13 May
2014
13 May
'14
11:36 p.m.
But secondly,
this is digital. It's a relay. It's a 2-stae device.
Sure, surrounded by some interesting things like 3 or 4 "thyractors,"
the characteristics of which I don't really understand all that well,
for example :). I jumpered a wire across the contact terminals of the
relay and still no
joy. The contacts on the reader control lever are OK (I cleaned those
thoroughly awhile back) I'll trace through the wiring tonight / tomorrow
(if I can find the time) and see where I can get with it.
If you get the 1975 Teletype Model 33 schematics from bitsavers, I think you need to look
at page
8 of the pdf -- sheet FS6.
It appears the reader trip circuit reduces to the trip coil (the one you worked by hand)
and the reader
contacts connected across the mains. So the problem could be a bad trip coil (let's
hope not!), bad
connections, or those contacts in the reader. I've had a lot of problems with those in
the past, and that's
where I would check first. With the machine unplugged from the mains, pull the reader
connector at the
back of the call control unit and see if you can get continuity between the pins of the
cable-mounted part
with the reader switch on, tape loaded, etc. If I'm reading the diagram right,
that's connector J6,
pins 14 and 15
Thanks as always for the advice; someday I hope not to
have to ask dumb
questions on this list :). (Don't hold your breath.)
It has often been said the only dumb question is the one that's not asked. I generally
go along with
that, although I do feel it's silly to ask a question when you know the chap you are
asking won't know
the answer... But that does not apply here. Ask away!
-tony