[GreenKeys] Troubleshooting 35 ASR Printing

[Nick England]

See I knew I shouldn’t type while still half-asleep and without a machine
in front of me. Selected keyboard code bars spring to the right, not left.
Oops.

On Sat, May 25, 2019 at 8:38 AM Nick England <navy.radio at gmail.com> wrote:

> With the motor off, press a key that should cause the sticky bits to mark.
> According to your diagnosis, those keyboard code bars will be released but
> won’t move left like they should.
> So try to move them by hand using a screwdriver to gently push. Maybe you
> have gunked up grease so they can’t move easily.  Maybe they have missing
> springs so they aren’t getting pulled left.
>
> If the code bars won’t move with a bit of pressure, then they haven’t been
> released or something is bent or blocking them. You may need to remove the
> typing unit and then remove the keyboard base from the cabinet. so you can
> turn it on its side to see what’s happening on the bottom. Watch some code
> bars that are operating properly to compare to the problem area.
>
> If you take remove the typing unit, you can turn the keyboard drive shaft
> by hand to go through a keyboard cycle. If the typing unit is still in
> place, you can just turn the motor.
>
> Note. When cycling by hand the keyboard shaft clutch won’t release at the
> end of a cycle (because you aren’t going fast enough) but that won’t matter
> for manual testing.
>
> Written from often faulty memory. I’ll probably have to issue multiple
> corrections when I wake up and look at a machine!
>
> Or maybe I am misreading and your keyboard code bars are working ok and
> the problem is in the printer. My experience there is that the culprit is
> often gunk in the levers and push bars that connect selector to code bar.
>
>  I wish we had instant teleportation so we could look at it together.
> People who have been to teletype school must have had a great advantage
> over those of us trying to learn in isolation.
>
> The teletype is a wonderful piece of mechanical digital logic. Sticky bits
> are caused by obstruction (equivalent to a grounded signal line in
> electrical logic) or a missing spring (like no pull-up resistor).
>
> Good luck and Have fun solving the puzzle!
> Cheers
> Nick
>
>
> On Fri, May 24, 2019 at 10:20 PM Ken Wiebe <me at networkguy.com> wrote:
>
>> I read the doc on the typing unit and also some helpful replies to an
>> earlier thread, in an attempt to chase down why I don't get expected
>> characters to print.
>>
>> Based on an analysis of the characters printed vs key pressed, I believe
>> I have the issue "traced" to code levels 1 and 5 not marking.
>>
>> I think most, if not all, printing anomalies I'm seeing can be explained
>> by 1 & 5 never marking.  There does seem to be some intermittent shift key
>> anomaly (it doesn't work right away sometimes), but other than that I think
>> if I can fix 1 & 5 it will make a huge difference.  Perhaps the shift key
>> issue is a problem with level 7 (?)
>>
>> I said "traced" above because obviously more tracing is necessary.  I
>> observed the code bar shift levers in operation and I attempted to follow
>> in the doc the description of operation, but I'm not sure where to look
>> next to isolate further why the levers responsible for levels 1 & 5 would
>> fail to mark.
>>
>> Any hints what to do next?
>>
>> Ken
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> --
> Nick England K4NYW
> www.navy-radio.com
>
-- 
Nick England K4NYW
www.navy-radio.com
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