Yamaha FB-01 Repairs? Not totally Amiga related...

[commodorejohn]

I would have thought it would be more complex, but I only see one or two ICs that could be responsible for the actual FM synthesis.

AFAIK, the only FM synths with an even halfway complex layout were the DX7 series, which divvied up the sound-generation responsibilities between two chips (one for envelope generators, one for the actual operators) and the requisite DACs. Past that, they pretty much made all their FM stuff as single-chip solutions (although outboard DACs were still commonly required,) which I'm sure had a lot to do with the popularity of the things in arcade boards and Japanese home computers.

As for the unit, I'd look into recapping it before you go shipping it off somewhere, since that looks to be pretty easily doable and can often be a quick fix for analog-type issues (as this sounds like.) Though on the other hand you might just try to get your money back and buy one that's actually in perfect working order.

And for the record, the PDF Mongo was trying to link is here.

[commodorejohn]

Rock on! As for the eight instruments, the FB-01 (along with some of Yamaha's other early multitimbral synths like the TX81Z) uses a rather awkward system of "performances" or "configurations," where a "performance" specifies which of the eight parts have how many voices assigned to them, which of the stereo channels they come over, and some other assorted parameters. This is all detailed in the manual, a PDF of which can be found here. It's kind of irritating and awkward, especially when its contemporary the MT-32 has such a perfectly nice, no-nonsense multitimbral mode (well, except for that thing with MIDI channel 1 being disabled by default,) but eh, it is what it is. (At least they fixed it with the introduction of the V50.) I suspect that most games probably assigned one voice to each of the first 8 MIDI channels and sequenced them separately.

[commodorejohn]

Oh, and by the way, there's a patch librarian/editor for Windows/Linux here, and one for the Amiga here. Some patches can be found here and here.

[commodorejohn]

No problem. Glad to welcome another into the wonderful world of FM synthesis