[GreenKeys] Cashion Electronic ST6 converter

[Ralph Irish]

Jim & Tom

A Navy MARS group took the ST-6 design and sort of 'modernized it'.  At the time Hoff did the initial
design, the 741 chip was either non-existent or too expensive to consider for the TU.

The 741 is a 'data-equalized' version of the 709 chip.  The 709 became 'data-equalized' by the addition
of four or five components at various parts of the chip's pins.  If you look at the schematic, you will
see all but the front end 709 have much the same, if not identical set of resistors and capacitors to
do this job.

The 741 was 'built that way' and didn't need the extra components.  So they were used in all but the
'front end' of the TU.

This Navy MARS group was looking for a way to automatically forward MARS messages through the system with
as little 'hands on' work as possible.  One of the things they figured would help would be for as many of
the members as possible to have the DT-600 TU and various accessories to make as many stations either
automatic or 'semi-automatic' when it came to routing messages around the country and the world.

Most of this was before a lot of computers graced hams' shacks.  The advent of easily obtained computers
and compatible software  changed the way MARS routed messages.  TUs were still needed, but most of the
work was done by computers after some point.

There was also a similar version of the ST-5. which had a lower parts count, and this was suitable for
VHF and UHF work where signals were better and stronger.  They made a DT-500 which was the ST-5 which used
the 741 chips where possible.

They also made a speed converter board, a UART board and perhaps some kind of memory board to make a system
a bit better than 'standard'.  

I had a good friend who was in Navy MARS at that time and he had some of the 'upgraded' hardware in his
shack.  Unfortunately, not long after that he finished college, retired from his job and got a great job
out in Arizona with Motorola and his activity in MARS came to a halt.  

The boards for these devices used 22/44 pin edge connectors.  He and I discovered some kind of a prototype
computer system that had close to 800 of these edge connectors involved before it was scrapped.  We got the
whole mess for a song, and spent hours 'unwrapping' thousands of connections to make the connectors 'clean'
for use.  There were also some 'bussed terminations that went across 20 or more connectors.  He became the
'go-to-guy' for those who wanted a deal on edge connectors.  They went fast!  I had a handful of them left
for myself and they got lost in the corners of my basement for years.  I found them and made mention on
G/K and got a few who wanted some for whatever they were building.  Just three or four left now.

Anyway, if you should run across something called a DT-600, you might consider getting it and having a decent
TU to use.

I am not familiar with Cashion Electronics.  They could have produced a quality item, but maybe not price
competitive to the better known HAL version at that time.  

Hope this provides more clarity than confusion!

73,

Ralph - W8ROI

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On Jul 1, 2019, at 1:18 AM, Jim Pruitt wrote:

> Does anyone happen to know anything about a Cashion Electronics ST6 converter?  The question was asked on another list.  I had never heard of 
> Cashion Electronics, Box 7307, Phoenix, AZ
> before and Mr. Startpage (pronounced Google) was not my friend!  I knew of a couple of versions of the Irv Hoff Mainline ST6 besides the Hal kits.  I knew one version placed the entire converter and filters on one big pc board rather than several plugin boards like the HAL.  Are any of the versions any different than W6FFC's original design?  Has anyone ever heard of Cashion Electronics?
> 
> Thank you.
> 
> Jim Pruitt
> WA7DUY
> 
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