UPDATE: At last I got around to replacing the encoder and then finally exchanging X and Y G320s and now X is missing pulses. AH HAAAA!
I ordered another G320 for an A axis addition a few days ago so will 'press' it into regular old three axis duty. Then maybe I can use this pile of iron instead of testing, setting up and replacing parts on it. Blah!
Thanks,
Bill C.