Recap and/or replace YAC512 DAC IC, assuming there is no other obvious damage. One of the 3403 op-amps (not sure which one) might be faulty as well.
In any case it can be saved.

Is there any visible problems/damage to the card? Do all the caps look okay, no bulging ones, none have got a loose leg or anything like that?

If there are no obvious visible issues and the card is only semi-working, then a recap could be worth a try. Failing that it might just be one of the chips is on it's way out unfortunately

tp1020 wrote on 2020-07-30, 20:28:

I have a CT1600 SBP2, and it has been working fine for some time but earlier today I noticed there was no music in certain games. I eventually discovered that digital audio worked fine, but everything to do with the FM chip seems to be broken. As an example I can hear the gunshots and "halt!" voice clips in Wolfenstein 3d just fine but there is no music or sound when I pick up items. When I tried playing a midi file i could hear very faint and distorted sound when the volume was boosted to the max.
Anyway, could a recap fix this problem? anything else I could try?

Disable the mic in configuration. Or just turn it off.

Intel486dx33 wrote on 2020-08-03, 21:40:

Disable the mic in configuration. Or just turn it off.

Is there a way to do this apart from lowering the volume in the mixer?

Anyway, the reason I'm looking at this again is not because I fixed it but I was able to try it on another motherboard in case that was the issue. It was not.

Here is a video showing the problem, the speaker is at max volume and you can barely hear the music:

https://youtu.be/-Cis_hzHaDc

Hey I recently had a very very similar issue with my strange soundblaster clone card, it could make digital audio but FM audio was near silent. That turned out to be a faulty FM DAC, which was fixed when I replaced the 'SC802' with a regular YM3014.
Here's my experience with it: Re: Anchor Electronics - Media Concept 2.0 Souncard - SB 2.0 clone with real OPL2

You should be able to fix your card by swapping out the YAC512 at U20. Buuut, since the SB Pro 2 has a more standard OP-AMP configuration, you may also want to check/swap out the LM3403 OP-AMP at U12 if that doesn't resolve it.