VOGONS


First post, by NScaleTransitModels

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After extensive searching on Ebay, I managed to score a ATI Mach32 VLB with 2mb DRAM, model # EXM229:

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I was excited to throw it into my 486DX2-66 VLB system (PCChips M601), thinking it would be a huge upgrade over the atrocious TVGA9200CXR. As soon as I powered it up, I noticed that the text became "chunky" all of a sudden, like the Mach32 was operating in CGA mode. Here's what the BIOS screen now looks like:

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Here's what the same screen should look like, with a GD5429 ISA:

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At first I thought that was just the way the Mach32 displayed text, but Windows 95 won't boot AT ALL. Not even in safe mode. It locks up the computer within seconds of hitting the boot splash. What's even weirder is that when I tried reinstalling Win95, the reinstall went fine and there were no issues with the first boot. The desktop loaded fine with no graphical glitches. I did some quick playback testing (more on that below) and rebooted; it went back to the same issue with Win95 hanging up on the splash. I don't have any of these issues with the GD5429 ISA.

After some more searching, I found that there is a Mach32 utility, INSTALL.EXE, that can set the video mode when booting up. Thinking that my card was set to CGA mode or something, I ran it but didn't see anything out of the ordinary:

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Does anyone know what could be wrong with my Mach32 and why it's displaying weird text, or why it hangs up Win95? If I have a bad card, it is not too late to reach out to the Ebay seller. It was tested according to him (to what extent IDK) and has warranty.

As a side note, video playback on this machine seems very sluggish as well. A 180p Cinepak AVI plays fine at 640x480x8bpp on my 386DX-40 rig, and just about plays at 640x480x16bpp. Yet on the 486DX2-66, it won't smoothly play the same file at the same settings w/ the same GD5429 ISA and just barely manages on the Mach32. (the only time I got it to boot) This leads me to believe something's iffy w/ my setup but don't have another working VLB system to test. Also DOS benchmarks look fine, eg. Topbench of 123 on the 486 even w/ GD5429. What gives, how could a 386DX-40/ ISA beat a 486DX2-66/ VLB for video playback?

Builds:

  • ECS FX-3000; 386DX-40@50; ET4000AX, ISA 1mb
  • Acer VI9; 486DLC-40; Mach32, VLB 2mb
  • Chicony CH-471A; CX486s-40; Mach32, VLB 2mb
  • Gateway 2000 P5-60; Pentium-60@66; S3 928, PCI 3mb
  • DTK PKM-0033S; AM5x86-133@160

Reply 1 of 5, by the3dfxdude

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NScaleTransitModels wrote on 2021-04-13, 19:45:

After some more searching, I found that there is a Mach32 utility, INSTALL.EXE, that can set the video mode when booting up. Thinking that my card was set to CGA mode or something, I ran it but didn't see anything out of the ordinary:
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The screen says VGA Memory Size : 256kb

Is the VGA ROM loading at power on?

Reply 2 of 5, by Thandor

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Weird stuff! Although I do like the text-mode of a CGA setup, eventually you want VGA 😉.

I notice that you have 3 jumpers for IRQ-settings. Please double check but I think one should be connected to provide an IRQ for your card. (Edit: looking on-line I see various configurations. Some have no jumpers at all, some have even 2 connected!)

thandor.net - hardware
And the rest of us would be carousing the aisles, stuffing baloney.

Reply 3 of 5, by NScaleTransitModels

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I figured it out!

Changing the VGA Memory Size didn't make a difference, and the power-on screen looked normal with the "ATI MACH32 VLB" string displayed.

But it turns out there were video mode options that I missed in INSTALL.EXE. I first thought that changing from VGA mode to CGA mode and back might correct the EEPROM or something. But upon selecting VGA mode again, I was presented with two different Color VGA modes, VGA (CV80) and VGA (C80). It had previously been set to the second option, but choosing the first option fixed the text mode and also allowed Windows 95 to boot up!

My only guess is that this card was set to a more conservative text mode, to be tested and installed by an OEM. But it was never installed by said OEM!

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Thanks for the responses! Also, here is the site with info and INSTALL.EXE for anyone who may need it: https://www.ardent-tool.com/video/ATI_Graphic … _Ultra_Pro.html

Builds:

  • ECS FX-3000; 386DX-40@50; ET4000AX, ISA 1mb
  • Acer VI9; 486DLC-40; Mach32, VLB 2mb
  • Chicony CH-471A; CX486s-40; Mach32, VLB 2mb
  • Gateway 2000 P5-60; Pentium-60@66; S3 928, PCI 3mb
  • DTK PKM-0033S; AM5x86-133@160

Reply 4 of 5, by the3dfxdude

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I think it's more likely a corrupted EEPROM causing it to fall back to CGA. I've had a corrupted EEPROM on one card before, I had to go back through all the PNP settings to fix incorrect behavior. I don't think they would have shipped a SVGA card, and had to provide OEM instructions to make sure the installer configured the card first to run graphical programs on boot because it's shipped to boot in CGA emulation mode. If someone has the install instructions, maybe it will be clear then.

Edit: The page you shared hinted that a factory default setting should have allow booting to Win95 at least. Not sure why resolution support is not auto detected. Maybe because extra RAM sockets?

Reply 5 of 5, by megatron-uk

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I've had similar on a 3Com card before - the onboard serial eeprom was corrupt and if you tried to load a packet driver or anything, it just wouldn't work. After running the setup utility, loading the defaults and writing them back fixed it.

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