Twin Turbo 128M8 corruption in odd pattern

[BetaC]

Posting this because I am unsure of how to even figure out a fix for this. I have this card inside my SuperMac C600, and there's back and or colored dots in a pattern all across the screen. When you increase the resolution, they appear more often, but in roughly similar places, and when you increase the color depth, they sem to mostly fade away. I am running the final driver version for Mac OS 8.1, and they appear both when using VGA, and when using the normal display out on the card via a VGA adapter.

 

[Phipli]

Perhaps a faulty VRAM chip. A lose pin if you're lucky, or a bad chip if not.

Get a plastic pen with a plastic lid so no metal shows and tap on each VRAM chip one at a time while it is running to see if the issue changes at all.

 

[cheesestraws]

Agreed: looks like dodgy VRAM to me.

 

[macuserman]

I might be way off in left field here, but the few cards I've run into so far that had artifacts of various kinds were "cured" by either an eraser scrub on the PCI pins or a good cleaning with contact cleaner. May not help at all, but totally worth trying if you haven't done it already.

 

[Phipli]

I might be way off in left field here, but the few cards I've run into so far that had artifacts of various kinds were "cured" by either an eraser scrub on the PCI pins or a good cleaning with contact cleaner. May not help at all, but totally worth trying if you haven't done it already.

This fault is to small to be a whole pci pin, it's going to be on a single pin on a single vram chip I suspect, or an error internally within a chip.

 

[macuserman]

This fault is to small to be a whole pci pin, it's going to be on a single pin on a single vram chip I suspect, or an error internally within a chip.

Gotcha, the errors I have fixed have been much larger whole screen grainy or stripped etc so that makes sense.

 

[BetaC]

After pressing on all sixteen or so chips, the issue didn't disappear. Strangely, it doesn't seem to show up when in millions of colors, and when in 256 grays. As this is the only mac compatible PCI card that I have, I'll just have to use internal video for now. I'm not going to sacrifice my Voodoo3 to play marathon.

 

[Byrd]

Whatever it is it looks minor, a deep clean of the case, PCI connector, PCI slots, might just fix this up. A Voodoo 3 is a great sacrifice for any PCI Mac by the way . The cooling is woeful on these cards I've put a fan on the core and heatsink on the back of the card.

 

[trag]

I had a near identical issue with an ixMicro Ult. Rez. card back when they were new and shiny. ixMicro told me the symptoms were definitely a bad VRAM chip and replaced the card for me. That issue also moved around with differing resolutions. The VRAM storage gets interleaved in different patterns depending on resolution and color depth and that effects how the flaw appears in the display.

 

[BetaC]

Whatever it is it looks minor, a deep clean of the case, PCI connector, PCI slots, might just fix this up. A Voodoo 3 is a great sacrifice for any PCI Mac by the way . The cooling is woeful on these cards I've put a fan on the core and heatsink on the back of the card.

Yeah, I have a card with the bigger heatsink already, and use a system blower underneath to keep it cooled. Given their prices, though, I'd rather have my Voodoo doing stuff like playing TES Redguard and regue squadron in GLIDE instead of a handful of mac games. I also managed to scrounge up a B&W G3's Rage 128, which is now resting inside my clone, putting up no fuss while saying it can go up to 1920x1080 on a CRT that can't.