[GreenKeys] Teletype Model 43 Help needed

[RETRO Innovations]

I don't mean to impose on the list hospitality, but two folks suggested 
I join the list and share my requests, as I have recently acquired a 
Teletype Model 43 and would like to utilize it (as it were).

The unit powers on and is cosmetically in good shape with the paper roll 
dispenser (missing on of the platen knobs, the roll dispenser roller 
tube - someone cut some broomhandle to fit - and does not have the 
friction feed basket).  The unit powers on, and in Local mode, it will 
type on the paper and the bell works.  The ink was dry, but I softened 
it up with some solvent. It will print to the paper, so the dot matrix 
function works.  Paper feed and carriage return functionality all appear 
to work fine.

I have, though, been unable to get it to send or receive data via RS232.

I downloaded both the user manual (#367) and the 
operations/troubleshooting manual (#368) and looked over them both.  It 
appears I have the AAL model (some pins are missing on the RS232 port, 
but the manual indicates both AAC/AAD and AAK/AAL models have RS232 on 
the correct pins  - 2,3,7, etc.)

With the unit plugged in and connected a PC serial port, I tried the 
following permutations:

  * EVEN (434a) and MARK (434b) PARITY
  * PARITY switch on and off
  * 30CPS and 10CPS
  * TERMINAL READY and DATA lights on (DATA light just blinks)
  * 7E1, 8E1, 7N1, 8N1 from PC
  * Null modem and straight cable
  * HALF and FULL DUPLEX

Thinking that my serial port was not up to the driving task, I unhooked 
the cable and put on my rs232 troubleshooting tester.  I see a constant 
low on TX.  I then scoped the signal line, and the same shows.  The same 
happens with both TERMINAL READY and DATA switches selected.  DATA light 
blinks but then switches to TERM READY

Thus, before I continue debugging, I'd like to know if anyone has a 
similar setup and could let me know if there is some special wiring 
needed or if I need to set the config switches or the KB switches in a 
certain way.  My concern is that the driver circuitry is bad, and I'd 
like to exhaust all other solutions before I dig into that PCB board.

My other concern is the ink ribbon.  This ribbon is OK for now, but the 
ribbon itself is damaged, and the felt roller inside the cartridge looks 
to be disintegrating.  Thus, I am wondering if anyone in the list has a 
spare to sell, or if someone can rebuild these units.  I am happy to buy 
NOS or a gently used one (even if it needs reinking), but I checked and 
the normal sources are devoid of options.  It's not an urgent thing, as 
this ribbon looks to have some life left, but my fixes are temporary at 
best.

I know this unit is probably the ugly step child of the much more famous 
mechanical Teletype machines, but I perform demonstrations for 
enthusiasts, and this unit provides a great way to easily show how some 
computer I/O was done pre-CRT without the concern of dragging a much 
more valuable model 33 to computer shows and without the concern raised 
by a mechanical system developing problems during a demo or hands on 
exhibit.  Thus, I am glad to have acquired it.  It also helps that it is 
an actual Teletype unit, so part of the discussion with visitors can be 
the historical significance of the manufacturer.  As such, I'd like to 
get this unit running for that purpose, if it's possible.

Any help would be greatly appreciated,

Jim Brain
RETRO Innovations
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