I've had this problem several times. I'm not sure what fixes it but
eventually, after swapping batteries in and out among three 1500
series Aeros and cradles and batteries, the offending battery (or PDA)
starts working again. Then I put everything back where it was and it
usually works fine. Sorry I can't be more specific. It seems to happen
when the battery is completely discharged for a while.

Chip Bearden
ASW 24 "JB"
USA