I have one of these too. Mine uses a mercury battery which is now obsolete, however it is my contention that it may be replaced with a silver/zinc of similar physical size. The Spotmatic employs a needle match system which normally consists of a bridge-circuite. These circuits only need a source of current. The exact voltage may not be absolutely required. A few tests could be in order. I base this on a long-time familiarity with similar instrumentation utilizing Wheatstone bridge circuitry and some recent experiments with other meters using similar technology.
Originally Posted by Jorge Oliveira
Truly, dr bob.
P.S. You do not _have_ to have a meter to use this camera (and many others). The Pentax Asahi Spotmatic is a very good camera. I still us mine.