I bought a couple of Exaktas from the estate of the late Jim Upton who was a competent repairman and replaced the shutter curtains.
A common fault with Exaktas is shutter curtain pinholes. I dealt with this by diluting 'Plasti-dip' as sold for dipping tool handles and carefully painting the shutter curtains. This salvaged a beautiful 'embossed' nameplate VXII acquired at a jumble sale.
Mark