Marty from Florida wrote:

Has anyone had this issue, and what is/was the resolve? I don't want
to pay a shop 4 hours for an easy fix issue.

I had a NARCO Mk-12D and a Quiet-Flite intercom in my aircraft. I found that the
sidetone was controlled by the intercom. If I wanted more sidetone, I had to
turn the intercom volume up (and turn the radio volume down to keep what's left
of my eardrums).

George Patterson
Whosoever bloweth not his own horn, the same shall remain unblown.