http://users.glitchwrks.com/~glitch/202 ... -ii-repair
I bought this one off Herb Johnson a while ago at a previous VCF East in known non-working condition. Herb knows I like OSI stuff and had no inclination to dig into it himself. It came with a bunch of poorly applied modifications from some previous owner, which I unfortunately did not get pictures of. I ended up stripping it off in the course of repairs.
This is one of those systems where I feel like it pays to get out the logic analyzer early, so I set it up with one of our HP 1650As. I had a generic 6502 machine definition saved on diskette, from KIM-1 repairs, so I copied that and customized it for the Superboard II. Most of the signals were brought over from a 40-pin DIP clip, with a couple grab leads to pick up things like the boot ROM chip select.
The problem ended up being the leftovers from what appeared to be an aborted RAM modification. There were solder bridges on the top side around some of the RAM sockets. I'm guessing someone was going to tack flywires on there and double-stack some 2114s to double the onboard RAM, which I've seen done on other Superboard II systems. I've also seen a much more professional looking mod board for it
After cleaning that up, the system came up and ran BASIC from ROM just fine!I've upgraded this Superboard II to CEGMON, and will likely use it to design a Superboard II => Glitchbus interface to hang off the 40-pin expansion header.