Mamiya 645 Super/Pro: Battery Contacts Bent by New Battery Style
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
Another post about new style form factors on batteries causing problems for Mamiya cameras, this time the 645 Super/Pro/ProTL. I have done several on the alkaline batteries for the Mamiya 7II, so now the 645 series gets a mention.
This week I had three Mamiya 645 bodies (Super/Pro/ProTL) come into the shop with the same issue, a bent or missing positive battery contact. This did not seem to be a coincidence.
I was able to straighten two of the battery contacts, the third camera had the contact totally gone, broken off. I imagine this was because of a straightening attempt.
On close examination of the batteries (6 volt alkaline) I found that the older batteries (at least Duracell), had a negative contact that protruded about two millimeters past the body of the battery. On a newer alkaline battery that I have, the negative contact was actually recessed about one millimeter in the casing. Photo two shows the negative terminal on each battery, the newer one on the right.
While this small difference is not usually a problem since the battery contacts are spring steel, if one of the newer style batteries is inserted wrong in the battery box, it will not come out easily as the downward facing positive contact has a sharp edge and will contact the casing of the battery when it is attempted to be removed. When force is applied, the battery contact will bend or worse. Photo three shows the contact.
While the 645 Super battery box is not that difficult to replace, the 645 Pro and ProTL have a battery box that is very time consuming to replace as it is soldered into the back of the circuit board. In fact, if the contact is damaged on the Pro/ProTL and needs replacing, that might be EOL for the camera due to costs to replace it.
