The premier shop for F2 repairs is SOVER WONG. I'll send my F2 there when it needs service. However, he is located in the UK.

Another shop that I've used, with excellent service, in the US is FOTOCAMERA REPAIR, Pete Smith, at 30950 S. Military Trail, Suite 15 & 16, Lake Worth FL 33463 Phone 561-433-8434
I've had my F2 cameras serviced by Sover Wong and lenses serviced by Pete Smith. Both repairers do top notch work. Sover's website is worth a visit whether or not you choose to ship to him.