Need PROM for ALTOS 8000

[wormey]

I have acquired an ALTOS 8000-12A. After fixing a few issues I still wasn't getting anything sensible from the console port so I checked the EPROM. Mostly 0's. (Same thing happened with a SBC-100 I have, still haven't got that one going yet.) Can anyone point me to where I can find an EPROM image for it? Google hasn't led me to anything, and while I have snagged a bunch of disk images and manuals, the EPROM is not among that lot. System: ACS8000-12A, motherboard 8500-0005, EPROM: 2716.
Thanks.

 

[SomeGuy]

I've attached a monitor ROM that I vaguely recall was dumped from an Altos 8000 a long, long time ago. I don't recall if it was the exact same model - I recall it was a Z-80 based Altos machine with an 8" hard drive, a tape drive, and an external 8" floppy drive.

 

[wormey]

Thanks. I'll try that.

 

[wormey]

Bleh. Still doesn't want to talk to me. I'll have to figure out how to do state analysis with my logic analyzer to see what it's doing. (Also needed for my SBC-100.) What's worse, it now sounds like the hard disk heads have crashed. :-( But it did activate the floppy drive a couple of times, so it's trying. And disassembly of the ROM looks like it's addressing the right ports....

 

[wormey]

I have downloaded the ACS8000-12 manuals, part 1, part 2, schematics. I have traced the outputs of the address decoder, and they match what is shown in the manuals.

The manual shows the magnetic tape unit (MTU) being addressed at 38H-3BH. This prom seems to reference tape interface at 80H-8FH. That's OK, though, as I don't have a MTU. So, this prom is not the proper one for this system, but the non-tape parts *should* be OK.

I have verified that the device initialization is happening properly (got the logic analyzer to do a state trace), but I'm still not getting console output except for occasional random garbage. So now I need to start checking the CTC and DART chips...