Leicameter MR-4 Battery

[cassel]

Just picked up a MR-4 meter for my Leica M4-P. It looks to be in good shape but I'm having trouble with batteries. It was sold to me with the MR9 adapter that allows me to use the 386 (SR43) battery...it's supposed to convert the voltage to 1.35 and makes it the right size. The first 386 battery I tried lasted about 3 days. Seemed to work ok, but this morning it's dead. The battery test button is erratic- jumps around and sometimes settles on the correct spot- sometimes not. I put another-different brand-new 386 in it this morning and it seems to be accurate again. The test button is still acting strange. I also have a Varta v625u that I tried and it is too high a voltage- but it does fit and works OK.

What should I do? Accept that the test button is not working right but the meter is OK otherwise? Try the new battery for a couple of days? Take it back and get it repaired or refunded? Send it to Quality Light Metric? Buy another one? Buy a Wein 625 cell?

 

[anjoca76]

I have one, and I have the same problems. It's accurate with a new battery, but that only lasts a couple of days. Unfortunately, I believe the only options are to live with it the way you have been, or send it to be repaired. I like mine a lot, both aesthetically and functionally, when it functions, but I can't justify the cost of repair for a 50-year-old meter.

 

[cassel]

OK--I just read about the ZERO needle adjustment. I checked the needle without a battery and it was way off...so I used a small screwdriver to make the adjustment and it now reads properly on the battery test AND seems accurate on meter readings. Now- hopefully the battery won't fail in a couple of days!

EDIT: Battery test function still not consistent.

 

[cassel]

Just got back some shot film that used the meter as a guide. The pictures were pretty much all under-exposed. Disappointing, but it makes sense because the meter had not been properly "zeroed out". hopefully the next roll will be better.

Also, it may have been a stupid move, but a bought a 2nd MR4 meter. It was pretty cheap and it works (supposedly). I will try it out when it arrives🙄

 

[cassel]

UPDATE: After doing more research, I learned that the MR-9 adapter does not work without modification in the MR-4 Leicameter! It will need to be sent back to the manufacturer- Kanto- in Japan. The cost is 4,200 yen. I also ordered some Wein cells...

 

[MartinP]

I am using an MR9 adapter in another device (Rollei 35S) which originally used a mercury cell and it seems ok without recalibration. Note that the adapter will be a little deeper than the original cell and will stress the plastic battery-door on the meter.

My solution for the Leicameter was to buy one Wein cell and then re-use the spacing washer to mount hearing-aid zinc-air batteries. These have the appropriate, very flat, discharge voltage-curve and are within a few millivolts of the mercury cell voltage. As the drain with the meter is less than a hearing-aid you can open just one of the air-holes on the battery, to reduce the rate at which the cell dries out - they last longer than six months for me (but NL is cool and damp).

 

[hendriphile]

In my experience the Wein cell has been good for several months, then it's good to have a spare one on hand while regularly checking the battery strength.

 

[Beemermark]

The MR-4 meter works well with a silver oxide battery, so do most other meters and cameras. Generally only real cheap cameras from the '70's have problems using silver oxide. Throw the adapter away, put a silver oxide battery in, and calibrate the needle with the adjusting screw using the sunny 16 rule and you're good to go.

I've been using silver oxide batteries for at least 20 years in different MR-4 meters and have never had a problem (not even with Kodachrome 32). Ditto for most cameras. Some camera well handle the slightly higher voltage without a problem, others you need to use the ISO dial to get it perfect.

http://support.radioshack.com/support_tutorials/batteries/bt-siox-main.htm

 

[cassel]

Now I have two of these plus a supply of Wein 1.35V cells. The new one works fine- matches my Luna Pro SBC right on the money. I will try out the old one with a Wein next...but I suspect dirty contacts/faulty test circuit.

 

[Jerevan]

Just curious as I have an MR-4 from 1983 with a Cris-Cam (MR9) adapter in it - why does it have to be modified?

 

[cassel]

It sits too loosely in the battery compartment...Kanto sent me a picture of the modified meter to fit the MR9

BTW I just tested the 1st MR4 meter with a wein cell and it is about 2.5 stops off from my Luna Pro and my other MR4. Plus the battery check function is still erratic.

 

[Jerevan]

Aha - I see. I thought it had something to do with the voltage or electronics. Thanks! 🙂

Thus far (two rolls) my own MR-4 seems to be working well enough for b/w.

 

[cassel]

Just got off the phone with Doug at Camera Clinic in Shoreline (north of Seattle) where I bought the first meter. He wants me to bring it in for him to have a look at it. Not gonna make it there today, closes at 2pm, but in the meantime I will test the 2nd meter.🙄

 

[cassel]

Took my meter to Doug last Saturday and he will adjust it to be a bit more accurate. I just got back a test roll that uses the old meter and the new meter: the results were confusing! Exposure looked ok, pictures that I thought would be underexposed looked ok, just a bit dark. Not that different from shots with the new meter. Negs look a bit thin so I'm guessing the lab made corrections. Hopefully I'm not wasting time getting it adjusted. I know that the meter was NOT agreeing with my known accurate Luna pro...

 

[cassel]

Got my meter back from Camera Clinic...it is exactly one stop off from my other meter. I know that my Luna Pro agrees with the second meter. Oh well, I will continue to test and figure out how to best use the meters. One irritating habit of the second meter is that the film speed setting gets bumped/changed going in and out of the bag...it's made me miss a few shots.