ClassicHasClass
Veteran Member
A very nice looking IMSAI 8080 arrived today in the mail. Packed along with it were the following:
Ithaca IA-2000 Z80 CPU card
TDL SMB system monitor board
Godbout/CompuPro Econoram XIIIa RAM board (32K). Haven't figured out what this is mapped to yet (I guess I should read the fine manual).
TDL Z16 RAM board (16K). The jumpers imply this occupies $0000-$3FFF.
Now, I should preface my stupid questions by saying this is exactly the second S-100 system I've ever owned, and exactly the first that was in any semblance of working order. My first was a questionably preserved Alpha Micro S-100 box which was more for historical interest than functionality. But I'd like to get this one to live.
I carefully checked everything before powering it on with no cards, and the front panel appears to light (but does weird things, to be mentioned).
Next I tried installing the CPU board. The Ithaca board has a 20-pin header for the front panel, but the panel connector has 16 pins. I guessed that it went in the rightmost 16 and it resets, runs and stops, at least. I powered it on with all the address toggles on zero. If I press EXAMINE NEXT, it advances its address bus lights. I didn't try to do anything else at this point.
Next I tried installing the Z16 board since I had a good guess that mapped to the bottom of memory. Here's where it gets weird. Going through memory with EXAMINE NEXT, data bits 0 and 6 light alternately. If I try to store with DEPOSIT, nothing is stored. Plus, some of the address lines now stick high, which may be why I can't store anything since they're indicating addresses outside of the Z16 addressing range. Toggling the switch makes no difference.
Am I an idiot, or is something wrong? What would be the next suggestion to try investigating?
Ithaca IA-2000 Z80 CPU card
TDL SMB system monitor board
Godbout/CompuPro Econoram XIIIa RAM board (32K). Haven't figured out what this is mapped to yet (I guess I should read the fine manual).
TDL Z16 RAM board (16K). The jumpers imply this occupies $0000-$3FFF.
Now, I should preface my stupid questions by saying this is exactly the second S-100 system I've ever owned, and exactly the first that was in any semblance of working order. My first was a questionably preserved Alpha Micro S-100 box which was more for historical interest than functionality. But I'd like to get this one to live.
I carefully checked everything before powering it on with no cards, and the front panel appears to light (but does weird things, to be mentioned).
Next I tried installing the CPU board. The Ithaca board has a 20-pin header for the front panel, but the panel connector has 16 pins. I guessed that it went in the rightmost 16 and it resets, runs and stops, at least. I powered it on with all the address toggles on zero. If I press EXAMINE NEXT, it advances its address bus lights. I didn't try to do anything else at this point.
Next I tried installing the Z16 board since I had a good guess that mapped to the bottom of memory. Here's where it gets weird. Going through memory with EXAMINE NEXT, data bits 0 and 6 light alternately. If I try to store with DEPOSIT, nothing is stored. Plus, some of the address lines now stick high, which may be why I can't store anything since they're indicating addresses outside of the Z16 addressing range. Toggling the switch makes no difference.
Am I an idiot, or is something wrong? What would be the next suggestion to try investigating?