Problem:
“The internal filters are stuck, the knob “Farbgläser” can not be turned by hand.” The optic had been opened before, probably by the previous owner. He also painted the 12 x 60 in Dutch army green with a witches broom. All lenses and prisms however are in excellent condition and the view is crystal clear. It has the original Zeiss case, which is fortunately untouched, complete and holds the little key for adjusting the reticule. So the decision to repair the filtersystem and let a professional repaint the body on a later date, was a quick one.
The front plate can be removed rather easy. The problem had solved itself, because the filters could rotate now.
To find out what happened the filtersystem was removed.
The glasses were opened by the previous owner. He had dislocated two screws of the frontpanel. One was placed on the wrong spot and was to long for this position. It jammed the toothed wheel. Someone forced the knob later, but nothing was broken in this action.
After a good clean, some grease and a prudent air blow, the 12 x 60 was mechanically and optically as new. The repaint project will follow.