Just thought I'd update:
As I said, Paul, your machine did not appear to turn on. So I opened both boxes and it looked as though there was a circuit board missing, compared with mine.
So I thought, why don't I switch the compasses? So I did. No biggie. I turned on the circuit and plugged my box in just make sure it still beeped when fed power and it did.
On a whim, I plugged in your box, now with the old compass in it, and it beeped!
Completely puzzled, as you can imagine.
NEWay, I went out Monday in flat water
and not much wind
and tested them both.
Both appeared to hold a course just fine.
I did the big circle thing, as suggested by Pogo, just for kicks, but the bottom line is that matters seem to have fixed themselves. I have no freaking idea why.
I will try again in a few days, when I get more challenging sea conditions, and will let u know if there's any change.
Electronics! Strange beyond belief.