Hank,
If you have a Ray Allen stick grip, as I do, you might lay a small piece of
electrical tape between the trim circuits and the PTT switch contacts.

I had a situation where, when I squeezed the grip, the PTT would ground to
the trim circuit. This would open the mic and transmit on the radio.
It might be external, as you suggested, or internal with the close proximity
of the wires.
Regards,
Tommy James<><

"Incidentally woke up last night and realized why the rudder trim went to
full left trim when I keyed the push to talk switch.  The trim buttons are
on the top of the stick and the PTT is on the front.  Keep your thumb off
the buttons."

Good luck with your Airplane. --- What kind of airplane?

Hank

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