[GreenKeys] ASR-33 Chattering...and the beginning of an adventure!

[John Lawson]

Greetings Greenkeys and John!

My 33 ran open when I first got it - it had some mechanical issues as well, which got fixed.  But the "no selector magnet" fault became quite a rabbit hole - as I'm sure you'll find out quite soon - the Teletype documentation is rather obtuse and scattered - these machines were quite modular, and the prints cover various moduels and assemblies - the wiring diagrams are also like 'islands' of information - I found it definitely un-trivial to get an overview of my specific machine.

That being said - the education of puzzling all that stuff out was well worth it.

In my case - [long, long story very short] everything pointed to the selector driver power transistor - however static tests showed it 'good'. Because the circuit is floating, there are challenges reading stuff with unbalanced, ground-referenced test gear.

Turns out the transistor was oscillating instead of providing clean pulses. (Whiskey Tango Foxtrot?!? over...). replacing it with one that matched the specs from my drawers of Stuff cured the problem.

Mine still has one or two things: the 8th level is "on" all the time when punching, and I need to find (or just make) a chad box.  I don't care too much about cosmetics, as long as the machine runs.


Hope this helps....


Cheers

John KB6SCO

Carson City

On 8/31/2019 6:05 PM, Andy KN4UCL wrote:
Hi John - you are running "open."  I am sure Wayne will chime in (he's the resident expert) - that video is actually my humble (ebay) TTY that Wayne very graciously helped me fix. It now runs perfectly.
If you don't hear back from Wayne I can dig out the emails, but suffice to say - WELCOME to your model 33 … it's a lot of fun :-)

Andy

On Sat, Aug 31, 2019 at 3:34 PM John Kelley <jkelleyus at comcast.net<mailto:jkelleyus at comcast.net>> wrote:
Good afternoon everyone! I've just managed to acquire an ASR-33....an
item I've been searching for about 2 years. I first used one of these
while playing with early PC's in the 1970's and later used one
on-the-job connected to a PDP-11.

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