snhirsch at gmail.com
Mon Apr 5 13:28:56 CDT 2010
On Sun, 4 Apr 2010, Steven Hirsch wrote:
> I am working at bringing up a N* Horizon system and have some questions. At
> present, I don't have any system software and am attempting to determine
> basic functionality.
> The box currently has a Z80-A CPU card, HRAM64 memory card and an MDS-AD3
> hard-sectored floppy controller (others have been removed temporarily). There
> are two built-in SA-400 SS 5.25" drives.
> Other cards that came with the unit include a Compupro bus terminator, A
> Morrow Disk Jockey 2D/B 8" controller and a Morrow HDCA-4A hard disk
> controller. Unfortunately, the 8" Morrow hard disk emitted some magic smoke
> at power up and I have not done any further troubleshooting yet. Anyone know
> anything about Memorex 8" drive mechanisms?
> At power up, the system tries to boot the first floppy drive, then gives up
> after 10-15 seconds. I take this as a sign that some life exists. Then, I
> connected a PC running ProComm Plus to the left serial port, but cannot get
> any reponse or output there.
> So, problem 1:
> Where are baud rate settings documented? I can find pinouts for assigning
> signals on the DB25 connector, but not a mention of baud rate.
> Is it possible to obtain any sort of monitor prompt in the absence of a
> booted system? Doesn't the floppy controller have some sort of ROM monitor
> Any tips for getting a terminal connection operational? I have played with
> handshake signals a bit, and it sure looks like both parties have the
> necessary lines in the necessary states for communication to occur.
Following up my own post: I did find the baud rate jumper hiding in plain
sight on a different page of the backplane manual.
I've also concluded that there is no reason to expect a monitor prompt
from the system, seeing as there is no monitor ROM. I did not realize
that the disk controller PROM is only a rudimentary bootstrap loader :-).
I'm planning to populate the EPROM option on the CPU card and install a
copy of Dave Dunfield's little transfer program to see if I get things
Still do need some information on the Memorex drive mechanism. It was
sold as a Morrow M-20 disk system, but I cannot find a shred of
information on the drive itself.
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