I black marked the center of the viewing window in order to see the rangefinder spot and the rangefinder is working except for the fact that I see a horizontally positioned ghost image. Now I realize that the bright-line frame is also seen twice with a horizontal shift. #1 pivoting mirror o.k. #2 double-sided mirror with horizontal plain glass mask #3 plain glass with square metal piece glued on each side, this has round opening in the center
to the left of #3 is the traditional semi-reflector. I suspect that the metal masks on #3 are not properly aligned. ANY ideas ??
problem solved ! the previous owner did some extensive cleaning of the beam splitter (semitransparent mirror) and removed the coating, the framelines were reflected on the two surfaces of the beam splitter resulting in a double image.
The beam splitter of a junk Petri 7 works perfectly after cutting it to the right size :-)