Mohawk Data Sciences 6401 Schematic?

Jon Elson elson at
Sat Sep 7 20:46:59 CDT 2019

On 09/07/2019 08:11 PM, Cory Heisterkamp via cctalk wrote:
> Hey Guys,
> I recently picked up an MDS 6401 Key-To-Tape unit in NCR guise to park next to my keypunches. It's been in storage for a couple decades and is in pretty decent shape. Even has a tape on it from when the university that had it pulled the plug and sent it off for surplus. Found an internal date code of 1971.
> The unit does actually show signs of life, but I suspect a power supply issue. Does anyone have a lead on a schematic?
> This here is basically what I'm working with:
> Thanks,
> Cory
Wow, MDS was a REALLY small outfit.  Or. maybe there was 
another company in a related field with the same acronym 
MDS.  They made some systems for accounting, order entry and 
such that were not computer-based.  The data was stored on a 
4' diameter fixed-head disk, and they had a bunch of 
stations that looked like fancy desk calculators.  All the 
logic was in the stations, and was implemented with about 50 
ICs and wire-wrap.  But, I'm pretty sure this was made by 
Mohawk Digital Sciences.

I got a Pertec key to tape system on the surplus market in 
about 1981 or so.  It had a little core memory, a keyboard 
and a panel of lights so you could step through a record and 
view the characters. It came from the surplus outfit with 
schematics.  I found the right place to break into the logic 
and interfaced it to my Z-80 CP/M system.  I used it for 
backup.  (I added a Memorex SASI-bus 8" hard drive to the 
CP/M system, and didn't really trust the reliability of 
floppies, so mag tape was a good thing to use.)


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