[GreenKeys] Model 35 Troubleshooting

[Nick England]

 The great thing about having a non-working unit is that you get the
pleasure of learning much more about how things work than if it came up and
worked perfectly on day one.

I only have experience on the M28, but I think the M35 is quite similar.
When you say none of the other keys work, do you mean you can't depress
them, or that you can depress them and nothing else happens? The more
descriptive you can be, the better the chance at remote diagnosis.

I'll refer to manual 281B vol 1
http://www.navy-radio.com/manuals/tty/jh/ttyman8/TeletypeManuals/model35/281b-v1-7304.pdf

NOTE - you can perform all of these diagnostics with the motor OFF and
turning it by hand. Sometimes that is a great way to see what is happening
bit by bit in a character cycle. The clutches won''t completely disengage
at the end of a cycle if the shaft isn't turning at speed but that won't
matter for first level diagnostics.

First verify that the signal generator shaft is continuously turning..
That's the shaft running from under the typing unit toward the front of the
set - it drives the keyboard clutch that cycles the keyboard when a key is
struck. if that shaft isn't turning it probably means that the typing unit
is not properly seated.
see 574-221-100 figs 1 & 2

If you can't depress a key, that sounds like the keyboard is locked. On a
M28 there is a lock-unlock (or receive-send) pair of buttons. Lock may also
be set by the stunt box receiving two null characters in a row, On the M35
the BRK-RLS key is the equivalent of SEND.
see 574-201-100 para 5.03

So depress that BRK-RLS key once and then see if you can depress other
keys. When you depress a key, the keyboard clutch should engage and cycle
once, transmitting the character (observe the sequential operation of the
transfer levers in the box to the right of the transmitter box), and then
resetting the keys and code bars.
see 574-221-100 figure 9 showing the transfer levers

The Local CR and Local LF should operate irrespective of the keyboard
operation - they are levers that go straight to the typing unit. You say
that LOC-LF works - that's good news!

What happens when you depress LOC-CR? Can you depress it? Do you hear any
different noise?

With the typing unit removed, make sure that the LOC-CR lever operates OK -
it should push the end of the local carriage return bail toward the ear of
the set.
see 574-221-100 fig 10
You can see on the typing unit where that bail is supposed to engage the
typing unit. With the typing unit removed, you should be able to manually
push that projection on the carriage return lever to the rear and have the
carriage return - it is actuated by the spring action of the left hand
carriage drum.
See 574-220-100 para 2.79

It is possible that the typing unit and local carriage return bail were
misaligned at some point and the bail got bent.

I am guessing that your unit has a LESU with a built in loop supply to
operate in LOCAL mode.
What model LESU do you have? - we need to look at a wiring diagram to help.
Again, provide as much info as possible.

SO - once the keyboard and printer are working OK in local mode, you can
move on to debugging LINE operation. If the external loop is open you will
get continuous spacing and the typing unit will simply "print" an endless
series of nulls - this is known as "running open". So figure out where your
loop is open. Disconnect your loop supply and use an ohmmeter.

Keep us posted and remember that all we can do is to make guesses based on
the information you feed us.

Have fun.
Nick England K4NYW
www.navy-radio.com


On Sun, Apr 19, 2020 at 11:37 AM Carol Fano via GreenKeys <
greenkeys at mailman.qth.net> wrote:

> Hi All,
>
> My KSR model 35 is clean, lubricated, and back together. Last night I gave
> it a test run. In local mode, the motor runs and the “LOC LF” key will line
> feed as expected. None of the other keys function and the carriage is at
> the right end and does not return.
>
> In on-line mode, the matching runs like its typing away, but the loop
> interface is not connected to anything. The carriage is also at the far
> right.
>
> I keep looking in the manual for ideas, but I’m not finding what I need.
> Hopefully one of you have some ideas. I saw a video about a similar problem
> with an ASR33, but it seems too different than the KSR35.
>
> Thanks and 73,
>
> Carol, K1CSF
>
>
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