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[TenTec] Orion key stays down in Writelog

To: tentec@contesting.com
Subject: [TenTec] Orion key stays down in Writelog
From: K4IA@aol.com
Reply-to: tentec@contesting.com
Date: Sun, 8 Feb 2004 23:54:49 EST
List-post: <mailto:tentec@contesting.com>
To recap the problem:

I was using the opto-isolator circuit shown on page 55 of the Writelog manual 
to key the rig.  The rig would go into transmit and not send dit and dahs and 
stay in transmit until I unplugged the key or sent something with the paddles.

Now, I have no idea but for some reason the opto-isolator circuit just would 
not work.  It seemed as if the opto was holding the key down.  The voltage to 
the DTR line would fluctuate with the keying and go back up to minus 9 when it 
was finished.  The resistance across the key side would stay low so the key 
stayed keyed until I removed the jack or keyed the rig with the paddles.  I 
tried two different optos so I don't think it was defective.  I also tried a 
couple of different resistors instead of the 560 shown in the book.  Nothing 

I switched over to the other circuit shown for the LPT port.  The one using 
the NPN transistor but I hooked it onto the DTR line of the serial port.  It 
works like a champ.

So problem solved and I don't know why.  Just put this in your book of tricks 
in case someone else comes up with a similar issue.  I don't know enough to 
tell if this was my computer or the Orion. However, the Orion does show 4 volts 
across the key line.  Is it possible this was working against the opto?  

Radio k4ia
Craig "Buck"
Fredericksburg, Virginia USA
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