[GreenKeys] Audio to TTY - Current Loop?

[Teletypeparts]

Cory,

If your 32 is a standard WU model, it needs 60 MA at 80 to 120 volts DC.  

Some after market Telex machines might be different.  Look at the circuit board behind and below the dial and see if it has a WU circuit board with a plastic cover over 3 relays and I think the number of the circuit board is WU 11272A or something close to that.  All older components, no IC's.  3 Molex plugs on the right rear and 3 smaller ones in front of the relays that go to the dial.  

When you apply 60 MA the correct way, the machine will start and stay on with a connect light.  

Wayne



-----Original Message-----
From: Cory Heisterkamp <coryheisterkamp at gmail.com>
To: greenkeys <greenkeys at mailman.qth.net>
Sent: Mon, Sep 17, 2012 4:04 pm
Subject: [GreenKeys] Audio to TTY - Current Loop?


Good News! Thanks to Wayne I now have the correct gearset for the 32.
lso got Eric's board- looks great.
Next step is a suitable loop supply. My 32 was a Telex machine and
ome sources I've read indicate they're expecting a 60mA loop.
owever, I've also seen 20mA referenced. Heeding Larry's advice below,
'd also not like to fry my input transistor. Can anyone in the club
omment on a proper supply voltage/current?
Thanks,
ory
On 9/7/12, Larry Tighe <larryradio at att.net> wrote:
 I changed my 32's to 60 WPM with new gears....to the best of my knowledge,
 they've become unobtainium....

 Also, if you run more that about 20 volts and 20 ma. into the Telex it'll
 fry the input transistor....be careful.  I'm told the range finder can be
 "adjusted" to make the machine see 60 WPM data.

 lar
 K2JIA
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