Have you tried powering off the monitor but leaving the computer running?
The "zapping" sound probably comes from the monitor high voltage and should
not be causable by any reasonable failure of the computer itself. (Also the
collapse of the video screen into a single dot further points to the same
condition.) After leaving it off for a short period turn it back on and see
if the system is still "booted up" and the display comes on.


"Marty" wrote in message
...

Sorry this is a long post. I hope someone will be persistent enough to
help me out.

I have been working on a friend's old Gateway 2000 GP6 (maybe G6?)
300MHz PII MMX system.

It has a problem where the video "zaps out" frequently. I say that
because the monitor literally makes a zapping sound as the screen
contents quickly collapse into a bright white spot and then it goes
black.

The video card in question is an ATI Radeon 9000 64M AGP card that was
installed by "some guy" a year or so ago because they needed to run two
simultaneous displays (one on the monitor and another on the s-video
output).

I have determined that after the problem occurs, the OS (Win98 first
edition) is not locked up. I can use the keyboard shortcuts to blindly
shutdown or restart the machine. However, the video will not come back
until the system is powered off/on (restart won't get it back).

The problem seems to occur when the system tries to display a lot of
white. For example, clicking maximize in a blank Internet Explorer
window will do it every time. I have also noticed that by starting with
a small IE window and dragging it bigger and bigger, the problem will
occur when the window has almost filled the screen.

First I thought this was a software problem (drivers or something), but
now I don't think so.

The Radeon manual says the system should have at least a 300-watt power
supply. This system only has 200W.

However, my friend insists that they did not always have this problem.
I'm not so sure. I don't think one would really pay attention to
wheteher they were doing things full-screen and/or what the color
content of the screen was.

Therefore I theorized that maybe the power supply had weakened over
time and what used to be borderline OK had become a borderline failure.
Miraculously, I happened to have a brand-new replacement power supply of
the exact same model (6500126) which I got stuck with on a prior repair
job. I tried the brand-new 200W supply and we still had the same
problem.

The peripherals in the machine, besides the Radeon card are 1 ISA modem
card, 1 ISA sound card, 1 HDD, 1 floppy, 1 Zip drive, 1 CDRW. These
components have all been there since before the Radeon card.

While I had the new power supply hooked up, I tried disconnecting the
Zip drive to see if that would give us the boost we needed but it did
not.

I cleaned everything out with a can of air so it should be cooling OK.
All fans appear to be fine and nothing feels hot to the touch. This
problem occurs even when the system is cold, however it may be a little
worse when it gets hot (this is what first lead me in the direction of
power supply).

Just for a test, I replaced the hard disk with another and installed
Win98SE from scratch (did not load ATI drivers). Even in this default
state, 640x480 with MS VGA drivers, the problem occurred as soon as I
maximized Internet Explorer. To me, this test eliminates software from
my possibilities.

So what do you all think?

Could the power supply cause something like this (especially since the
Radeon doc specifically asks for 300W)? I want to believe my friend
that "it used to work fine" but I just think most people don't always
pay that much attention.

Given the power supply theory, could it be the content of the screen
(i.e. mostly white) that pushes it over the edge?

I tried different resolutions and that did not help. It occurred to me
while typing this that one thing I did NOT try was disabling the
secondary display. Do you suppose that the combined content of both
displays trying to do "all white" is what draws more current than we
have available? When we ask the video card to run both displays, will
it need more juice?

Does it take more power for a video card to display more bright colors,
or white?

Lastly, I would like to try a beefier power supply but I am afraid to
hook up a standard ATX replacement. I've been under the impression that
Gateway used a standard ATX connector but the pinouts may be different.
The physical differences are obvious, but I may be able to do a little
drilling and fabricating to make a standard ATX supply fit physically.
It's just the electrical (pinout) part that scares me. I don't want to
fry my friend's machine.

If you've read this far, THANK YOU VERY MUCH IN ADVANCE!

-Marty


--
Marty