Hi: I rented a P65+ (v-mount) from a rental house in San Francisco who has been unable to help.
The back came with several cards: 4GB, 8GB and 16GB -- all cards reported to have worked with the back in the past. The tech even said he tested the back and took some shots with the back mounted to a 503CW in house.
Now, 3K miles away, I open the case, and try to start up the camera and it doesn't recognize any of the 6 cards. The back will not format the card (error message from the format menu: "disk not ready").
I''ll have a very upset bride tomorrow is we can't figure this out...