That's interesting, and a it unexpected to be honest.

The breakout box shouldn't help you with getting these games to work, as the actual MPU401 interface is on the LAPC-I card already. The breakout box just supplies connections for an external module.

Also games shouldn't sound wrong. Only certain sounds might sound a bit off, but this is something you need to look for, it's not something that is obvious or really stands out.

They definitely shouldn't sound "funny".

I also have a MPU401 ISA card (midi man MM401 and MPU401AT) and just use a MT-32 (old) and CM-32L. With these modules you have all your bases covered.

Although you haven't asked for advice, I would recommend selling the LAPC-I and sourcing a CM-32L. That way you have all bases covered, be it with real vintage hardware or vis DOSBox and USB Midi adapter.

The game I was mostly referring to when I said games sounded funny was King's Quest V. I think the strange sounds I hear are ambient sound effects that fail to upload to the RAM of later version MT-32 and LAPC and are instead replaced with instrumental sounds. The most notable of these is the sound of water dripping from the Weeping Willow.

I was mostly wondering if any LAPC-I owner could confirm my observations so I know if my LAPC-I is dysfunctional or not.

I will look around for a CM-32L or similar, but I think I'll keep the LAPC-I just in case. After all, it took me years to find it.

Could there be a resouce conflict? Did you run these games in pure DOS or Win98?

I'm using pure DOS and it seems like there was a resource conflict, even if I'm not quite sure I understand it. Apparently at least my LAPC-I uses not only IRQ2, but also IRQ3 for something that is necessary to run Eric the Unready and Gateway. If I let another sound card or a serial mouse use IRQ3, I would get the error I mentioned in my first post. With IRQ3 available, I can play those games with music, which shows that the LAPC-I is indeed 100% MPU-401 compatible. Interestingly enough, I can make the LAPC-I conflict with itself by jumpering it to IRQ3 instead of IRQ2.

Martian Memorandum still doesn't work though, no matter what I do.

My question this time is if everyone else's LAPC-I also use IRQ3 and if this can be disabled somehow so only IRQ2 is used?

Do you have an conflict with IRQ2? A video, NIC or SCSI card perhaps? Poor IRQ cascading on your motherboard? What speed/type of system are you trying to run MM on?

I'm using a socket 7 Pentium 200 MMX. I've tried to remove or disable everything non-essential, but IRQ3 is still hogged by the LAPC-I. I've also tried to jumper the LAPC-I to use other IRQ:s than the default 2, but Eric the Unready won't recognize the card when jumpered to any other IRQ than 2. For instance, if I jumper the card to IRQ 5 and start the game by typing "ERIC MT32 5 330", then I get the "Unable to access the MT32 on IRQ channel 5" error message.

Problem solved! I seem to have misunderstood the jumpering system. I assumed that J02 would be IRQ2, J03 would be IRQ3 etc, and that the J01 that comes after J06 was a misprinted J07. But now I realize that the card was jumpered to use IRQ3 all the time, since J02 was closed. Now I have closed the J01 and the card only uses IRQ2 as it's supposed to do. Why I could still use IRQ2 when the card was jumpered to IRQ3 I don't know, but it doesn't matter now.

Did this also solve the problem with Martian Memorandum? It wouldn't play nice with my LAPC-I either, but I assumed that it was an issue with the speed of my CPU and timing issues.

I installed the LAPC-I in a 486DX4/100 to try Martian Memorandum in a slower computer than the Pentium MMX I was using before. I get music in the game if I push the turbo button to de-clock the processor to 16 MHz.

I've got the same cpu running. No turbo buton on my chassi but i'll give turning the cache off a try and see if that helps matters.