I have the very same card and I remember having the same issues, it was a pain in the a. to get the card running. As far as I remember it is a non PNP card and you need to install the win95 .vxd driver manually. (Control panel / Hardware / search for non PNP hardware / select chose driver destination manually. Maybe you also need to manually adjust the adress/IRQ/DMA settings in the hardware details.
Depending on your Mainboard it could help to go into the Bios and let the Bios manage resources instead of PNP OS, and reserve the IRQ 5/7 to legacy ISA.
Regarding to DOS, did you get adlib sound out of it and did you check the mixer settings? Maybe the card is speed sensitive in dos, did you try it after disabling the 1st and/or 2nd level cache in the Bios? If you have another ISA slot, maybe try this as well. The card is very beautiful with it's blue PCB and board design/placement of the components is art. Good luck and don't give up👍

Maybe you can send a Picture of the Card itself.

If you have the Same Issues like me, then all Capacitors started leaking.
Powering the Card will Speed up the Destruction.

All small Aluminium Caps should be replaced and it should be cleaned carefully.

Its still pain in the ass to setup the Card 😁
It has some compatibility issues too

I marked the missing capacitors with red. I soldered them. The capacitor in the audio section (smaller) is twisted because I had to solder directly to the grommet - the pads were broken. I think I did it correctly. Just in case, I marked in yellow the place that looks like the laminate is detaching from the PCB - it's just an e-cigarette liquid: v

Besides, the card looks fine. I've also replaced the ide slot in it, but that shouldn't affect how it works

I have already tried to reserve irq and dma in bios, I tried to slow down the processor and disable the cache - no results. Yesterday I also tried to connect the card to another board (ga-7zx) - same results.

Replacing all capacitors is of course pain in the a **, so maybe in the first place someone would be able to determine which capacitors are responsible for powering individual circuits, and which for the audio path.

https://github.com/JKnipperts/OPTi82c929_Driver
You can also try the Alternate Driver from Jan Knipperts.

Well it could be two Issues, you try to run in very modern Motherboard.
Maybe the Card is speedsensitive, or the System is not fully ISA Conform.
I would first try get it work in a Period Correct Mainboard.
Maybe 486 or P1.

If it still does not work, it could be the Caps.
Caps can go Bad without being visible.

TLDW; the reason was the bad solder joint between the OPTI chip and the PCB.

TLDW2; i fried opti chip with hot air and i need the substitute. Can i use 82c931 instead of 82c929A?

These chips are not pin compatible, you need 929 to revive the card.