I've been cleaning up the Praktica MTL3 I purchased on eBay sometime in 2007. It had a quick test at the time, but owing to the fact that the battery had run out I was unable to use the in-camera TTL light meter. As a result I used an old Russian Leningrad 7 light meter, which being a selenium meter, does not require batteries.
The results of the test weren't too bad and I got some passable photographs. The mechanics of the camera are sound, which is not too surprising. the MTL3 might be around 30 years old, but East German Prakticas were built to last, using metal shutters which still give a hefty clunk when operated. The problem with the battery is that since it is a mercury battery (a PX625 1.35V button cell) they aren't produced anymore.
I've found, however, that Maplin are selling what they call a PX625 replacement: the V625 alkaline. It's not necessarily a direct replacement. The PX625 is 1.35V and the V625 is 1.5V. The metering circuit in the MTL3 is a bridge circuit, so I'm pretty confident that this will balance itself and be voltage independent. The best way to find out is to try it, so I've loaded up some 400ISO black and white film (normally use Ilford, but Kodak was on offer) and I'll see what results. If the film comes out over or underexposed, I should be able to knock the ISO setting up (or down) a few stops to compensate.
