[GreenKeys] Searching for Answers.

[Harold Hallikainen]

It's amazing how Teletype made something electrically simple quite
complicated.
There's a wire in there for every possible option. I find their schematics
very
difficult to follow. Luckily, the one I have just powered up. The one I
had in high
school was another story. I pulled out all the wiring and brought out six
wires
(plus safety ground). A pair for the magnets, a pair for the keyboard, and
a pair
for the motor.

The fact that you see full voltage with the motor removed and a very low
voltage
when the motor is present makes me think there is a high impedance in there
somewhere. This could be an RC filter across a switch or relay. Apparently
some
units have a motor control relay (I've never seen this, but I see it in some
schematics). If it is not present or is not operating, a jumper would be
required.
Also, the toggle switches used in Teletypes seem to go bad. I had to
jumper the
on/off switch in my 14 TD to get the clutch release to work. I still find
it strange
that they put that switch in that circuit when the tight tape switch is a
couple
inches away. If anything, I'd expect there to be a motor on/off switch. I
now have
it plugged into a switched outlet strip.

As has been pointed out, an ohmmeter as a continuity checker would be
good. The
trick is figuring out where all the wires are supposed to go! You might
measure the
voltage across the on/off switch with the motor present. Does it go to
zero when the
switch is on? Is there a motor control relay?

Good luck!

Harold
https://w6iwi.org


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