[TenTec] KR-50

[JEFF S JOHNSON]

I recently acquired a KR-50 keyer and after some minor work on the paddle
mechanism and getting use to my first set of paddles I have grown very
fond of it.  Amazed I finally can send clear CW at over 40 wpm never
thought I could do it without a keyboard and even that is impossible the
way I type. 

One thing I am having a problem with is trying to track down an
intermittent hang up in it. About once every 15 minuets while sending,
the relay holds closed and stays there until I hit one of the paddles.
It's hard to get it to stop on a hang up due to the paddle action of
sending. I have determined that it is not anything mechanical like a
wire, switch , or bad solder and I've changed most of the transistors and
diodes in the timing circuit. I have changed the IC-4 a 7400 and no luck.
 Before I order a 7476 for IC-5 I wonder if anyone has any suggestions to
nail this thing down. It's not a big problem and most times I don't miss
a beat but I do feel the little miss and get a long dah or dit.

I'm not real sure how to go about tracing it down while hung up with
voltage meter or anything.  When it does stick it will stay that way till
one of the paddles gets taped so I can pull the cover off and check the
board. I know the relay is getting voltage through Q5 but I'm lost past
that point. I'm also sure it's not in the over ride circuit via the
little red panic button.

Thank you, any help will be appreciated.    Jeff   aa8ve
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