Meter woes

ditto1958

Well-Known Member
I just got a(nother) new OM-1n. This makes 3 OM-1's. I'm actually trying to find a good "user" (one that's not too beat up but also not one that's so close to mint that I'd feel guilty about using it). I recently sold the user I did have, only to almost immediately conclude that I had made a big mistake.

My problem is that the ones I have left all seem to have wildly disagreeing meters (unlike the one I sold which seemed to be dead-on accurate). Is this a problem common to the model? Is this something a repair shop can easily adjust?
 

mpve

Member
Hi Mark,

I am not sure if you are aware but the OM1/OM1n needs a battery that is no longer available (a 1,35 Volts Mercury type). If you use a silver/alkaline battery with 1,5 Volts in the camera the meter will be off. This can easily be adjusted: see
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and other sources on the internet (type OM1 battery in Google and you know).

Good luck and..... Do not ditch the camera as it is a marvel!

Regards,

Marc-paul
 

apal

New Member
> [I believe the CDs cells in the meter can deteriorate over the years - > same applies to the manual metering system on the OM2. My OM1 is now off > by about 2 stops. I'm sure the meters could be recalibrated but how > accurate they would then be, and how long the new calibration would be > good for, I don't know.]
 

ditto1958

Well-Known Member
Re: Battery problem. I have purchased two OM-1's which came with 1.5v alkaline batteries. I use either with a Wein Cell, or a 675 zinc air hearing aid battery instead.

Don't worry, I won't ditch the cameras!
 

gjames52

Well-Known Member
[I believe the CDs cells in the meter can deteriorate over the years - > same applies to the manual metering system on the OM2. My OM1 is now off >

Is there any definitive information on these beliefs?

I know there are exceptions but the original transistor is still working and diodes are essentially 1/2 of a transistor.

I have two Cd's one 45 years old and a year or so ago Gossen told me that the Cd cells don't fail, the meters just need to be cleaned and my 36 year old Contaflex still works too. My 25 year old OM2N is still on the money. I don't believe that silicon blue cells fail unless overheated.

Best Regards:

Gilbert
 

apal

New Member
> [John Hermanson at Camtech refers to the CdS cells 'going bad' or becoming > 'non-linear', but stresses that the problem is rare. Others suggest the > cause may be moisture leaking past the epoxy the cadmium sulphide is > sealed in, or simply the epoxy darkening. See zuiko.sls site for numerous > ex&les. The CdS cell is a photoresistor, not a transistor or diode.

The OM2 and OM2n each have two metering circuits, one with silicon blue cells (used for auto metering) which do not suffer from the same problem as far as I know. The other circuit, which moves the needle in the viewfinder, is virtually the same as in the OM1. So it is just as liable to develop 'bad' CdS cells.

Best wishes]
 
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