[GreenKeys] ASR 33 adjustments.

[Jones, Douglas W]

A student of mine and I have just finished with the second of the adjustments on the ASR 33 we're working on.

The Universal lever now works correctly both when you turn the motor by hand and when you run the motor and type on the keyboard.  The repeat key works too, so huzzah, the whole transmit mechanism seems in decent mechanical shape.

The paper tape reader was "stuck on", with power flowing through the reader coil whenever the TTY was plugged into the wall, so we traced the circuit to that coil from the local RDR supply.  All seemed well, but the logic was baffling until we figured out the trip lever - reader armature extension adjustment.  The trip lever interrupts the current through the reader advance solenoid, and when the trip solenoid is not powered, the reader armature extension latches the trip lever in position to break the current to the reader advance solenoid.  Being out of adjustment, it was never latching, so the reader was always running.  With that fixed, the reader now only runs when you push down on the reader armature extension.

This strikes me as a real kluge, except that it guarantees that the reader will be turned on and off at precisely the right point in the cycle.  What a marvelous bit of electro-mechanical engineering.

So, we have progress, but now, there is no current through the reader trip solenoid, so the question is, why -- another circuit to trace out, potentially miswired.

Also, I've sent a photocopy of my late 1965 Model 32-33 parts list to Al Kossow for Bitsavers, so someday soon, he might have it on line.  If anyone wants it sooner, it is a 4 Meg PDF which I will e-mail on demand.

I will be doing a similar scan of the late 1964 edition of the parts list, with first editions of about half the sections, but I won't hurry (it is water damaged and the pages may be harder to feed through the scanner).

		Doug Jones
		jones at cs.uiowa.edu