Microair M760 Intermittentent Transmit

Reception is good and, until recently, transmission has been good, as well.
Lately, transmission has been intermittent. The radio transmits carrier,
but no modulation. I have gotten a few false starts since one time moving
the boom microphone caused it to transmit again. Thinking of frayed,
chafed, or broken wires, I dismantled the mic but found nothing wrong.
Looking further, I found numerous splices in the mic wire and I'm in process
of replacing it in its entirety.

With the mic wires cut, I measured around 9.5 Vdc between the conductor and
the shield (pins 1 and 2 of the DB15 connector.

A friend happened by and told me that he had heard that Microair radios of
my vintage had a known problem wherein there were two circuit boards mounted
at right angles to each other and, over time, vibration could cause a
connection to break. Has anyone else heard this?

Is there a Microair repair facility in the US?

Thanks,
Dan, LAK-17a, 5J