[GreenKeys] The Model 37

[Don Robert House]

The Model 37 Printer is quite cleverly designed so that at 150 baud
many of the parts actually move slower than at 110 baud. The selector
clutch has two stops instead of one, so each character is generated
in half a rotation of the main shaft.

Another unique design are the "two plates"... one front plate and one
side plate... together they provide for aggregate motion.
This allows the type box to go from one character pallet to the next
without taking time to go to home and then to the next pallet.

At our shop in Elk Grove Village, IL we (Don Dove and myself)
maintained the three 37ASRs at Western Electric's office in Rolling
Meadows, IL. We also were responsible for the Type 4 paper tape
Dataspeed sender, but that is another story.

We only had one case of trouble on the 37 typing units.  The ribbon
carrier... the ribbon kept popping off... Teletype designed a new
ribbon carrier and we never had another case in the few years we
maintained them. We routined the machines every 4-6 months as time
allowed.

The CX tape reader was never a problem since it was loafing in the
M37 application. However the M37 Typing Reperforator was a nightmare.
It was basically a model 35 reperf with a M37 selector and extra
parts to position the huge typewheel with upper and lower case
characters and all the special symbols.  Neither Don nor I were ever
able to keep them printing on the tape longer than two months and we
were never successful in repairing them.  We would replace the reperf
with a new one from Teletype and send the broken one back to Western
Electric. Apparently WECo was not able to repair them either as all
of the replacement units came packaged new from Teletype. I am told
that the typing reperf was eventually discontinued in favor of a non-
typing version that punched at 150 wpm without any problems.

Training on the M37ASR was limited to the mechanical portions of the
machine as there were ten different standard electrical applications
and Teletype would design the electronics just about any way the
customer wanted.  For example the military machines and the M37s that
were part of the Teletypewriter Test Boards in major cities had to be
able to send and receive in 5, 6, 7, and 8 level in Baudot, ASCII, as
well as TTS and at all offered data rates.  This was accomplished by
designing special YESUs that did the speed conversion electronically.
The typing unit always printed at 150 Baud, which was very strange to
watch at 60 wpm, as the machine would wait to type an (x) amount of
characters type them and wait again.

Gladly neither of us ever had a problem with the electronic parts of
the machines.

Some of the features offered were interesting.
Forward and Reverse linefeed.
Red and Black Ribbon.
On line Tab Set and Clear for both horizontal and vertical
tabulation.
Back Space
Optional New Line instead of separate LF and CR

As far as I know the WECo operators did not complain about the
keyboard, which was only slightly more comfortable than the M33.

As most customers were converting over to dot matrix printers the
demand for the M37 kept slowing down. At one time Teletype designed
a prototype keyboard based on the Model 40 technology but it never
went into production. Many of the machines were sold to the former
Soviet Union and also made available for Army and Navy MARS modified
for 5 level operation.

I actually enjoyed working on the M37 except for the darn typing
reperforators...

73,
Don K9TTY

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