Mamiya 645 1000S: Corroded Battery Compartment and Broken Latch
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
This 645 1000s came into the shop for the typical slow film counter return and shutter calibration (I have documented the counter return issue on a previous post).I noticed that the battery compartment door was taped closed and upon examination found the latch (plastic) to be damaged. Also, the battery compartment had deep corrosion on the contacts as seen in photo three. Although this corrosion could be cleaned off, with this much damage to the plating, I chose to replace the battery box.
Taking the bottom cover off the camera gives me a chance to show the different styles in bottoms and battery covers.
When the Mamiya 645 was introduced in 1975, it had a round button that you would turn to open the battery door. When the Mamiya 645 1000s was introduced in 1976, Mamiya redesigned the bottom cover and the battery latch because the original latch did not leave room for the self timer used in the 1000s.
Photo four shows the original bottom cover on the left and the new style introduced with the 1000s in 1976 on the right. Photo five shows the underside of the bottom cover in both models, with the large latch mechanism of the original style on the left. Photo six shows the self timer assembly of the 1000s in the foreground so you can see how the original latch assembly would not fit in the space now used for the self timer.
The 645 1000s and the original 645 were produced concurrently, but only the 1000s had the new style bottom cover until June of 1981 when Mamiya used the new style in all versions of the 645. Just a note: in March of 1981, Mamiya changed the material of the bottom cover from metal to “GF Reinforced Plastic”
