Nice one!

Thanks! I hope it helps out others.

nice rescue! thanks for the info!

Interesting. I have similar problem which only occurs if I connect pass-through cable.

Those are some really interesting insights into how the card works and how to troubleshoot these cards when things aren't working right, thanks.
Nice clean work replacing the RAMDAC too 😀

The Serpent Rider wrote on 2020-03-15, 10:35:

Interesting. I have similar problem which only occurs if I connect pass-through cable.

That could be just the PI5c3384 gone bad or the pass-through cable shorting out somewhere etc.
My pass-through cable from China for example isn't made in a very quality controlled environment.
The cable I ordered first has a contact issue, turning the screen yellow when I poke it.
At least it was cheap!

That output switching IC is just working like a switch. Picture 4+4 MOSFETs switched by two enable signals.
If one of those internal switches catch electrostatic discharge, they can fail.
Does your main non-3DFx video card work okay hooked up just by itself?

Thermalwrong wrote on 2020-03-15, 10:59:

Those are some really interesting insights into how the card works and how to troubleshoot these cards when things aren't working right, thanks.
Nice clean work replacing the RAMDAC too 😀

Thanks! 😁 My pleasure!

V2s have very noisy video output - I wonder if there a is a pin-compatible DAC which would yield better output?

maxtherabbit wrote on 2020-03-15, 14:14:

V2s have very noisy video output - I wonder if there a is a pin-compatible DAC which would yield better output?

Not sure. The other question is: are they still available like the ICS? The ICS has an RSET pin to set DAC output levels on each channel by resistors to GND. Like one would have it on an RGB LED controller's sink current setup. In theory levels can be raised even further. If that S3 card outputs 1.5V this should cause no harm. Well at least for the monitor itself. I've seen some cards on the net using a Texas RAMDAC. Seems pin compatible enough. Maybe it was just TI acquiring ICS GENDAC. I'm not very good at RAMDACs, but if someone could mimic the behaviour of these DACs with like a CPLD plus a modern RAMDAC it could be possible. Put it on a castellated PCB and done, pin compatible. When it comes to manufacturing of course 4+ layers are not cheap for a small,but complex PCB.

Also the noisy output has to do with the long signal path involving an active component (selector IC) in it too. It looks odd now, but this blending filtering 3DFx used on the small scale pixelated textures of that time, to be smooth was quite useful. Nowadays it's all about fast AND crisp output. Times sure have changed.

christal87 wrote on 2020-03-15, 13:50:

That could be just the PI5c3384 gone bad or the pass-through cable shorting out somewhere etc.

That's not ordinary Voodoo 2. It's Canopus 3D card with custom cable.

The Serpent Rider wrote on 2020-03-15, 16:47:

christal87 wrote on 2020-03-15, 13:50:

That could be just the PI5c3384 gone bad or the pass-through cable shorting out somewhere etc.

That's not ordinary Voodoo 2. It's Canopus 3D card with custom cable.

It looks basically the same, except for the additional Scalable VGA to NTSC/PAL Encoder. It has a similar QS3L384QG output selector IC. Some other cards use it too. The only other big difference is: it has only one DSUB connector. The other one is routed to an IDC connector from the selector IC to hook it up to other cards supporting it or hack a DSUB connector to it on an empty, separate PCI slot cover. So it's basically mixing/switching VGA signals with other supported cards. I have read a few minutes ago that they called it a WitchDoctor config. Interesting! I've never seen it before. We learn something new (old) every day. 😀

I was going to ask this question separately, but now there's a thread for it...

I have a S3 Savage4 passing through a voodoo2 SLI combo, and sometimes the color comes out green. In DOS the text will be green, and when playing a games, the colors have been green-washed but still distinguishable.

Before I pull apart this whole system, where is the problem likely to occur...the Savage4, the V2s, or the passthrough cable?

kolderman wrote on 2020-03-15, 18:33:

I was going to ask this question separately, but now there's a thread for it...

I have a S3 Savage4 passing through a voodoo2 SLI combo, and sometimes the color comes out green. In DOS the text will be green, and when playing a games, the colors have been green-washed but still distinguishable.

Before I pull apart this whole system, where is the problem likely to occur...the Savage4, the V2s, or the passthrough cable?

you can very easily narrow that down by just removing the pass through cable from the equation and plugging the monitor directly into the S3 or directly into the V2 (while it is active of course)
the pass through cable is not required for the voodoo to function

kolderman wrote on 2020-03-15, 18:33:

I was going to ask this question separately, but now there's a thread for it...

I have a S3 Savage4 passing through a voodoo2 SLI combo, and sometimes the color comes out green. In DOS the text will be green, and when playing a games, the colors have been green-washed but still distinguishable.

Before I pull apart this whole system, where is the problem likely to occur...the Savage4, the V2s, or the passthrough cable?

If your simple DOS command prompt is also green, as you say, then there could be a contact issue involving all these in the signal path:

• your S3 card's DSUB connector and/or
• pass-through cable and/or
• voodoo2 DSUBs and/or
• monitor cable and/or
• could be the output selector IC.

Try fiddling around with the cables to see if it's intermittent. My issue was constant and limited to glide usage (gameplay).

It's very intermittent. As in it flashes while playing a game between green-shaded to normal. I will try and take the V2SLI out of the equation first and see what effect that has.

kolderman wrote on 2020-03-15, 20:15:

It's very intermittent. As in it flashes while playing a game between green-shaded to normal. I will try and take the V2SLI out of the equation first and see what effect that has.

I think the SLI has nothing to do with it, because it doesn't pass any analog video signals between cards. The card I repaired was used as a slave card before. It didn't have the color issue that way. It's the DSUB connectors and cables you should check.