Problems with Becker

I have a Becker 3201 radio in my glider that has a problem. With a
fully charged 14 V system I find that when I push the PTT switch the
display starts to blink and the radio then transmits a garbled buzzing
noise. A friend thinks that the flashing is a low power signal and
that the 24 year old wiring may be offering enough resistance to cause
a voltage drop. The radio receives just fine. Anyone know or heard of
this problem (and the fix) in the past? TIA

Mike
KV