Thanks all for the information. I partially disassembled the rangefinder last night and found one of the mirrors had come loose so I re-attached it with a little contact cement and now it works--- sort of. When I rack the bed with the front of the camera with the lens and shutter on it I can look through the eyepiece and line up the two images into one. The problem happens when I backed the bed back the rangefinder linkage had to be moved back manually.

Anyway, I guess I just ahve to live with it until it comes up for CLA and have the repair person have a look and make any adjustments necessary.