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fidget
02-09-2009, 07:20
Although I had been cured from GAS for at least a month, i had to have a pop at a 35RC on thE bay.
This is the second I've ever had, the first had too much corrosion round the meter and battery compartment for my clean-up skills.

This new one seems to work. At short test film went through OK, no light leaks seen.

I have made up a spacer to allow a fairly ordinary 675 alkaline cell to fit. I understand that mercury cells were specified for it, but is this one of those cameras with a metering system that is not upset by a different voltage cell?

Dave...

wallace
02-09-2009, 07:54
Congratulations, you bought a fantastic camera. The correct battery would be the PX625 (1,35V). I am lucky to own a couple of the orig. mercury batteries but also succeded in using hearing aid batteries (which do not last very long).
There are adapters available, so you could use normal silver batteries (1,5V).
Here's everything you need to know:

http://rick_oleson.tripod.com/batt_adapt_us.pdf

Thomas (wallace)

fidget
02-09-2009, 23:42
Thanks for the link, some very useful info there.
I guess that the first thing to do is to try the metering with a zinc-air cell and compare it to an alkaline cell. Maybe the 35RC metering is within a bridge circuit and is not sensitive to voltage variations.

Dave

kuvvy
02-10-2009, 01:18
Hi Dave,
Not seen you since the RFF meet in Manchester last year. I have a couple of the original 625 mercury type cells if you're interested. PM sent.

fidget
02-10-2009, 09:19
Hi Dave,
Not seen you since the RFF meet in Manchester last year. I have a couple of the original 625 mercury type cells if you're interested. PM sent.

Thanks Paul, Seems a long time since Manchester RFFers were out in the heat!

Thanks for the offer too. I am fascinated by the idea of using the Shottky diodes to drop the voltage of a modern cell. I'm sure I have/had a bag full of them. I must check, if so I will try that.
Fancy a meet and a chat anyway?
It's too dark for evening photos on the street, but I bet they would let us into the Weatherspoons pub, Hmmmm.
I'm working at the moment, will get back to you soon.

Dave...

fidget
02-11-2009, 04:29
I took a zinc-air hearing aid battery (675ZA) and compared the meter readings to those with the Alkaline cell fitted. At least at a reading of f4 at 1/125th, both are identical.

I guess that the metering circuit in the 35RC incorporates a bridge, making it far less sensitive to voltage variations between different types of cells and gradual battery run-down. Very nice, a proper metering circuit!

Dave

Eugen Mezei
02-11-2009, 18:33
I took a zinc-air hearing aid battery (675ZA) and compared the meter readings to those with the Alkaline cell fitted. At least at a reading of f4 at 1/125th, both are identical.


They are today. Do you want to redo the test tomorrow to? Or in an hour, or in half an hour? As alkaline has not the flat discharging curve of mercuries, you would have other results when comparing again.


I guess that the metering circuit in the 35RC incorporates a bridge, making it far less sensitive to voltage variations between different types of cells and gradual battery run-down. Very nice, a proper metering circuit!

Dave

No, it has not.
Do yourself a favor and buy a mercury cell. It will last you at least 10 years in the 35RC without all the hassle you have with adaptors, alkalines or also Zn-air batteries. Just drop the mercury in and don't worry that it will be empty when you grab the camera from the drawer let's say in 2 years or even a month. Just go out and shot, without fearing emptied batteries, bad exposure, etc.

Contact me directly for _fresh_ mercury cells. (As some other list members already did.)

Greetings,

Eugen