Sounds like your timer has gone bad.
Let me ask you this. How mechanicly inclined are you?
A) I can fix anything with a pair of pliers and some bailing wire.
B) Tell me how to get to it and I can do the rest.
C) Need full instructions, drawings, and plenty of your patience.
D) Im gonna need a screwdriver??? But I'm out of vodka.
Or anywhere in between is fine too.