My original user’s manual that came with my Contax IIa is interesting in that unlike so many others there is no advice to send camera to factory authorized service but only to qualified repairman. Sent my cameras to highly recommended repairman who fixed my Medalist. IIa shutter has a very good reputation for being robust without weakness of aging silk tapes.
Very tough well made cameras accompanied by excellent lenses, and although I like to use mine, they are not as ergonomic as the various Leica III models.