2
\$\begingroup\$

Okay, I know this is an electronics Q&A site, and this question is mildly computer related. But I've got this problem with my VGA monitor, a graphics card and a computer. The problem is the video output is blurred in one direction quite badly. This looks very similar to a low pass filter - i.e. parasitic capacitance.

The confusing part is - this only occurs with one card, an Nvidia 9800 GT. I have a somewhat broken ATI card (GPU started melting and now all 3D games have misplaced polygons), and this doesn't occur. So I'm thinking something else is up with either the card or some configuration involving it. I've also noticed that there is an odd ripple to the black in the image. Could it be a ground loop? I'm using a cheap DVI to VGA adapter which could also be suspect.

I've attached an image of the problem.

Blurred in one direction

\$\endgroup\$

3 Answers 3

Reset to default
13
\$\begingroup\$

This looks exactly like VGA ghosting. This is usually caused by a long VGA cable. If you are only seeing it on 1 video card then I would suspect the video card is very poorly designed.

To add a technical note, the ghosting is usually caused from a mismatched line causing reflections and ringing which shows up as what you are seeing.

\$\endgroup\$
9
  • \$\begingroup\$ The cable is about 1.5m long. Is it possible to fix it? \$\endgroup\$
    – Thomas O
    Feb 1, 2011 at 21:15
  • \$\begingroup\$ @Thomas - Is it possible to fix the cable or the video card? I don't know about the condition of either, but I know that my Macbook Pro can drive a projector over a 20m cable, so this isn't normal. Is your cable integrated into the monitor (allowing you to test a different cable), do you have a different monitor, and/or do you have a laptop or other computer you can test the monitor and cable with? \$\endgroup\$
    – Kevin Vermeer
    Feb 1, 2011 at 21:31
  • 3
    \$\begingroup\$ it's possible that the suspect video card has poor or missing termination. \$\endgroup\$
    – akohlsmith
    Feb 1, 2011 at 21:33
  • 1
    \$\begingroup\$ If you only see it on one video card then I would guess its not the cable and would go with Andrew's suggestion of it having poor or missing termination. Sure it is possible to fix it. First thing that comes to mind is buying a new video card. \$\endgroup\$
    – Kellenjb
    Feb 1, 2011 at 22:23
  • 1
    \$\begingroup\$ @Thomas O They still really that expensive? I bought a 9800 GT a long time ago(over 2 years) for less the $150USD. I do have a question about your DVI-VGA converter, are you using it on your other setups also? \$\endgroup\$
    – Kellenjb
    Feb 2, 2011 at 0:30
2
\$\begingroup\$

As you have tried the monitor on two different cards, one it works with, the other smears the signal - this would indicate that the Monitor is OK and the video card is faulty.

I have seen this smearing effect on a very old video card, and it was caused by either a faulty DAC (Digital to Analogue Converter) or the smoothing caps around the DAC (And as the caps were quite old - the printing looked grey/brown instead of silver/white - an indication of age or overheating - When Caps get old - they loose capacitance and the ESR (Effective series resistance) increases.

\$\endgroup\$
0
\$\begingroup\$

Wohhh, now now, wait a bit right there.

The 9800 GT is a card made by Nvidia, who made the 8800 GTX ultra, the current 4XX cards, and other INCREDIBLY complicated and high end graphic cards. They most certainly did not "very poorly" design this card, besides, it is based on the 8800gt, which is pretty much the same card, and the 8800gt's were very popular and did not have much problems like this.

I suggest you first try to re install the newest drivers for your graphic card, which can be found on here. http://www.nvidia.com/Download/index.aspx?lang=en-us

Then, contact the location you bought it from, such as best buy or where ever you bought the card, and tell them you problem and for them to give you a new 9800 GT. If the stores says no for what ever reason, you can do a RMA with the brad that the graphic card is made from, such as EVGA, BFG, PNY or XFX. If it is neither of those, you contact Nvidia and also ask for a RMA. Most of the time this is a painless process, and you pay only for shipping the card to the company.

Here is a perfect site for computer hardware, it is called Newegg, and it provides you with computer parts for the cheapest you can find (most of the time), and it also has excellent customer support.

If you need further help, just ask on a forum such as this http://www.overclock.net/graphics-cards-general/

The people there are very helpful, and can practically hold your hand through the process.

Best of luck! though I think this question should be closed, because it seeems similar to other questions that are closed usually.

\$\endgroup\$
3
  • \$\begingroup\$ Actually, there is no evidence that the card is in fact made by nVidia or that the manufacturer decided to use the reference design. Further more you're talking about nVidia who made the 8000 series of self destructing cards. Also, stupid problems do happen to computer components and it is unsafe to assume that manufacturers do pay attention to what they are doing. For example, the newest Intel fiasco, silent withdrawal of several motherboard models by Asus few years ago and so on. \$\endgroup\$
    – AndrejaKo
    Feb 2, 2011 at 16:21
  • \$\begingroup\$ The card is not made by Nvidia: that is just the chipset/GPU, in fact the card was made by PNY. The card was given to me free, so I have no option of returning it. And it's certainly not a driver issue, as the problem occurs during POST too - it's entirely independent display resolution or mode. \$\endgroup\$
    – Thomas O
    Feb 2, 2011 at 17:03
  • \$\begingroup\$ Video cards are actually not that complicated, although they may seem that way, they just demand the highest end ram and GPU to keep up. \$\endgroup\$
    – Kortuk
    Feb 3, 2011 at 1:39

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.