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Olympus OM 1 Lightmeter mechanics and repair


morizklonner

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Hello everybody!

 

This is my first post. I hope the community here can help me out, as I had to find out that the classic camera repair forum is no longer online.

 

Some Sears ago I received an Olympus OM 1 from the father of my best friend from Japan. It is a rather olo one, still without the MD baseplate. Unfortunately the meter was broken, and I thought it could not be fixes.

 

A few weeks ago I found out that it is a broken battery cable most of the times, and of course that was the problem of the dead meter.

 

I fixed the cable, soldered in a Schottky Diode with appropriate sr44 battery, removed the degraded pentaprism foam and everything seemed to work.

 

However, the meter is is ab two stops off compard to my other slr's (Canon F1 new, Canon AE1, Zenit 12 XP), the needle is too low. This seems to be a linear problem, regardless of low or bright light.

 

I did a lot of research, reading every thread on every forum, studying the repair manual and the articles I could find.

 

I checked the zero point at B, F8, ISO 1600, which was fine, I removed the mirror box, and made sure the coupling strings are on their pulleys, which they were.

However, the excentric stop for the cam cear did not touch said part, and the pulley of the spring in the back is iot even close to 1mm distance to the other pulley when the connecting ring is turned to its full extend, as mentioned in the repair manual.

 

Is Is possible for the string to stretch over time? Is it possible to change the string? If yes, what is thetrole of the cam gear and what does a change in the chord controll disc do in the whole system? Are the coupling chords set up right as long as the zero point is finde? Should I just change the zero point until I have right metering?

 

My guess is a mechanical problem, as an electrical or anfaulty cds cell should result in non linlinear problems, right?

 

I would be very happy to receive any help.

And Af possible fix it by myself, unless anybody could suggest an Olympus repair shop in central Europe or UK (I'd love love to send it to John Hermanson, but bhipping would be be super expensive and I fear customs fee)

 

Thanks a lot and best regards

 

Moriz

 

Vienna, Austria

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Moriz,

 

I currently have 6 OM-1 bodies and 3 OM-2 bodies. I've had all of them serviced by John Hermanson at www.zuikio.com. I see that you are in Austria - it is worth the hassles of shipping your early OM-1 to the USA to have John work on it. I'd register the camera with Austrian customs before shipping to avoid the duties on it's return.

 

John now works part-time on OM repairs but he is absolutely the best person to sort out OM-1 issues. John will mod the meter circuit and calibrate it to work properly with a 1.5v silver oxide battery.

 

See:

 

www.zuiko.com

 

Highly reccomended!

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I cannot imagine the braided nylon coupling strings in the meter stretching.

 

Looking inside the lens mount, the round roller just past 12 O'clock should be barely visible, resting against the outer surface of the coupling ring's cam. If not, there is a mechanical fault in the mechanism. (Normal orientation shown in image below.)

 

IMG_0821.JPG.05d19b3c2b1ca619e72fa4d0b3ad8e0d.JPG

 

There are many possible problems, far too intricate to describe. But realize that the plastic frame that holds the meter assembly in place (necessary for reliable operation) began to craze and fracture decades ago, to the point where repair today is questionable. Still, there may be a chance if someone familiar with early OM-1's is able and willing to check it out.

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  • 4 months later...

Thank you all for replying, and sorry for me not doing so!

I did tinker with the OM 1 a bit by myself, but had it then serviced by OM-Doktor in Hamburg, also a factory trained service guy. He did a great job. But in fact I think he just shifted the zero-point of the meter, and now it does meter fine again.

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Hi,

Good shout with the zero point and suspect your right, nearly all early OM1's I've looked at mechanically zero at 'B' ASA1600 and f\8 (For context I use a 50mm f1.8), this is a very easy check for most people to see whats occurring and the needle should be nice and central in the viewfinder, if its a little out its also fairly easy to make a fine adjustment but you do need to remove the top plate again for that.

 

@ Crumbo - I would also agree and would emphasis that these strings do not really stretch, I've never seen it, yes they can come unstuck from the speed sensing ring or the meter pully but this is usually a symptom and not a root cause.

 

Glad you up and running and enjoying the OM1......

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