I suggested previously that a Gotek floppy emulator would probably be the easiest way to get this old Sanyo MBC-1000 booted and running again. Turns out that was even easier than I expected.
The first thing I did was reflash the Gotek with FlashFloppy to add support for more image and drive types. FlashFloppy doesn't directly support Teledisk images, but the HxC software can convert them into something both FlashFloppy and HxC can use on a Gotek. I only needed a normal 34-pin ribbon cable for the mainboard interface, and I cobbled together a USB power adapter.
And ... that was it. The computer booted right into CP/M 2.2 without any complaints.
I do still want to try developing some new hardware for this machine. Now that I have a proper operating system with BASIC and an assembler, development should go much smoother.
I've mentioned a couple times before that the first computer I really got to use was the Sanyo MBC-1000, a Z80-based CP/M machine. In the greater picture it was a largely forgettable machine with little to differentiate it from its competitors. Which is pretty much what has happened. There are a few units sitting in museums and the odd Reddit post of someone acquiring one, but not much real information.
So last year I started taking a closer look at the machine I grew up with to try to learn what I could about how it works. And in the interest of preservation and education, I've pushed my notes to a GitHub repository.
Reverse-engineering notes & documentation of the Sanyo MBC-1000 computer - techav-homebrew/MBC-1000
There is much more work to be done, but so far I've made an entry-level attempt at reverse-engineering & annotating a disassembly of the boot ROM, documented all of the components on the main logic board, documented the expansion card specifications including modeling the slot and mounting brackets in freecad as well as the board outline in kicad. I've also made an effort to reverse engineer a schematic for the serial expansion card — which as far as I am currently aware is the only official expansion card that was ever produced.
I plan to continue adding notes to this repository as I learn more about this machine. It may not have made any significant historical impact, but it was a solid machine that was more than capable of doing some serious work. I believe it can still teach us something and deserves to be remembered.
I do have a secondary motive for taking such a detailed look at this machine though — at some point in the last 20 years we misplaced the box containing its boot disks and other software. I have found an old Teledisk image of an MBC-1000 boot disk which does appear to have all of the important CP/M components (like the disk format utility, sysgen, and assembler), but there is no guarantee it will work. Beyond that, its floppy drives were never terribly reliable and out-of-production magnetic media does not have much life left anyway. I want to come up with some way to attach a modern storage device to the machine to breathe new life into it (a Gotek would probably be easiest since it uses standard Shugart floppy drives, but I would love to come up with a way to give it an SD card interface or something like that). All this information will be useful for developing anything new for this machine.
