to begin looking for another used one, but for now, this is all
I have.

I have puttered with electronics all my life, so I am not afraid to
open this thing and I know what to keep my hands off (high voltage
wire to CRT). Anyhow, I am not going to spend any amount of time on
this. I know there are millions of these old monitors around looking
for a home, but until I find one, is there anything that I might
check? A loose solder joint seems like a possibility, although I
really dont know how that could have developed after all these years
when I never move the monitor. I should mention that jiggling the
cable from the computer does not solve these blackouts either.

Anyone have any suggestions.

Thanks

Mark