5 May
1998
5 May
'98
2:31 p.m.
I dunno about
this display board. There were a few graphix cards
built for these. I have some old magazines that may yield a clue . .
I found the installation instructions for this slipped inside one of the
other manuals. It is what I thought it was - and there's an extra switch
on the back of the machine (mounted in the '488' hole) to select
alphanumeric only, bitmapped only, or both. I can't remember the
maker/model numberm but it was made in England (Chew Magna, near
Bristol), so I doubt if you'll have info on that. I may be able
to help with the FDC print, assuming it's H/Z standard
issue (that's what I have). There were at least two other third-party
It _is_ the Zentih board. On the other hand, tracing out the missing
schematics (terminal logic, the 2 disk controllers, the Siemens drive,
and the graphics board) won't take _too_ long - they're not complicated
and I have a lot of clues about how they work (like block diagrams,
circuit descriptions, data on all the chips, etc). I would claim 'Zenith docs are excellent',
based on what I've already got!
Yeah, they were on the ball, weren't they? Zenith owed this to their
Heathkit roots.
I _think_ I have all 40 track drives....
The Siemens drive is definitely 40 track, but if the external drives
are in a Zenith cabinet, then take a look inside. If they're CDC
drives, they're most likely 80-track. If they're Tandon, Shugart or
MPI, then most likely 40 track.
I forgot to mention, if the machine and won't always boot from the
Siemens drive reliably, you may have to adjust the spindle rotation
speed of the drive. There is a special program you run and a
procedure in the manual to do this. Shouldn't be needed though, it's
usually a set 'n ferget deal.
-- Jeff