At least 90 percent of all the Exakta/Exa cameras found on the used camera market today (Ebay, Camera Shows & Dealers) need repairs of one sort or another to perform fully satisfactorily.
The last of the Ihagee Dresden Exaktas, the VX 500, ceased production in 1970, more than 30 years ago. Many, if not most of the Exaktas and Exas encountered today still have the original shutter curtains and lubricants. At the very least, such cameras need a thorough cleaning, lubrication and readjustment (CL&A) in order to operate properly. Many have deteriorated shutter curtains that either are wrinkled or have already developed pinholes in the curtain fabric.
I recommend having the curtains replaced on any used Exakta as the CL&A is included in the price of the curtain replacement job. Doing just a CL&A is false economy; the camera is at least 30 years old.
Many repair facilities claim that they can repair Exaktas satisfactorily. I have examined cameras that were repaired by some very reputable services. You'd be amazed at some of the shoddy work done by even some of the better ones - cameras not cleaned adequately or properly, incorrect fabrics used in (or improperly installed) shutter curtains, etc.
While I haven't personally done camera repairs in some time (due to failing eyesight), I recommend my good friend, Miles Upton, for the repair of Exaktas. He's been doing Exakta repairs for most of his life and thoroughly understands and loves Exaktas. He has recently published a comprehensive manual for repairing Exaktas (see my Exakta Bibliography page) and is working on a sequel covering Exakta lens repair.
Miles can be contacted by visiting his web site Exakta Repair Page by clicking on the banner below.