[GreenKeys] 35 ASR current loop connections....

[Clay Archer]

My rebuild of my 35 ASR is going well.   I have just about everything
working in local mode.   Reads and punches tape and types correctly, and can
type and punch from the keyboard.   The rubber on the printing reperf print
hammer is missing, if anyone has a source please let me know (p/n 173979).
I also need the paper tape spool holder,  I could probably make something to
do the job.

 

I'm ready to try it "on line", but I need to work out the current loop
connections.    It had some cut wires connected to the lower 4 screw
terminals on the back of the power supply section (I think the book calls it
the "electrical service unit").  The upper 4 terminals are numbered 1 to 4
and is where the power cord connects.    The bottom 4 are numbered 5 to 8.
Terminal 8 has no connection.     On my 33ASR I have looped the input &
output with a current limited voltage (a small 6 or 9 volt battery usually
works) so I thought I would give this a try on the 35.   Connecting a
battery to terminal 5 & 7 or 6 & 7 will stop the chattering like it's
receiving a valid loop.   And it sometimes prints random characters when I
connect to these terminals.    However, when I type in line mode the data
goes to the punch instead of the printer.   The selector knob is set
correctly to the keyboard-to-print position and it works in local.    Using
a scope I can't see any pulses when I type on the keyboard on any of the
screw terminals (I applied a small voltage as a pull-up).  I also found that
if I jumper 5 & 7 or 6 & 7 (without a battery) it acts the same way.  

 

There are also 8 screw terminals on the back of the call control unit, none
seem to do anything.    Oddly, my call control unit consists of a
transformer and a relay.   The relay never seems to activate with any knob
setting or line/local.

 

Does anyone have any manuals on the 35 ASR?    All that I can find online
are for the KSR & RO.    The schematic for the KSR & RO shows it's quite
different from the ASR.

Any assistance you can provide would be appreciated.

Clay

 

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