Hi all,
Sorry to revive an old post but I wanted to add my story. I recently received a PAM 217 from a fellow member that was gaining one hour every four when it arrived..yes, that's six hours fast a day! Not sure if he sold it due to this problem, or if it took a knock in the mail. Anyhow, I tried nudging the balance spring thinking the coils might be stuck...no luck. Then I noticed that the outer coil was not moving because it had actually looped out around the regulator (or whatever you call the thing that holds the end of the spring). It took a good (and I'm sure risky) push to free it and the watch is now accurate to about five seconds a day. Amazing.
There is so much great information here!