Do you use any SD to IDE adapters or similar modern storage solutions?
I've had very weird issues with some of these adapters when using certain combinations of hardware (audio crackling/popping, screen artifacts and/or strange colors, etc)

bloodem wrote on 2025-01-07, 18:37:

Do you use any SD to IDE adapters or similar modern storage solutions?

This is all vintage hardware 😉

I have also tried:
- 3 different BIOS versions (05/06/1996, 10/16/1996, 09/15/1998)
- different Cache settings for L1 and L2 (WB / WT / disabled)

I'd guess you have an IRQ / DMA conflict? I've never seen the exact color corruption you are dealing with, but I had a system where the audio card was conflicting with the onboard IDE controller and as soon as Wolf3D played a digitized sound it would crash. Ultimately I reconfigured the audio to use a non-standard IRQ/DMA. Since you already tried changing the sound card, maybe try changing another device. I think some BIOS's optionally let you assign the VGA card an IRQ.

BinaryDemon wrote on 2025-01-08, 21:13:

Since you already tried changing the sound card, maybe try changing another device. I think some BIOS's optionally let you assign the VGA card an IRQ.

Which other device do you think I should try? I plan to test a few more VLB graphics cards.
I have not found a function in the BIOS of the M919 to assign an IRQ to the VGA card. But I also know this option from other systems.

Looks about right. This was my M919 experience with a VLB Speedstar a 1996 ago so I went with a PCI Trio64V+ instead. I think the problem was on the clock (mine was set to 40x3 at the time) but I had no palette issues (or burnt out cards (!!!!)) from the PCI and ISA slots.

I have found the M919 with VLB graphics and ISA sound particularly problematic. The best working combination I found was:

ISA sound: YMF-719E
VLB graphics: ARK1000VL

I think a Diamond Stealth 32 (ET4000/w32p) may have also worked.

I have now been able to test more VLB graphics cards.

CL-GD5424
CL-GD5426
ALG2228

There were no graphics issues with these, but there were sound artifacts in the games that had graphics errors with the other two cards.
Some of the sound artifacts were quite massive. The level of heaviness depends on the game title if it uses digital sound from the sound card. But it also depends on the VLB graphics card used.

The sound artifacts occur when:

- loading / initializing the game
- loading the title screen / fading in and out
- before or after video sequences
- selected resolution of the graphics in the game

I was able to reproduce the errors 1:1 with the individual VLB graphics cards on a second M919 board.

Many of the sound artifacts were least significant with the ALG2228 card. (AVANCE LOGIC ALG2228 FCC ID: JQDA2228AV9401)
The Cirrus Logic cards behaved very similarly.

There really seems to be a general problem with the VLB implementation of the M919.

Did you try and move the sound card to different ISA slots (i.e.: as far away from the VLB slot as possible)?
As weird as it sounds, this worked for me in the past on one of 486 builds.

Edit: ugh, this might not be possible with the M919, because of the very bad layout (CPU heatsink is probably in the way).

919guy wrote on 2025-01-12, 16:41:

There were no graphics issues with these, but there were sound artifacts in the games that had graphics errors with the other two cards.
Some of the sound artifacts were quite massive.

Which games? I tested primary with DOOM and the sound distortion went away with the YMF-719. My particular sound card had two oscillators. Like you, I also had to test several VLB graphics cards.

Doom and other games produce the graphics failures (wrong color palette) shown above with the CL-GD5428 and the Trident VL46A/V2.
With the other cards I have tested you only hear a short pop/crack when starting and closing doom. Furthermore, the sound didn't seem quite clean in some places with the Cirrus Logic cards.
I tested with Formosa SC1616 ESS688FC OPL3 (KWX-SC1616) and Terratec 16/96 Gold (ESS AudioDrive ES1868F).

In Blood, the title screens are displayed at the beginning. There are sound artifacts during the fade-in and fade-out. These are much less noticeable with the ALG2228 than with the Cirrus Logic cards.

I should still have a Labway YMF719E-S (LWHA151A00) sound card. Perhaps I can test again with this to see if there are any differences.

919guy wrote on 2025-01-13, 22:27:

Doom and other games produce the graphics failures (wrong color palette) shown above with the CL-GD5428 and the Trident VL46A/V2.
With the other cards I have tested you only hear a short pop/crack when starting and closing doom.

Yup, that's the same thing I witnessed. Once I found a suitable VLB graphics card which didn't exhibit graphical glitches, I had to find the right sound card. I also was trying to force ESS cards to no success. Try out your Labway. It worked for me.