Mamiya 7 43mm Lens: Shutter Not Cocking From Water Damage
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
Mamiya 7 43mm lens on the bench. This particular example had a mechanical issue with the shutter not cocking. After some external observations and minor disassembly, I found evidence of potential water damage:
1.) interior screw heads had stains and particulate residue.
2.) focus ring rubber has white residue on the surface
Also, a not good sign was that the front and rear element groups were not tightly screwed into the threads and there was evidence that the electrical connections had been de-soldered. Any one of these issues might not give concern to me, but all of them taken together gives me some clues as to the past life of this lens. My client had recently purchased this lens so did not know its history.
Photo four shows the residue on the focus ring rubber and photo five shows a magnified view of some of the white residue that I scraped off the interior of the lens. Certainly appears to be some sort of crystalline material. Since the lens came from area with lots of water (Pacific Ocean), my guess is salt water damage.
At this point I advised my client that I would have to do deeper disassembly to discover the root of the problem and that in worst case, the shutter might need replacing. Rather than spend bench time and expense, it was decided not to pursue the repair any further. I’m very careful anytime I suspect water damage as repairs can be very time consuming and costly in these cases if you want to do them properly.
