RZ67: Diagnosing Shutter Not Releasing, Mechanical or Electrical
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
A very common issue with the Mamiya RZ67 is that the shutter does not release. This is usually caused by the mirror not releasing and can be a mechanical or electronic issue, the first thing to do is to determine which it is.
For testing, put the camera mode switch on M (for multiple) and the shutter release button on the orange setting (for mechanical release). Install a lens, take off the film back and release the shutter with the shutter speed set on a slow speed, maybe 1/4 second while looking through the back of the camera. If you see the shutter operate at the mechanical speed of 1/400 then you have an electrical issue. If you only hear a light click but no shutter opening then you have a mechanical problem.
While electrical issues can be caused by several things, the most likely is a bad capacitor and/or diode. On disassembly for a recent repair, I noticed corrosion on the circuit on the top side of the board by the capacitor leads. Strong clue that the capacitor is bad (photo three). After removal, photo four shows one of the capacitors and the leaking of its internals. After capacitor replacements, the camera is now working perfectly as shown in the video.
For a mechanical issue with the mirror not releasing, things are a bit more complicated as the problem would be caused by the mirror cocking arm and/or cocking shaft. Mamiya made several changes to this system and improved the material that was causing failures in early models. The RZ67 cocking system not only had to charge the mirror and shutter but also needed to advance the film so it was called on for a lot of purposes and had more strain than the RB67.
While repairs on the RZ67 may at times equal used replacement cost these days, keep in mind that all of these examples are getting ready to fail so your replacement model, unless serviced in the last decade, may soon need a repair.
