[Kenwood] TS-120S PTT problem

[Michel Bartolone]

I've got an old TS-120S which seems to have a problem with the PTT 
circuitry.
The rig seems to transmit if I switch to "Send", or in VOX mode, but when I
key up the mic, nothing happens. The mic is a Kyokuto. I checked the mic
itself by running a DMM across the PTT terminals in the plug and it does
switch from open to shorted when I key the mic, so I suspect something in
the radio.

Is there anyone that can offer any suggestions?

Mike
KC9REL