Ed Anderson wrote:

So check battery voltage to EC2, check CB wiring physically, beat your head against wall - Oops you're already doing that {:>)

...

Ed

Chris,

   Check the B+ voltage, at the EC2, in operating mode.  A weak
battery can show 12.6 volts when there's no current draw, but drop
to 10v (or lower) when there's a load on the circuit.

Dale R.
COZY MkIV #1254