[GreenKeys] 28 ASR running open

[Sarah Autumn]

Hi Nick,

Just figured it out late last night. It's funny that you mentioned there
are a gazillion different ways that ASRs can be hooked up. I noticed that
the previous owner had installed jumper wires across the cabinet terminal
blocks, and I suddenly grew suspicious of them. In a fit of late night
ambition, I removed them, and wired the keyboard jack from the acoustic
coupler onto the correct terminals, and now it works.

The mystery is what those jumper wires were doing in the first place, and
why it worked previously.

Oh, by the way, I wanted to get in touch with you about the manuals at
navy-radio! I'm a regular volunteer at the Museum of Communications in
Seattle, and I've been digging through our Teletype stuff. We have tons of
documentation there, and I was wondering if maybe you wanted me to send you
a list of what we have? Maybe we could help fill in some of the missing
documents in the collection there, or at least provide higher quality scans
if needed.

On Fri, Jul 17, 2015 at 7:53 AM, Nick England <navy.radio at gmail.com> wrote:

> Not sure how your modem connects to everything, but it sounds like you
> have the signal generator wires on a plug that goes into the loop.
> So all the signal generator should do is make contact for a mark, no
> contact for a space. The rest position should be a mark and then a space is
> the start bit.
> Sounds like your BREAK key is stuck or a wire is disconnected or the
> signal generator contacts have burned - something that causes a permanent
> open circuit.
> I'd pull the keyboard out of the loop (to make sure there is no voltage
> present) and just check things with an ohmmeter.
> A) one side of keyboard plug to one side of signal generator
> B) one side of signal generator to other side of signal generator
> C) signal generator to other side of keyboard plug.
>
> It's gotta be in there somewhere......
>
> OH, this is an ASR - which means your TD is hooked up in there somewhere.
> Is the TD plugged in?
>
> There are about 1000 ways that ASRs are hooked up. One wiring diagram is at
> http://www.navy-radio.com/manuals/tty/28ASR_wiring_W0700.pdf
> http://www.navy-radio.com/manuals/tty/wd-tty-7015-7016.pdf
>
> Good luck!
>
>
>
> Nick England K4NYW
> www.navy-radio.com
>
> On Thu, Jul 16, 2015 at 9:04 PM, Sarah Autumn <neverether at gmail.com>
> wrote:
>
>> Hey all,
>>
>> My 28 is running open, and I feel like I'm missing something obvious.
>> I'll try to provide a list of what I have, and what I've done...
>>
>> -Pretty much stock 28 ASR, though it has been modified for the deaf, and
>> I provide loop current with an acoustic coupler modem.
>> -Previous to last week, it ran without any problems.
>> -Runs fine as long as keyboard is not plugged in to the loop. I also have
>> an original 100A Teletype Test Distributor, that I've plugged in through
>> keyboard plug of the modem, and it works great. The typing unit behaves
>> properly.
>>
>> So I don't think it's the modem. I've checked the signal coming out of
>> the contact box / signal generator, but I'm not sure what I should be
>> looking for. I get constant voltage on one terminal, and constantly no
>> voltage on the other. Hitting keys seems to have no effect, though the
>> little wiggly bits inside wiggle nicely.
>>
>> Symptoms started when I had the typing unit out to work on the stunt box.
>> Finally got that how I want it, and when I put the typing unit back in for
>> the last time, a wire on the connector must have gotten stuck, and it
>> shorted. I fixed the wires, and the TU appears to be fine.
>>
>> What am I looking for coming out of the signal generator? Am I barking up
>> the wrong tree?
>>
>> Thanks :)
>> Sarah
>>
>>
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