Is this an earlier revision Diamond Monster 3D? They seem to have some design issue that causes diagonal scrolling lines on some TFT monitors. There are some suggestions what to do here: Diamond Voodoo 1, bad passthrough video quality

Doornkaat wrote on 2022-02-27, 03:45:

Is this an earlier revision Diamond Monster 3D? They seem to have some design issue that causes diagonal scrolling lines on some TFT monitors. There are some suggestions what to do here: Diamond Voodoo 1, bad passthrough video quality

Oh crap, so it's a manufacturing defect? There's a spot for the revision to be printed on the card, but it's blank. I'm guessing it's a revision B.

One of the solutions in that thread is to use a VGA switcher? I'm not sure how that will help, since I get these lines even when I take out the passthrough cable.

The other solution is the filter mod which is above my skill level.

I can't say for sure what the general issue with (some?) earlier Diamond Monster 3D cards is, just that those scrolling lines seem to be characteristic for them.
My assumption is it is not a defect but a consequence of sloppy design. It didn't matter much back when the cards were new because at least the problems I have observed are not visible on CRTs. It is probably some degree of incompatibility between the Voodoo and the scaler in the TFT so the issue may vary depending on the monitor you're using.

The VGA switcher is suggested when the issue is with the 2D image. It would not help in your case, you're 100% right there.

I wish I could tell you something more useful but in my opinion it is a general issue with this card model that takes hardware modifications to fix.

Doornkaat wrote on 2022-02-27, 07:25:

I wish I could tell you something more useful but in my opinion it is a general issue with this card model that takes hardware modifications to fix.

Would an external VGA booster help?

I have an early Revision of that card and have the same issues.

The diagonal lines is a noise that gotten into the video signal on the card. You need to modify the card through.

I had herringbone lines in the captured video of a capture card and for some dumb reason the tracks was not designed correctly and long way to the chipset from the connector. So I modified it by ripping out the tracks and installed coax cables and terminated them correctly. No more herringbone.

Cheers,

pentiumspeed wrote on 2022-02-27, 17:37:

The diagonal lines is a noise that gotten into the video signal on the card. You need to modify the card through.
Cheers,

Yes, but what if @Doornkaat is right and it is due to some incompatibility between the Voodoo and the scaler in the TFT, then if I can eliminate the incompatibility I can eliminate the noise in the signal. I was thinking of something like this: https://www.extron.com/product/p2da2xib

It has controls for output gain, as well as input and output impedance syncing. Could that eliminate the incompatibility?

I never noticed the same sweeping lines on my Voodoo2 until I tried it on a TFT decades later. Went back to a CRT to do my research...

I don't have my Diamond Voodoo 1 any more. Sold it a year or two back. My memory of it, is that those diagonal lines were also faintly visible with a CRT, however they were much more noticeable with an LCD.

I always assumed the difference was part of the general tendency of LCDs being harsh and unforgiving with old analog content that was meant for CRT.

enaiel wrote on 2022-02-27, 17:26:

Doornkaat wrote on 2022-02-27, 07:25:

I wish I could tell you something more useful but in my opinion it is a general issue with this card model that takes hardware modifications to fix.

Would an external VGA booster help?

I don't think so but I'm not very knowledgeable about analog signals. If the interference is filtered by the booster it may help but I would not count on it.

enaiel wrote on 2022-02-27, 17:50:

pentiumspeed wrote on 2022-02-27, 17:37:

The diagonal lines is a noise that gotten into the video signal on the card. You need to modify the card through.
Cheers,

Yes, but what if @Doornkaat is right and it is due to some incompatibility between the Voodoo and the scaler in the TFT, then if I can eliminate the incompatibility I can eliminate the noise in the signal. I was thinking of something like this: https://www.extron.com/product/p2da2xib

It has controls for output gain, as well as input and output impedance syncing. Could that eliminate the incompatibility?

I'm with pentiumspeed here. You probably need to prevent the noise from getting into the output signal in the first place.
I'm sorry if there was a misunderstanding because I can't express myself precisely: There is not a general incompatibility between your screen and the card. I just assume that some TFTs are better at handling noise in signals than others. That would make some screens better suited for the noisy signal coming from your card.

Doornkaat wrote on 2022-02-28, 07:10:

I'm with pentiumspeed here. You probably need to prevent the noise from getting into the output signal in the first place.
I'm sorry if there was a misunderstanding because I can't express myself precisely: There is not a general incompatibility between your screen and the card. I just assume that some TFTs are better at handling noise in signals than others. That would make some screens better suited for the noisy signal coming from your card.

Ah, got it. I did notice that the lines decreased in intensity when passed through a scanline generator circuit even when it was disabled. I guess it was just filtering out some of the noise.

Voodoo 1/2 DACs are noisy, yep.

I just wanted to report that the VGA booster made a massive improvement to the image quality of the Voodoo 1.

The lines are not totally gone, but they no longer annoy me. Well worth $10!

I am not sure if the above gif files are accurately conveying what it looks like in real life. All I can say is that the second pic does not look good to me. Yes the diagonal lines are gone. But instead there is a whole lot of other ugly flickering and distortions constantly ripping down the image. I hope those are not present in real life, for the sake of your eyeballs!

Shreddoc wrote on 2022-03-02, 20:35:

I am not sure if the above gif files are accurately conveying what it looks like in real life. All I can say is that the second pic does not look good to me. Yes the diagonal lines are gone. But instead there is a whole lot of other ugly flickering and distortions constantly ripping down the image. I hope those are not present in real life, for the sake of your eyeballs!

The flickering and distortions are probably because I was holding the device in my hand with all connections loosely connected 🤣. Here's a better GIF:

Hey, nice! Good to know there's a bit of a workaround.😃👍

enaiel wrote on 2022-03-02, 20:52:

Shreddoc wrote on 2022-03-02, 20:35:

I am not sure if the above gif files are accurately conveying what it looks like in real life. All I can say is that the second pic does not look good to me. Yes the diagonal lines are gone. But instead there is a whole lot of other ugly flickering and distortions constantly ripping down the image. I hope those are not present in real life, for the sake of your eyeballs!

The flickering and distortions are probably because I was holding the device in my hand with all connections loosely connected 🤣. Here's a better GIF:

tomb3dem3-small.gif

Awesome, good result.

Doornkaat wrote on 2022-03-02, 21:13:

Hey, nice! Good to know there's a bit of a workaround.😃👍

Shreddoc wrote on 2022-03-02, 21:27:

Awesome, good result.

Thanks, just want to point out that it's not the VGA boost function that is actually reducing the noise. The boost function, and the input and output impedance matching merely seem to make the dim Voodoo1 signal brighter. I'm guessing it's probably got noise reduction circuitry built in since it's designed to connect desktops and laptops with a projector connected by over 75m of cable, and that's what's doing the trick.