Calibration gets stuck in a loop

Hello.

Do a soft or hard reset (pin in back of PDA; pin in back of PDA and front silver button simultaneously).

If not, what worked for me is to take the PDA apart, if you are comfortable. There are 4 screws in the back. Remove them. With a knife, flathead screwdriver or other flat object, pry open the back. A few plastic pieces may fall out, tho. Note where they connect. Disconnect and then reconnect the power adapter. Put the plastic pieces and the back of the PDA together. The back should snap in place. Insert the 4 screws. Should work OK, again. Use this method if the adapter is not charging very well and the soft / hard reset doesn't work. I've had to perform this many times. Good luck.