Bad screen image. Monitor or video card or what?

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I often have a bad screen image on my CRT monitor (KDS brand) , which
up until now had worked fine for years.    It's in a Dell Dimension
4600 iirc.   Running XP Pro with 4 gigs RAM.

I figure the problem is the monitor or  the video card, but perhaps
there is a third possible cause??????  That's my big question.   Is
there a 3rd possible thing that couldd be failing.

Details:  After, it often seems, everything has time to get hot,, hot,
there are a lot of red dots on the screen, sometime short vertical red
line segments, and some red lines from top to bottom.   When at that
point, I hibernate, green appears in part of the are ofthe big word
WINDOWS that should be white.

The video card is an ATI RAdeon 7000 64MB TV-out 130TO02004245.

I had bought one of these for another computer, when I needed a better
video card for some reason, and when I got this computer, I found 3 of
them for 10 or 20 dollars total.   I guess they were used cards, sent
to me wrapped in bubble wrap.    I used the first one for a couple
years until the symptoms above started.   I tried turning off only the
monitor, but that didn't seem to help.    Turning the computer/monitor
off did help, but eventually not for long.

So a couple days ago I changed to the 2nd of the 3 cards.   Two nights
ago I left the computer on all night and still it worked for hours
yesterday morning.  Last night, the computer was off all night, but
only worked right for 10 minutes.   So I've begun to have doubts that
it is the video card.  

 I hadn't put the side cover on the computer yet.  Could that be
making the card warm up much faster than it would with the cover on??
(There is another card two slots away, but other than that, it's not
near much of anything.   It has a heat sink that's 1.5" x 1.5" x
almost 0.5" high.    No fan.

Thanks a lot.

Re: Bad screen image. Monitor or video card or what?

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It sounds like a heating problem,
try to fing a fan, and let it sort of blow at  the hottest part
of the card.

Re: Bad screen image. Monitor or video card or what?

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Thanks.   I'll try that.   I have a 4 inch fan that is perfect for

And also you are saying it's got to be the the card or the monitor?
There's no third secret place that could malfunction without other
things malfunctioning?

.  (The sound works fine, microphone works fine, the programs work
fine. )

Re: Bad screen image. Monitor or video card or what?

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The card.

Re: Bad screen image. Monitor or video card or what?

Sjouke Burry wrote:
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Yup. CRT plus short vertical lines, equals card.

The CRT can "discolor" the whole screen. That's a gun problem.
The CRT scans horizontally. So if the CRT was screwing up,
there would be a horizontal aspect to it.

It's harder for the CRT to exhibit vertical artifacts. Like, a vertical
line in the center of the screen. If the CRT had an OSD (on-screen display),
I suppose a screw-up in the OSD could do it. But what are the odds
of that happening ?

An LCD on the other hand, there have been cases of saturated, full
height colored vertical lines. So that's a known failure mode for
them, and something you might expect.

So each display device, has failure modes that are "natural" for
them, and other modes that would be very hard to create.

In the case of CRT plus short vertical lines, that leaves the
video card as the culprit. And overheating is one failure
mechanism on a video card.

You also want to inspect video cards, for bulging capacitors.
And conversely, look for a bulging capacitor near the AGP slot
on the motherboard itself. In some cases, just the AGP slot capacitor
fails, and the other caps on the motherboard are OK. I don't know
if that cap is part of a switching power circuit, or the cap is
there as a bypass solution. But occasionally, that one is bulging.
A bulged cap, is no longer going to filter the way it used to.


Re: Bad screen image. Monitor or video card or what?

On 1/31/2013 1:51 PM, micky wrote:
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What sort of connect are you using between the card and monitor? Your
description of red dots and lines makes the problem sound digital and if
you are using an analog connection between the devices then I'd be inclined
to say that it is the card or the bus it is plugged into or the chipset
which is driving that bus. You say that the problem happens with more than
one video card so that suggests that the problem is external so the bus or
chipset come to the fore. The symptoms also make it seem heat-related. That
leads me toward the chipset. Does yours have a chipset fan on the heatsink
and is it starting and running consistently?

Re: Bad screen image. Monitor or video card or what?


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Just the cable that comes out of the CRT monitor, with a 13 pin
connector on the end.  That is  5/5/5.

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Wel, that's two more parts than I h ad thought about!!

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On my old compuer that I assembled myself, I knew where the parts
were, but with this Dell I've sort of ignored the insides.   I will
find the manual and answer your question.  There is a chip in the
middle of the board with a non-fan heat sink, a bit over an inch
square with a lot of rectangular metal rods sticking up 3/4".   --
well I found the manual on pdf and it ignores the space where that
chip and heat sink are. It shows it as empty, sort of like a map of
North Korea.  But the second biggest chip on the board, smaller only
than the CPU, is the one you mean, right?

Also    I went upstairs but forgot to get the fan, to cool off the
obard, or maybe this chip.)

I should add that in the last 4 hours, intesting things have happened.
For a while a lot of the white areas were pink, like the white text in
the blue bar at the top of the Firefox screen (but not pink or less
pink in the blue bar at the top of other program screens)

And now -- running XP -- there are red vertical lines in the task bar
and systray at the bottom (which I have set to double height) that run
from the top of the task bar to the bottom of the screen , every half
inch side to side, but no red lines or dots elsewhere on the Agent
screen or Eudora or Firefox or a couple other programs that are
running full screen.

But neither of these strange t hings has made it hard to read what's
on the screen, so I've gotten a lot of work done, on this and other

Somewhere I have a can of aerosol coldness, that I could spray on the
heat sink , or the board heat sink and see if the image improves.  Is
that a good idea???


Re: Bad screen image. Monitor or video card or what?

micky wrote:
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99% chance that it's the card. I've come across many cases
with the symptoms you described and they all originated from
the video card. As already discussed, the best way to make
sure is to cool the card's heatsink with a spray or a fan.

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