I would also test these cards on another monitor and/or other VGA cable might be better/more compatible. But usually CRT monitor solves like 99.99% such problems.

Yeah make sure you have a shielded VGA cable, a good one, it makes a difference for me.

Is the first one really a sign of a VGA cable issue? I've tested probably 30-40 cards on this particular monitor and cable in this exact location in this same computer over the last few months and I've only experienced this issue on maybe two or three cards and it does it at every resolution, in DOS and Windows.

With regard to the second one, I have two identical cards on hand and one has the wavy pattern, while the other doesn't. Seems odd that it would be caused by anything except for a defect on the card.

Dark smearing across the screen: Saw this on a GeForce 256 and have heard from a few other people about their GF256s doing this as well. I'm not sure about the root cause, but I think it's DAC degradation. I experimented with fixing it by replacing the VGA connector and doing RGB signal buffering before it launches into the cable but neither approach helped even a little.

Ripples on the screen: In some cases you can get this from having really bad decoupling capacitors on a card. When it's just at one particular resolution and on an LCD, that might be a little funky synergy between the card's DAC and the monitor's sampling frequency/phase.

Ozzuneoj wrote on 2023-02-17, 17:47:

Is the first one really a sign of a VGA cable issue? I've tested probably 30-40 cards on this particular monitor and cable in this exact location in this same computer over the last few months and I've only experienced this issue on maybe two or three cards and it does it at every resolution, in DOS and Windows.

With regard to the second one, I have two identical cards on hand and one has the wavy pattern, while the other doesn't. Seems odd that it would be caused by anything except for a defect on the card.

Well you could say the cable and card aren't matched. Either it is a signal integrity issue that the card didn't make enough attempt to avoid by a more paranoid design, or the cable is too good or just the right (wrong resonant) length resulting in a card that gives a robust signal making a lot of undamped reflections up and down the cable.

Edit: It could possibly be the case that the card bracket doesn't actually screw into the ground plane on the card, and the card is relying on backplate to chassis contact to provide the shield ground connection. If this is the case then a card plugged into a loose motherboard or not fully screwed into a case may exhibit this behaviour.

Signal cable has no shielded wires for the RGB signals hence bad signal reflections. Change to quality cable and they will be thicker too.

Believe me, seen this before. At one shop I worked for once, a owner used a cheap extension VGA cable, told him to change it to quality cable as described and this noise disappeared.

Cheers,

pancakepuppy wrote on 2023-02-17, 18:26:

Dark smearing across the screen: Saw this on a GeForce 256 and have heard from a few other people about their GF256s doing this as well. I'm not sure about the root cause, but I think it's DAC degradation. I experimented with fixing it by replacing the VGA connector and doing RGB signal buffering before it launches into the cable but neither approach helped even a little.

Ripples on the screen: In some cases you can get this from having really bad decoupling capacitors on a card. When it's just at one particular resolution and on an LCD, that might be a little funky synergy between the card's DAC and the monitor's sampling frequency/phase.

Yes, for that first problem I was thinking along the lines of it being a DAC issue of some kind, but the specifics of that are beyond my expertise. I'm assuming that since the RAMDAC seems to be integrated into the TNT2 (and most other newer chips), it is basically game-over for this card, right? I can't see any way it would be fixable if the RAMDAC is failing for one reason or another.

Is there a possibility it is related to bad caps?

BitWrangler wrote on 2023-02-17, 19:19:

Ozzuneoj wrote on 2023-02-17, 17:47:

Is the first one really a sign of a VGA cable issue? I've tested probably 30-40 cards on this particular monitor and cable in this exact location in this same computer over the last few months and I've only experienced this issue on maybe two or three cards and it does it at every resolution, in DOS and Windows.

With regard to the second one, I have two identical cards on hand and one has the wavy pattern, while the other doesn't. Seems odd that it would be caused by anything except for a defect on the card.

Well you could say the cable and card aren't matched. Either it is a signal integrity issue that the card didn't make enough attempt to avoid by a more paranoid design, or the cable is too good or just the right (wrong resonant) length resulting in a card that gives a robust signal making a lot of undamped reflections up and down the cable.

Edit: It could possibly be the case that the card bracket doesn't actually screw into the ground plane on the card, and the card is relying on backplate to chassis contact to provide the shield ground connection. If this is the case then a card plugged into a loose motherboard or not fully screwed into a case may exhibit this behaviour.

Sounds logical to me. What part of the card would a manufacturer beef up to reduce the chances of this happening? Maybe whatever that is is either different or broken on the card exhibiting the issues. Still, I will try a different cable. I just don't want someone else to have an issue with this part if I move it along to a new owner at some point.

pentiumspeed wrote on 2023-02-17, 19:58:

Signal cable has no shielded wires for the RGB signals hence bad signal reflections. Change to quality cable and they will be thicker too.

Believe me, seen this before. At one shop I worked for once, a owner used a cheap extension VGA cable, told him to change it to quality cable as described and this noise disappeared.

Cheers,

Which noise are you talking about, the second one?

I will definitely try a thicker cable on my test bench.

Both of those screenshots look like unshielded cable artifacts to me. Make sure your cable has the ferrite cores on it too.

Ozzuneoj wrote on 2023-02-17, 20:38:

Yes, for that first problem I was thinking along the lines of it being a DAC issue of some kind, but the specifics of that are b […]
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pancakepuppy wrote on 2023-02-17, 18:26:

Dark smearing across the screen: Saw this on a GeForce 256 and have heard from a few other people about their GF256s doing this as well. I'm not sure about the root cause, but I think it's DAC degradation. I experimented with fixing it by replacing the VGA connector and doing RGB signal buffering before it launches into the cable but neither approach helped even a little.

Ripples on the screen: In some cases you can get this from having really bad decoupling capacitors on a card. When it's just at one particular resolution and on an LCD, that might be a little funky synergy between the card's DAC and the monitor's sampling frequency/phase.

Yes, for that first problem I was thinking along the lines of it being a DAC issue of some kind, but the specifics of that are beyond my expertise. I'm assuming that since the RAMDAC seems to be integrated into the TNT2 (and most other newer chips), it is basically game-over for this card, right? I can't see any way it would be fixable if the RAMDAC is failing for one reason or another.

Is there a possibility it is related to bad caps?

BitWrangler wrote on 2023-02-17, 19:19:

Ozzuneoj wrote on 2023-02-17, 17:47:

Is the first one really a sign of a VGA cable issue? I've tested probably 30-40 cards on this particular monitor and cable in this exact location in this same computer over the last few months and I've only experienced this issue on maybe two or three cards and it does it at every resolution, in DOS and Windows.

With regard to the second one, I have two identical cards on hand and one has the wavy pattern, while the other doesn't. Seems odd that it would be caused by anything except for a defect on the card.

Well you could say the cable and card aren't matched. Either it is a signal integrity issue that the card didn't make enough attempt to avoid by a more paranoid design, or the cable is too good or just the right (wrong resonant) length resulting in a card that gives a robust signal making a lot of undamped reflections up and down the cable.

Edit: It could possibly be the case that the card bracket doesn't actually screw into the ground plane on the card, and the card is relying on backplate to chassis contact to provide the shield ground connection. If this is the case then a card plugged into a loose motherboard or not fully screwed into a case may exhibit this behaviour.

Sounds logical to me. What part of the card would a manufacturer beef up to reduce the chances of this happening? Maybe whatever that is is either different or broken on the card exhibiting the issues. Still, I will try a different cable. I just don't want someone else to have an issue with this part if I move it along to a new owner at some point.

pentiumspeed wrote on 2023-02-17, 19:58:

Signal cable has no shielded wires for the RGB signals hence bad signal reflections. Change to quality cable and they will be thicker too.

Believe me, seen this before. At one shop I worked for once, a owner used a cheap extension VGA cable, told him to change it to quality cable as described and this noise disappeared.

Cheers,

Which noise are you talking about, the second one?

I will definitely try a thicker cable on my test bench.

These are the smearing from cheap cables. Get thick one they'll have shielded coaxes for RGB signals. I have seen this before, trust me. Not the video card themselves, I have not seen any that made the smearing ever even on cheap ones if using a quality cable.

Cheers,

I've seen similar with my 8800GT when I used it with DVI>VGA adapter. Other cards with the same adapter didn't have the same issue.

Well, I'm sad to say that neither of these is caused by the cable or the monitor, but I wasn't really expecting it to be in this particular situation.

One card always has the smearing\ghosting as shown in the first image. The other card always has the wavy pattern at 800x600 and 1024x768. So far, I have tried:

3 VGA cables. One basic modern cable with a moderate wire gauge and small ferrites. One older but very heavy black cable with medium sized ferrites. One older but very heavy gray cable with blue ends and huge ferrites. All totally different types of cable, and all exhibit the same issues.

2 monitors. One Dell Ultrasharp 2001FP (4:3 1600x1200 IPS LCD). One HP N246V (24" 1920x1080 IPS). Tested both monitors with the same cables. Just swapping cables from one monitor to the other while the system is running so I could easily note any changes... but there were none, no matter what I do with the cables.

The Dell does allow me to adjust the pixel clock which causes the wavy pattern (second problem) to change a bit, but I get the same wavy pattern on the other monitor, so it isn't the monitor itself.

And, to reiterate, I'm only having one issue on one card and one issue on another card. Both are TNT2 M64. One is a PNY AGP card, the other is an nvidia OEM PCI card. I can test 50 other cards on this same setup and they won't do this. I don't really care about the M64 cards themselves really, but once in a great while I will see these one of these problems on other cards, and I made this thread hoping to figure out the cause.

I admittedly test a LOT of cards, so maybe this isn't that common, but I have experienced it on enough cards to want to know if it's fixable.

Wow, not expecting that bad.

Any chance that you have photos of the cards of interest that caused smearing?

Cheers,