Hi, I'm a novice at clock repair but I do restore antique automobiles so I'm not mechanically challenged. This Seth Thomas clock was cleaned and serviced about 3 years ago by a local clock repair person who had an excellent reputation. Unfortunately he retired and now I have to deal with this myself. The clock started chiming out of sequence recently, in the past when that occurred it would right itself within a short period of time but not now. Specifically, the clock chime is 1/2 hour off meaning that at 6:30 it will strike and chime as if it were 6:00. At the 1/4 hour it chimes for 3/4 hour, at 3/4 hour it chimes for 1/4 hour and on the hour it chimes for 1/2 hour. Please advise.

