Just fixed a fast running watch more by luck than judgement. The movement in question was an ETA 2836-2 , it was gaining nearly a minute every half hour or so. I used the search button and found a miriad of possible reasons for the dilema I was facing. The two most likely reasons seemed to be a magnetized movement or a dirty/gummed up hairspring. One solution for a gummed up hairspring was to seperate the hairspring carefully using a small screwdriver, I didn't fancy prodding away on such a delicate mechanism so I decided to use a different method. This simply involved opening the caseback, letting the movement run and blowing in the vicinity of the hairspring with a watch dust blower. As I did this I noticed the balance wheel begin to spin further and faster. Wether this opened up the hairspring or removed a bit of dust or debris I don't know, but the movement is now running in sync with the clock I'm using as a reference. I'll monitor the watch for 24hrs then adjust + or - using the adjusting screw and hopefully get it to within 3 secs either way as I have with my other watches. I hope this post may help another member facing the same problem and at the very least offer a possible solution before having to try out more drastic/technical methods. 