The Seikosha-S was actually the second generation of shutters. The really old ones are the Seikosha-MX with speeds to 1/400. Joe Lippincott's out of print 'Care and Repair of Classic Cameras has a section on opening up a Seikosha-S. Enough for basic cleaning. If you need parts you are probably into cannibalizing another shutter. Or if you find a good one, just do a swap.