I've just upgraded the keyboard on my secondary Apple /// to the Apple ///+ keyboard. I have the keyboard and bezel and obtained the correct encoder ROMs from Vintage Micros.
The system starts to boot, but stops with a SYSTEM FAILURE = $01 message on any boot disk. According to Apple docs, this means "BRK instruction from within SOS", which is pretty useless.
Is there anything I need to do when upgrading the keyboard other than replace the encoder ROM?
If you put the old keyboard/encoder back in, does the SYSTEM FAILURE go away?
No, dammit, it doesn't: even completely restoring the computer with its original keyboard, doing a "chip press", and re-seating the memory board doesn't fix things, which I suppose means that this /// is toast. Annoying, as it was working perfectly before I tried upgrading the keboard...
Now we can rule out the keyboard or the encoder as the source of the problem. Do you have an Apple II emulation disk you can boot? It doesn't use SOS, and may exhibit different behavior.
The emulator disk boots and seems to work-- I can go to the configuration screen, for example. However, when I press Return to boot into DOS, the computer beeps a few times and the screen fills with garbage, settling on a display of vertical lines separated by regular intervals. The disk drive never spins after I press Return; the crash is instant.
Memory problem, perhaps? I have a lot of spare RAM chips.
It could be anything, but I'd expect memory to be caught by the diagnostics at boot-up. That's another idea... you might try running a confidence or diagnostic disk (hopefully they will boot - none requires SOS):
http://apple3.org/iiisoftware.html#system
Good idea. Both disks boot. The Confidence Disk RAM test reports an error, but the visual "matrix" of memory doesn't show which chip it thinks is bad.
The Dealer Diagnostic disk correctly identifies the machine as a 256K machine, and crashes horribly when I try to run its RAM test.
Man, replacing memory on these things is a pain. I suppose I could try removing one bank of chips-- does anyone know which of the two rows of chips I should remove?-- and seeing if I can get it to work as a 128K machine. That would at least help me isolate the problem to a bank.
If it's a RAM chip and not a problem with the elaborate addressing circuitry. I suppose I could try swapping memory boards with my working ///, but I'm terrified of killing it, too.
Well, it's not RAM: I switched every single memory chip with a new NEC 4164, and the symptoms did not change.
The dealer confidence disk memory test reports no problems with only 128k of memory, but does report a problem with 256k, although the location of the problematic chip is not specified. The results are the same with either Apple or NEC memory chips.
No SOS disk will boot with 128K or 256K of either type of memory chip.
Since I first noticed the problem after swapping out the keyboard encoder I tried re–seating the chips in the vicinity of the keyboard encoder, but that had no effect.
I'm stuck at this point. Does anyone have any suggestions?