O-SP battery?

[Donald Boyd]

I bought another used rangefinder camera from the Salvation Army Thrift Store. What kind of battery does the Olympus SP take?

 

[greyhoundman]

They took the mercury PX625 battery. You can use a 625 alkaline and adjust the exposure with the asa dial. Or take the top off and place a diode in the power wire at the junction block next to the viewfinder.

 

[Solinar]

Zinc Air Cells

Alkaline cells do not provide a constant voltage when in constant use. A new cell will produce 1.5v instead of the required 1.35v when fresh. That voltage will drop in use and you will have no clue as to what it dropped to.

The metering cell of the 35SP is located by the viewfinder and is on when ever the camera is out its case. An alkaline cell will produce a lower voltage within several minutes of use. Also, the drop in output voltage accelerates as the alkaline cell ages.

Zinc Air cells work quite well and have a close to 1.35v output, but have a short live span. The zinc air cell should last a couple of months, during which time its voltage output remains very close to 1.4 volts.

Look for the freshest #675 zinc air hearing aid cell at your pharmacy or drug store. These are a smaller diameter than the original PX625. So, make a collar out of card board or use a rubber o-ring from a hardware store. The o-rings are in the plumbing department.

 

[greyhoundman]

Here is a plan.
Use a S76 battery with your wrapping to take up slack. Then put the diode at the junction. Solves the voltage problem in both departments.
After a dozen or so, no complaints.

 

[Donald Boyd]

I'll try the zink.

 

[Solinar]

The zinc air cells will at least let you know whether the meter is working.

A Schottky diode wired in series to the battery circuit is a permanent fix that allows one to use modern silver oxides. The diode brings down the voltage of the silver oxide closer 1.35 volts. A silver oxide cell will last about a year or longer depending on the amount of use.

If you really like using the camera, then it's a nicer way to go.

 

[John Hermanson]

Diode for PX-13/625 meter

When I convert an Olympus 35SP (or OM-1, 1N) to silver oxide battery (357, 303, G13, SR44W, MS76, KS76) I use the 1N-6263 schotkey diode. You can also use a 1N-34A and probably a host of others. Diode can only go in one way. Banded end should be "pointing" towards the battery (if you know what I mean.) Hope this helps.

John (Olympus tech since 1977) www.zuiko.com

 

[magic823]

Quick question John, I got a OM-2n that about every 5-10 shots the shutter locks open and the mirror is stuck up. Just moving the switch to check clears it. Any ideas? Worth a repair?