Most of the C/MS upgrade kits support only the older CT1336 bus interface chip. If your card happens to have the newer CT1336A on board, both the original and cloned upgrade kits won't work properly and will interfere with the FM synthesis.

What is your exact CT1350B board revision?
Take a look here: http://nerdlypleasures.blogspot.com/2013/06/t … ms-upgrade.html

My card appears to have an revision number of 060328, and have the CT1336A bus logic chips, which does mostly explain why most programs don't seem to detect the card with C/MS enabled, but that still doesn't explain why other programs (like DIAGNOSE.EXE, FastTracker 2, Inertia Player, and SBVGM) can use the FM and DAC chips just fine, and SBVGM can even use both the FM and C/MS at the same time!

P.S. here's the image of my card in question:

Yes, that's exactly the problem. The GAL is not compatible with CT1336A.
I reverse-engineered the differences between CT1336 and CT1336A and wrote a new set of GAL equations compatible with both of them. Selling this kit on eBay right now. 😀

I may list just the GAL there, if you are interested.

I'll order one when I can. Thanks! 😀

I just listed the GAL (/itm/283355371046). The compatibility with CT1336A is explicitly mentioned in the item's description. You're welcome to make me an offer (mention Vogons).

suntac wrote:

Yes, that's exactly the problem. The GAL is not compatible with CT1336A.
I reverse-engineered the differences between CT1336 and CT1336A and wrote a new set of GAL equations compatible with both of them. Selling this kit on eBay right now. 😀

I wonder if it'd be possible to cobble together a CMS add-on for a Soundblaster Pro 1 or 2, since they use the CT1366 or CT1366A. It'd have to be in the form of a daughterboard I guess... anyway, just thinking out loud. 🤣

Ozzuneoj wrote:

I wonder if it'd be possible to cobble together a CMS add-on for a Soundblaster Pro 1 or 2, since they use the CT1366 or CT1366A. It'd have to be in the form of a daughterboard I guess... anyway, just thinking out loud. 🤣

Theoretically yes, but cutting PCB traces and/or desoldering ICs would be involved.
You would also have to place a switch somewhere which would then be used to choose between C/MS and stereo-FM synthesis as their I/O spaces overlap.

Ozzuneoj wrote:

I wonder if it'd be possible to cobble together a CMS add-on for a Soundblaster Pro 1 or 2

How about just using a Game Blaster clone next to the SB Pro?
See here: MUS-1099 GameBlaster Sound Card
My 286 runs like that. Note that both card's can't be on the same base address (unlike a regular SB 1.x or 2.0, the dual OPL2 or OPL3 is in the same address range as the SAA1099 chis), so I run the Game Blaster on 210h and the SB Pro on 220h.

Scali wrote:

How about just using a Game Blaster clone next to the SB Pro?
See here: MUS-1099 GameBlaster Sound Card
My 286 runs like that. Note that both card's can't be on the same base address (unlike a regular SB 1.x or 2.0, the dual OPL2 or OPL3 is in the same address range as the SAA1099 chis), so I run the Game Blaster on 210h and the SB Pro on 220h.

I thought most games require C/MS to be located at 220h regardless of the GameBlaster's auto-detection feature, but maybe I am mistaken.
Anyway, I somehow started to like the ISA PnP. I can design a PnP GameBlaster, a PnP SB Pro, etc. and be able to assign them various configurations on-the-fly from the DOS command prompt.

suntac wrote:

I thought most games require C/MS to be located at 220h regardless of the GameBlaster's auto-detection feature, but maybe I am mistaken.

Yea, but carlostex has a project with patches for these games. I've helped patch a few games myself (and uncover undocumented commandline arguments to specify base address in some cases).

Tested today suntac's GAL chips for CMS, my CT1336A sb2.0 works fine with both opl2 and cms .Excellent work suntac!

Thanks, keropi!