[GreenKeys] TTY Mod 33 adjustment progress

[Jones, Douglas W]

We've made progress on the Model 33 we're fixing here at the U of Iowa:

We had a problem with only being able to print odd-letters, giving:
You type:  ABCDEFG 0123456789
It prints: ACCEEGG 1133557799

I found that the rear rail of the carriage was out of adjustment.  Adjusting this was "lots of fun".  I actually had to buy a new foot-long screwdriver to reach the right-side mounting screw, and then grind it a bit narrower to fit the screw.

Then, to the cause of the even-odd problem.  The carriage stop plate and guide plate reset were both out of adjustment, causing stop-slide number 1 to hang up in the up position.  After adjusting these, the print trip lever release needed, but then there was a huge improvement as seen in the second photo here:
-- http://homepage.cs.uiowa.edu/~jones/pdp8/UI-8/log.shtml#2016-09-27

This is a big step:  You can now type readable but garbled text!  The first-letter spacing problem is obvious (but each time we remove the platten to get at other adjustments, we'll have to re-adjust the dash pot, so this will be put off for last).  More important, on random keypresses, it stutters, so you type just O and it gives OOO, and every once in a while, it seems to randomly substitute letters, for example, N for F, or back-arrow for W, or up arrow for T.

My guess is that the stuttering has to do with fine adjustments needed on the distributer clutch, but it could be something hanging up in the keyboard.  Some time ago, we found a bit of trouble with the repeat latch there  (the repeat key does work).  We'll attack that next.

		Doug Jones
		jones at cs.uiowa.edu