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OM 1 battery conversion

jgoody

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I am about to send my beloved OM1n (bought new -- way back when) to John Hermanson for an overdue CLA. I have the little CHRIS MR 9 adapter to modern battery in it currently, which works well. My question is whether there is any downside to having John make the internal conversion vs keeping the adapter. Thoughts?
 
If you let John do the conversion, your OM-1 will not be in original spec.
Personally I wouldn't allow him to do it.
 
Ricardo Miranda said:
If you let John do the conversion, your OM-1 will not be in original spec.
Personally I wouldn't allow him to do it.
Click to expand...
I don't understand. Out of spec in what way, not able to use mercury cells anymore? I've had three OM-1's (2xOM-1n, 1xOM-1) converted by John during CLAs and am now using them perfectly with silver cells. John does very fine work. Highly recommended!
 
Well, some people have a very conservative stand about "original state". For old cars for instance that would imply still having the original manufacturers paint layer, not a repaint with same colour.
Or rejecting to fit an oldtimer with safety belts.

See Ricardo's remark in this context.

You would have to decide between a perfect user-camera and a perfect show-camera.
 
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As you will never be able to get mercury cells again, there is no point in having it set up for them when it could use silver oxide cells instead.


Steve.
 
I'm sure he does enough of a good job.
The thing is any battery conversion, even the one he does by putting a diode in the circuit, is a modification of the original specification. the response of the meter and high and low lights will be slightly different.
You can read all the mumbo jumbo here: http://olympus.dementix.org/Hardware/PDFs/OM1DiodeVer2_1C.pdf

It is far easier to use a Weinn cell or a Zinc-air ZA675. The ZA675 with an O ring to centre is is all what I use and it is cheaper than using a Silver Oxide battery.
 
jgoody said:
I have the little CHRIS MR 9 adapter to modern battery in it currently, which works well.
Click to expand...
So, to not do anything but CLA and continue to use your camera, as is, means you own an "original" plus working unit. The best of both worlds I would think?
 
Steve Smith said:
As you will never be able to get mercury cells again, there is no point in having it set up for them when it could use silver oxide cells instead.


Steve.
Click to expand...
Steve,
See the above. As you see there are other options that don't involve modifying the body.
Another reason not to have it modified is: how on Earth are you going to be able from the outside to know if a body has been modified or not? Unless someone marks it somehow, there is no way to know unless you open the bottom plate or worst the top plate.

Another option is to use a MR9 adapter if you really want to use a Silver battery, but it is expensive.
 
Ozxplorer said:
So, to not do anything but CLA and continue to use your camera, as is, means you own an "original" plus working unit. The best of both worlds I would think?
Click to expand...
Yeap. He already has the MR9 adapter.
 
There are two schools of thought on this in UK. Firstly it is claimed that you cannot easily change the meter callibration, so what they do is open to question. Secondly I have used a few cameras and seperate meters which were manufactured to be used with Mercury Batteries but have used the 1.5v silver oxide type. (Minolta SRT, Pentax Spotmatic and Olympus OM1n and an Olympus SP compact rangefinder type). There was no problem with exposure either under or over and the cameras didn't complain so really is there a need to change? If you feel it is absolutely necessary just alter the film speed by 1 third. For example, instead of ISO 125 set it at 160 instead, but really it isn't needed.
 
Just use the external meter...
 
BMbikerider said:
There are two schools of thought on this in UK. Firstly it is claimed that you cannot easily change the meter callibration, so what they do is open to question.
Click to expand...

It's no mystery. A Schottky diode is put in series with the cell to drop about 0.2 volts.


Steve.
 
Actually its not a big mod otherwise they may be charging more for doing it.
 
Ricardo, then I got you wrong.
But still then, to my understanding, the issue would only be chosing the right diode, based on the original meter-current.
But I shall look into that pdf.
 
Ricardo Miranda said:
It is far easier to use a Weinn cell or a Zinc-air ZA675. The ZA675 with an O ring to centre is is all what I use and it is cheaper than using a Silver Oxide battery.
Click to expand...
You can put a Zinc-Air ZA675 directly into the battery compartment? No need for conversion?
 
The Spotmatic has a bridge circuit so it isn't affected by small variations in voltage.
 
KidA said:
You can put a Zinc-Air ZA675 directly into the battery compartment? No need for conversion?
Click to expand...
Correct. You only need a plumbers Oring to keep it centred.
The ZA675 is a fraction shorter than a PX625, but the spring on the bottom of the chamber will take care of that difference.
 
I find the MR-9 adapters superior because the battery life is longer than the zinc-air cells. The initial investment isn't inexpensive but the battery cost differences aren't enough to make me change.
 
Ricardo Miranda said:
Correct. You only need a plumbers Oring to keep it centred.
The ZA675 is a fraction shorter than a PX625, but the spring on the bottom of the chamber will take care of that difference.
Click to expand...
I guess this would apply to the Oly 35SP? They take the same battery as the OM-1.
 
KidA said:
I guess this would apply to the Oly 35SP? They take the same battery as the OM-1.
Click to expand...
I don't have a 35SP, so had to look at the manual. The battery compartment seems to be identical and so it should work. But, only you would know if your 35SP has a contact for the + side on the side of the chamber. In that case the ZA675 would have to be fitted with a metal ring.
 
If I had one in with John, I would have him modify the circuit. Essentially, what he does is permanent installation of a MR-9 adapter.

When I had an OM-1, I had a MR-9 adapter in it. My other PX13 cameras have Jon Goodman's adapters for ZA 675 hearing aid batteries in them. Both alternatives work well. The MR-9 gives longer life with a more expensive battery. The ZA 675 batteries give shorter life, but they are cheap and widely available.
 
Although I have various cameras that have been modified, the MR9 adapter is really the superior solution. Since the mercury cell was larger than the silver oxide, you will need an o-ring or similar spacer to center the cell. Once you get a mix of modified and unmodified cameras you have to check the meter of each one before use to know what cell to put in it. The MR9 fits both a 357 and a 386 silver cell, so if there are slight variations in the depth of the cell compartment this can be easily accommodated. Especially with my FT's I was emphatic that they not be modified, as to keep them all original.

A note about John, with no intention to cast aspersions. He was never very fast, but since he has gone to part time his service is agonizingly slow. The last camera I sent to him took six months to the day to get back. We are very fortunate to have skilled service people keeping our old cameras alive, but you may want to give serious thought to sending it to KEH or someone else that works on Oly's.
 
I had a diode added to my OM1 MD when a CLA was done earlier in the year so I could use it with 1.5 volt battery. I have a brass adapter that I got off ebay a few years ago that bulks an LR44 sized cell up to PX13 size. The OM1 is the only camera that I had that needed the PX13 battery & it was more convenient for me to get it using the same battery as my other cameras. I also didn't want another camera like the OM2 SP that has a battery drain even when off which was another reason why I didn't want a zinc air solution. I haven't noticed any problems with getting accurate exposures with the recalibrated meter.
 
If it's for "collecting" then don't do the conversion. If it's for active use then do the conversion and calibrate the meter with the new battery.

Incidentally, the conversion is completely reversible.
 
thuggins said:
Once you get a mix of modified and unmodified cameras you have to check the meter of each one before use to know what cell to put in it.
Click to expand...
A mark inside or outside the battery chamber will clarify things.
Of course someone will complain that a mark outside the chamber will spoil the look of the camera.
 
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