I just tore apart a very early Contax IIa BD with a frozen shutter. Looks
like the problem was originally caused by a disk coming loose from the top
of the rangefinder prism and jamming the speed escapement. Looks like
camera than sat unused for years - escapement was totally frozen (soaking
in shot glass of Liquid Wrench for an hour fixed that). This is the second
time I have found a camera jammed by this; the last was a circa 1949 Super
Ikonta B in which the loose disk jammed the advance mechanism.
Question is, what is the function of the disk? It is 12mm in diameter and
was originally glued to the top of the viewfinder block on the prism.
There is also one on the bottom. I don't have a lot of experience with the
post war cameras, but I do not recall seeing this part in a Contax before.
