ASR-33 problem

From: Tony Duell <>
Date: Fri Jan 23 21:41:19 2004

> > > My ASR-33 has recently started to apply 20V pulses to my TX+ line. I
> >
> > By Tx+ do you mean the keyboard loop? In other words, is it Tx on the
> > teletype or Tx on the computer?
> Sorry, I mean Tx on the computer. The 20V appears on the + side of the loop
> going to the TTY's printer, whenever the printer is actually printing. The
> computer doesn't like it much, either :-).

I guess I'd start by unplugging the 9 pin connector on the selector
magnet driver bracket. If you still get 20V on the loop, then there's a
short somewhere in the wiring on the call control unit (probably on the
relay). If not, then there's a problem in the selector magnet driver.
There aren't that many components in there, so it can't be too hard to
test the lot!

Received on Fri Jan 23 2004 - 21:41:19 GMT

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