Zenith Z90

From: Jeff Kaneko <Jeff.Kaneko_at_ifrsys.com>
Date: Tue May 5 21:31:01 1998

> > 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.

Well ya never know. They published all sorts of things in the
> > 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'm pretty sure I have the print(s), then. I'll check archives . . .

> 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
Received on Tue May 05 1998 - 21:31:01 BST

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