[GreenKeys] Model 28 asr problems

[Nick England]

I think that the MS switch will short out the keyboard and TD contacts,
leaving you PRINTING only.
That's from my notebook many years ago - I didn't have the official wiring
diagram then, so I traced out all the wires...

Nick England K4NYW
www.navy-radio.com


On Thu, Feb 6, 2025 at 3:22 PM Nick England <navy.radio at gmail.com> wrote:

> It isn't clear what you mean by "the magnets come on" and "the magnets
> stop" ?
>
> The printer is either
> SPACING (magnets not energized and machine running open like it is trying
> to continuously type blanks)
> or MARKING (magnets energized and machine not typing or not running open)
> or TYPING characters
>
> You have a 9797 WU electrical service unit like this one?
> http://www.navy-radio.com/tty/28asr/rest4/28asr-lesu-210.JPG
> The wiring diagram is here -
> http://www.navy-radio.com/manuals/tty/wd/wu9797wd.pdf
>
> The outside signal loop runs through the polar relay - the loop is
> polarity sensitive.
> If you have the polarity wrong, the machine will run open.
> Terminal 1 is negative, terminal 2 is positive
>
> ON SOME MACHINES (as penciled in on that wiring diagram) terminal 2 was
> grounded to the chassis - this is a bad practice!
> Unhook whatever wire is grounding your loop, because your signal loop
> might already have negative grounded.
> This drove me crazy and shocked me until i figured it out.....
>
> Good luck!
> Nick England K4NYW
> www.navy-radio.com
>
>
> On Thu, Feb 6, 2025 at 2:02 PM abowman89 via GreenKeys <
> greenkeys at mailman.qth.net> wrote:
>
>> So im back working on my western union m28 asr machine that's been
>> kicking my butt.   I have most of the problems ironed out but I'm down to
>> this,  the printer magnets only come on with the line test switch on and
>> the ms switch to the right.  If you turn the machine switchon on it or line
>> test or ms switch, the magnets stop. Any good guesses?  My gut says it's
>> something in the electrical service box but I haven't spotted it.
>>
>>       Andy b
>> ______________________________________________________________
>> GreenKeys mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:GreenKeys at mailman.qth.net
>>
>> >>> Jordan Spencer Cunningham's GreenKeys Search Tool:
>> https://teletype.net/gksearch
>> >>> 2002-to-present greenkeys archive:
>> http://mailman.qth.net/pipermail/greenkeys/
>> >>> 1998-to-2001 greenkeys archive:
>> http://mailman.qth.net/archive/greenkeys/greenkeys.html
>> >>> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
>> http://comcents.com/tty/greenkeyssearch.html
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to navy.radio at gmail.com
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20250206/ccfbbe5b/attachment.html>