How can I test the light meter mechanical drive on an OM-1(n)?
Most of the string pulley light meter mechanisms of the OM-1 stay calibrated when removing the lens mounting ring, but there are some gear differential/string mechanisms that can give the repair person fits when moved. Good mechanical aptitude fails working on these cameras. While there is a minor mechanical adjustment directly on the meter case, it’s not enough to compensate for the differential geared light meter movement when the gear assembly is disturbed. I saw a reference that saved the day for these OM-1s. The secret is to set the camera at ASA 1600, f8, and “bulb”. With those settings and the light meter power OFF, the meter needle should be at the zero position. This mechanical string pulley/differential gearing no power meter setting works for all the OM-1 and (n)s I have seen to date. Using those settings gives an important reference point, the remainder for repair becomes just challenging mechanical aptitude and dexterity. This setting test is also useful to differentiate b
