18 Jun
1997
18 Jun
'97
4:43 a.m.
On Wed, 18 Jun 1997, Marvin wrote:
I need another project :) and I was thinking about
building the Mark 8
computer. Somewhere, I seem to recall that someone was having the board
sets for this computer made up, does anyone out there know or remember
who might be doing this?
That would be me...
This was the computer that appeared on the
cover of Radio-Electronics sometime (as I recall) in 1974 and predates
the Altair. I am starting to actively look for the Intel 8008
microprocessor but so far no luck. But that's okay, I still have a LOT
more friends and people I know to bug about it :).
The truth (and the chips) is out there...
As I recall, it had about 6 boards in the board set
and a bunch of TTL
chips, but I don't recall if the boards were single or double sided.
Double sided. The new boards should be pretty neat.
If anyone has the artwork, either on film or as a
template, I would be
interested although I *think* the PCB layouts were included in the
Magazine (haven't pulled it out yet to check.)
Sorry, no. To get the PCB layouts you had to order the 'supplimental
document pack' for an extra $5.00 (long out of print, bit I have copies)
Unfortunately, the plates used for the original printing appear to have
been overexposed and there are a number of places on the layouts where
traces and pads have blurred together. So, in short the original layouts
are a good reference, but largely useless to work directly from.
Additionally, there are three components (aside from the 8008) that are
either no longer in production, or don't have current functional
replacements. These being the 1101 (256x1) RAM used in the prototype, and
some latches used in the address/memory buffer board.
So... since we were confronted with doing (pretty much) new board layouts
anyway, we are also going to do redesigns of the memory and address/memory
buffer boards to allow the use of more readily available components.
(2102 (1k x 1) RAM for the memory, and I'm still checking on latches) The
unit will be functionally unchanged. I'm also considering making a
limited number of unmodified memory and address/memory buffer boards
is there is sufficient interest. (or if someone is sitting on a potload
of these latch parts!)
In any case... I need to complete the workup on the address/memory buffer
board changes so I can send the last updates over to my layout folks so we
can move forward on the boards... All I need is about another 2-3 days in
a week... B^{
-jim
---
jimw(a)agora.rdrop.com
The Computer Garage - http://www.rdrop.com/~jimw
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