RZ67 110mm Lens: Broken Diaphragm Pin and Shutter Replacement
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
This Mamiya RZ67 110mm lens came into the shop with a diaphragm that did not work. The issue was straightforward, the pin on the diaphragm control ring had snapped off. Not surprising as this lens had suffered some trauma: a cracked front filter, damaged lens lock ring and several loose internal screws. While the diaphragm control ring could be replaced, that would take a complete disassembly of the shutter down to the diaphragm blades, a lot of labor. So, I decided to replace the shutter, less labor but higher parts cost so it balanced out.
Photo three shows the new shutter on top with the broken one below it. If you look carefully, you can see the silver pin is missing on the black diaphragm control lever on the bottom shutter.
Photo four is of both shutters with the new one on the left. The shutters look slightly different due to a revised version but both operate identically.
Probably the most time consuming aspect of this repair is removing the old contact pins from the shutter to install on the new cable. Photo five shows the old shutter in a vise right before I start de-soldering the connections. You have to be careful with putting the old contact pins on the new cable because if the pins get too hot (either when de-soldering or re-soldering) they will melt the plastic contact strip and cause a problem. After re-soldering, all connections are checked under magnification to make sure all is well as seen in photo six.
Unlike the RB67, there were thirteen different replacement shutters made for the various RZ lenses. And, disassembly of the RZ lenses can be a little trickier, so I imagine I’d rather repair RB lenses!
