Subject: Teletype

From: Tore Sinding Bekkedal <[email-masked]>
Date: Mon Jun 2 14:56:31 2003

Whenever I type anything I just get a left-arrow. I am blaming the
1818-23/-21 for this. Shouldn't I?

OK; current loop.

Would this explain a resistor (14 Ohm, big) in the slot of the KSR would
get extremely hot when off this loop? Also; Hans Pufal, I would be most
grateful for the schematics for the CL>RS232 converter. Also tell me more
about the modifications made to the TTY control on the PDP? The card says
181823 on the solder side and 181821 on the other.

Thanks!

-Tore

"Life's a bitch and then you turn on your PDP and it's all nice and when
you turn it off it goes back to being a bitch. Repeat when nessecary. Oh,
and you die, btw."

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From: [email-masked]
Date: Tue Jun 3 09:06:44 2003

Hello all,

      I'm new to the list and have tons of old hardware (well...not
tons...but too much if you talk to my wife).  Anyway, in the ever present
hunt to expand my collection I've recently taken up the cause of collecting
Atari PC stuff with particular attention being paid to the PC-1.  I'm
*really* looking for the Atari EGA monitor as well as the external harddisk
but would be happy with the external 3.5 disk as well.

      Other than that I've only recently signed up on the list and I love
the content so far.

--
Damond Walker
Syncretic Software, Inc.
(302) 762-2600 x213

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From: [email-masked] (Tony Duell)
Date: Tue Jun 3 09:09:29 2003

> 1818-23/-21 for this. Shouldn't I?

Maybe. Does the Model 33 work correctly when switched to 'local'? If not, 
then you certainly have problems in the Teletype. If it does work in 
'local' mode, then you might still have problems in the Teletype, but 
problems with the interface are also possible.

> Would this explain a resistor (14 Ohm, big) in the slot of the KSR would

Are you sure it's 14 ohms? I remember a multi-tapped power resistor with one
tap being about 1400 ohms in the standard current loop electronics for 
the Model 33.

> get extremely hot when off this loop? Also; Hans Pufal, I would be most

And I think it does run hot. When switched to local, the teletype is 
_still_ a current loop device, but the transmitter (keyboard contacts), 
receiver (the selector magnet driver -- the little module with 2 
transsitors in the Teletype electronics chassis) and a 'local' power 
supply (which includes that resistor) are all in series. A current loop, 
but one entirely inside the Teletype Model 33.

-tony