Keyboard & FM card issues

[moody]

Howdy! I recently received my PC-9821 V13 in the mail not too long ago. My FM card (APC-077A, a PC-9801-26K compatible card) came shortly after. However, the card itself does not seem to want to cooperate with this setup.

Some games will throw an error/not start. Some of the errors ask for a specific INT like 0 or 6. I can set INT0 in the BIOS menu, but not INT6 since I just have 0, 1, 41, and 5 as options.

Some games will start up, but behave strangely. For instance, Flame Zapper will launch, but not accept any keyboard input whatsoever when the card is inserted. Without the card, it behaves normally.

Other games will launch and play just fine, but without any sound at all unless they use the PC speaker for SFX.

When I inspected the board, there was a broken 100uF cap that I replaced right away, but that showed no change in behavior. Personally, I'm just kind of lost at this point. I can't seem to find any information on this sound card aside from some auction listings. I've tried pretty much all of the games with all of the possible BIOS configurations for sound settings, but I'm still stuck here.

Any insight would be appreciated.

Specs/details:
-- Model: PC-9821 V13
-- Image: Caius' HDD image v1.5
-- Sound Card: APC-077A
-- Keyboard: PC-9801U