YouTube has some repairs but its not real difficult if you take your time, open it up and pay close attention before removing "anything". Quick pic of dismantling so know orientation of how it goes back together. Lot of times failures internally are just fouled,dirty grease. Spray out really good with brake cleaner or electrical contact cleaner and reapply grease. Schematics you get with reels are almost impossible to make heads or tails of.
If repairs don't work, toss and get a new one. Probably cheaper than what you would pay someone.