Beiträge von Justin1091

So I did have a look at the bios editor, did not find a way to disable guardband clipping. Anyone know why it could freeze with it enabled? I'm currently looking at the power section of the card (near the molex connector). Maybe the setting causes a spike or decrease or whatever in power and it then freezes. I'm just thinking out loud here, more suggestions are appreciated!

I did replace a bad resistor today and the card's power before conversion to 3.3v went from 2.8v to 2.6v. Still the same problem. I don't understand why the good card goes from 3.0v to 3.3v. I also noticed that both cards have different resistors on them (values). Maybe someone can upload a photograph of their voodoo5 showing some resistors?

U1 = CMD (California Micro Devices) PACVGA105Q = VGA Port Companion Circuit

U4 = NJA = TPS3801J25DCK 2.25 V ULTRA-SMALL SUPPLY VOLTAGE SUPERVISORS <-- not sure

U6 = Fairchild VCX08 (74VCX08) = Logic Gates Quad 2-Input AND Gate

U7 = IDT QS3861Q = CMOS 10-BIT BUS Switch

U8 = Atmel AT49BV512-12JC = NOR Flash 512k (64kx8)

U12 = LTC1929CG = 2-Phase Synchronous Step-Down Switching Regulator (MOSFET Controller)

U13 = BMS = ??

AR1 = National Semiconductor LM358M = Dual Op Amp

Q1, Q2, Q3, Q4= IR IRF7811A = MOSFET N-CH 28V 11.4A 8-SOIC

Q5 = IR LR2703 = MOSFET 30V 1 N-CH HEXFET

No idea if you're still active or updating your post It's a really nice list though. Would be awesome to see it 100% complete. Found out about these parts while working with someone over at vogons

Thanks guys, I'll have a look. However I still believe it's a hardware issue that can be fixed. Since I now have quite a bit of time and I enjoy diagnosing and fixing hardware, editing the bios is a step I will take when I'm sure there is nothing more I can do.

When I have time I'll try different modes (glide, d3d) with guardband clipping off to be 100% sure. Yesterday I found that 3dmark99 ran with both chips and guardband disabled.

Might be a good idea to disable it in the bios and then running tests. Didnt even know thats possible. Thanks!

Thank you, the capacitor on the picture is wrong. It is now replaced with a correct one.

Yeah I could disable gbc. But I'm not 100% sure that is the problem, 99% but still :). Also, it would be cool to fix it as it is clearly not working properly (I need vcontrol to disable gbc. Reference 3dfx driver doesn't work because it locks up.) I'l probably have another look with a magnifier yeah.

Hello,

I have a voodoo5 which crashes when running in dual chip mode in game. The problem occurs when 'guardband clipping' is enabled in the driver. (99% sure this is the problem). I have another working voodoo5 which does not have this problem. Both cards have the same 3d Mark score in 3dmark99 with both chips enabled, so I think the vsa100 chips are good.

I have been working with someone over at vogons.org trying to fix this problem. All the card's caps have been replaced but this didn' work. Different BIOS also did not work.

Maybe it has something to do with the card's power. Both cards run at 3.3v but the non working card goes from 3.0v to 3.3 while the good card goes from 2.8v to 3.3v. Anyway, that's all I have found out (aside from some resistance checks with the test points on the pcb).

I'm still working with the person over at vogons, maybe someone from this board knows of this problem or someone has a suggestion/tip.

Thanks! Hope English is ok, I'm Dutch and my German isn't much good.

https://www.vogons.org/viewtopic.php?…da4ac37b0377da0