What battery Minolta?

[oftheherd]

I recently acquired a Minolta SRT 101 in excellent shape. It does need a battery for the light meter. It had a PX 13. I don't even know what that is. Is that one of the old mercury batteries? Is that a modern battery and one that will allow the meter to function correctly?

At any rate, what battery should I be using? A PX 13, some flavor of wein? What say those of you who are currently using those fine old cameras?

[Chriscrawfordphoto]

Yes, the SRT-101 took a mercury battery. i have one of these cameras and the choices are the Wein Cell or the CRIS adpater that lets you use a modern silver-oxide battery. I put a Wein in mine to test it when i first got it and when it died i never bought another since I usually use a handheld meter with old cameras like that. But the Wein worked well

[rover]

I guess it is an easy adjustment to modify the meter to work properly with a modern battery. If you send it in for a CLA ask that this be done. There are also instruction somewhere on line on how to do this yourself. I don't remember where, never bookedmarked it, too many thumbs.

[oftheherd]

Thanks ChrisCrawfordPhoto and Rover. I guess then it was a 1.5 volt battery or was it a 1.3?

[cmedin]

The original battery was a 1.35 volt mercury one. You can modify the metering circuit (easier than it sounds) with a Schottky diode to have it accept modern 1.5 volt batteries.

[ltketch]

oftheherd, have you joined the manual minolta group (http://tech.groups.yahoo.com/group/Minolta-Manual-Focus/)? There is heaps of info, including a download that explains how to adjust the SR-T's for 1.5v batteries!

[venchka]

Wein cell. Works in my QL17, EF, M5 (two) and Gossen Luna-Pro. All of these originally used 1.35 mercury batteries. Just remember to switch the meter off when not in use.

[colyn]

I soldered a schotkky diode inline to reduce battery voltage and use a 357 silver oxide battery with rubber "O" ring as a spacer.

[oftheherd]

Thanks all. Especially the link to the manual Minolta site. Interesting.

[Seele]

The diode method has been mentioned and quoted over and again on various websites; I gave it a try and found the response to be non-linear. I shall send the recalibration method files to my camera technician and see if it is a more viable method.

Some years ago at Darkroom & Creative Camera Techniques (now Photo Techniques) a plan for building an active voltage stabilizer circuit was described which gives even greater stability than relying on the output voltage of the mercury battery. I will take another look at it and see if it can be used somehow.