[GreenKeys] WU 28ASR WIRING

[w9ddd at tapr.org]

Hopefully someone knows more about this than I can seem to remember.   Seems like there is something about the chemistry of wet cell batteries that lead to telephone and telegraph systems connecting the battery + terminal to ground.  I remember that British cars used positive battery ground at one time.  

John, W9DDD


> On Feb 13, 2021, at 4:59 PM, John Hargett <kg5ylg at austin.rr.com> wrote:
> 
> Getting thru my 28ASR that I got some time back.  Have it receiving ITTY now, able to also punch tape, as well as run tape.  Have a couple of questions that I am sure someone out there has more knowledge than I  ( that doesnt take too much) about these machines.  Two items I am looking at are:
> 
> 1)  The LESU, which is a Western Union 9797 wiring cabinet, has the positive side of the loop supply tied to ground @  C-2 and the negative floating.  What is the design behind this?  I have looked at other LESU wiring diagrams and do not see them showing this. Would it be detrimental to put the neg at ground potential?
> 
> 
> 2) When I run tape on the LXD, it comes out all random and missing CR and LF .  Ran a tape RYRYRY  and get not RYRYRY on print.  Does not LF or CR at correct times.  Tape was preceded by multiple LF and CR then LTRS, Ran 40 characters RY, followed by CR,CR,CR,LF,LF, then 40 more RY followed by CR, CR, CR, LF, LF, then 40 more RY followed by CR, CR, CR, LF, LF.  What i got on type was  a couple of  over types at the start, then KCBSCCBSCCBSCCBECCBECCBSCCBER then it did a single LF and continued with the same basic characters, then did a CR and same basic characters.  
> Is this a timing issue with the LXD signal generator? 
> 
> Dont know if it will come thru, but a copy of the 9797 wiring diagram is attached.
> 
> 
> Thanks in advance
> 
> John
> 
> KG5YLG
> 
> 	Virus-free. www.avg.com
> <wu9797wd.pdf>
> <wu9797wd_MKUP.pdf>
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