Ok call me a crank, but I like the older mechanical equipment like Nikon F2's and Canon F1's etc. None of that wizzy stuff for me. And I'm not even going to get into the MF and LF gear I have. All mechanical. Still works when the battery goes dead. Now try that with the new elecronic marvels.
Anyway I digress, one of the disadvantages of using this old stuff is that they were designed to operate with 1.35v mercury batteries. Something our enviromnent I guess really doesn't need in the landfills. The new replacement batteries are 1.5v. Hence incorrect readings.
I did some searching on the net and Photo.net and found the MR-9 appliance as well as the Wein battery alternatives. I also found some had used a 675 battery with washers to replace the 625.
I meandered over to my local Radio Shack with my old Gossen LunaPro and proceeded to try different battery combinations. Tried the 675's and when I hit the battery check it was well short of the required spot. Funny considering they are 1.4v batteries (needs 2). Horsed around with other batteries and finally settled on the 625's at 1.5v each.
When I did a battery check it was just over the sweet spot. I then compared results once I got home to my Pentax Spotmeter and a Zeiss meter. It was only about 3/4 of a stop high. That's an easy compensation to live with.
Now to my question. I would rather get inside this little beasty and rework the wheatstone bridge or whatever it uses with new resistor values so it will read accurately with the newer batteries. Does anyone have a repair manual or wiring diagram they can share with me that would allow me to accomplish this?
The meter is not worth taking it into a repair shop to do something I can do myself.
Any help would be greatly appreciated. Also does anyone have any first hand experience with these MR-9 adapter thingies? I've heard pros and cons on them.