I know this is a really old thread, but i just had to add that i had a similar problem, but rather than starting a new thread, i thought i could just add to this one.

Wave effects worked fine, but no output from midi music whatsoever from a ct3900.
Turned out to be a shitty PSU. Bought a "450w" psu on ebay to have some wattage overhead, but it started working again when i switched back to the 230w psu that came with the case. I'm at a loss as to why one works but the other doesn't. Still, i would like to buy a more powerful psu since i'm filling up most of the pci/isa slots and stuff, but i really don't know what to pick. Anyone here who knows better what to pick? Or should i just leave it?

Specs:
Zida 4dps motherboard + AMD 5x86 @ 133mhz
ATI Rage 2+ DVD (PCI GPU)
ATI TV/MGP (ISA card connected to the Rage 2 with "ide" cable.)
Voodoo 1 (PCI GPU)
CT3900 (ISA sound card.) + mt32mccake (raspberry pi cm4) connected thorugh waveblaster header
DVD drive
FLoppy 3,5"
Gotek Floppy emulator

Another funny thing is the computer restarted if i gently slapped it while the 450w psu was installed. Must be a really low quality psu...

What do you guys think?

Edit: Figured it out. I'll use a modern PSU with an adapter + voltage blaster if needed. These old junk PSUs can't be trusted.