[Collins] 30S-1 T/R DELAY

[Dr. Gerald N. Johnson]

On Fri, 2007-03-30 at 20:56 -0700, Cory Hine wrote:
> Has anyone had a problem and solution to the 30S-1 not
> returning to receive right away. It seems like the
> keying relay will hang.. and then release the amp back
> to the receive condition. This happens especially in
> the beginning of the use cycle, and goes away with
> time...
> 
> Cory/AD5QP
> 
Looking at the schematic in my yellow book, I see two relays, controlled
by a ground to transmit. Each relay has an RF and a DC contact. The
output relay is switched directly and its DC contact applies power to
the input relay. The DC comes from a half wave rectifier off the 6.3
volt AC tube heater winding. There isn't much there to cause a relay to
be slow to drop out other than the relay itself. Probably over the
decades the magnet core has become a bit magnetized from the DC
operation or the pivots have gummed up. A bit of paper on the pole piece
can help keep the magnetized relay from sticking and a quarter drop of a
thin oil or maybe DeoxIT contact cleaner on the pivots should clean them
up. Especially since it cleans up with warming up, I lean towards the
gummed up relay pivots.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer