OK, so a minor update.. Here is what the PCI/IRQ setup of the Compaq Deskpro EN looks like:
So you can set devices as IRQ 5/10/11 only and they have to shar ethe IRQs and play ball with each other - it's a matter of juggling them around until you figure out what PCI device can live peacefully with what.
The attachment Deskpro EN-SFF YMF744 01.jpg is no longer available
Anyway, I eventually managed to find a configuration where I could set the YMF744 to IRQ5 in BIOS that works:
The attachment Deskpro EN-SFF YMF744 02.jpg is no longer available
So I booted into Windows, and SETUPDS.EXE still does not allow me to alter the IRQ:
The attachment Deskpro EN-SFF YMF744 03.jpg is no longer available
But SETUPDS.EXE plays PCM audio and FM music just fine, so the card works:
https://youtu.be/7AnHhQK_TkM
Sort of. The above recording was done without the YMF TSR loaded. When I load the TSR at boot (or prior to running SETUPDS.EXE) which also requires EMM386.EXE to be loaded, SETUPDS.EXE locks up the computer when run.
Regardless, the card works completely fine in Doom, Dune and Monkey Island 2. Fantastic OPL3 music and crystal clear PCM.
Strangely enough, when I load DUNE II in pure DOS, the intro audio STILL cuts off after "Planet Arraki-...." and the game still locks up after selecting a house after the "House Atreides" digital speech - the Mentat screen never comes up but the OPL3 music keeps playing..
All I can think of at this point is that the 1GHz Pentium III in the system is just way too fast for a game like Dune 2 to run?
