lukx
Well-known
In case someone else stumbles across the issue of a stuck rangefinder on a IIa or IIIa, here is an image that illustrates its function.
The brass part center left is the actual rangefinder cam that drives the orientation of the rf patch based on the position of the focusing mount. The little arm that lies against it transfers the movement and swivels the little glass lens accordingly. It connects to some springs that lie underneath the little brass plate at the right. When debris or gunked up grease is trapped in there, the little arm won‘t spring back then the focus is turned, leaving the rangefinder in position. Adding some lighter fluid and careful movement of the parts should free things up…
