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Re: [OM] 20mm f/3.5 Zuiko Macro with stuck diaphragm

Subject: Re: [OM] 20mm f/3.5 Zuiko Macro with stuck diaphragm
From: Fernando Gonzalez Gentile <fgnzalez@xxxxxxxxxxxxx>
Date: Tue, 25 Nov 2008 11:31:06 -0300
Same warning.

The most reputed repairman in Montevideo, told me more than once that is 
not a common grease.
My 21/3,5 suffers from the opposite illness, fortunately not in the 
aperture ring but in the focusing ring: it is rather loose, 'though I 
can perfectly use the Zuiko. Asked more than once if he could fix this 
almost non-issue, but he refused; alleging that kind of lubricant was 
very difficult to find here in town. I suppose both the aperture ring 
and focusing ring use the same type of lubricant.

FWIW

Fernando.

Chuck Norcutt wrote:
> A warning that I'm overstepping my bounds here but, from looking at the 
> parts diagram, I would agree that it looks as though the aperture ring 
> should simply slide off.  If the grease has solidified to the point of 
> preventing the ring from turning (as Mark's note hypothesized) then I 
> would not be at all surprised that it's that same solidified grease 
> that's acting as a glue between the two parts and also preventing you 
> from sliding it off as well as turning it.
>
> If it were me I would very gradually feed some drops of a solvent such 
> as Ronsonol lighter fluid around the inner diameter of the aperture ring 
> and perhaps on its back face.  Also maybe a drop or two in the groove 
> that appears to slide over the actuating pin Mark mentions.  Just don't 
> use so much that it ends up dripping and running inside the lens.
>
> If the grease is totally dried out and has evaporated off all of its 
> volatile components I'm not sure warming can help much.  It probably 
> does need a solvent to loosen it up.
>
> On the other hand I think this is a very expensive piece of glass... so 
> ignore what I just said.  :-)
>
> Chuck Norcutt
>
> Alan Wood wrote:
>   
>> In 2001, Mark Dapoz kindly provided some advice:
>>
>> Chances are that the grease around the aperture ring has solidified
>> and is preventing it from turning.  Use a rubber stopper to twist the
>> front part of the lens off, it's just a big retaining ring.  The
>> aperture ring should then easily come off.  You will then see a
>> little pin sticking out from the barrel.  Try moving that pin, it
>> should move freely and close the aperture.  If it doesn't then you
>> have other problems and it's best to get the lens CLA'd.  If it does
>> move freely, just clean up the grease on the aperture ring and
>> re-lube it using an appropriate grease.
>>
>> ----------
>>
>> It has taken me 7 years, but I have finally managed to unscrew the
>> front ring (the one that says ZUIKO MACRO etc.).  Now I cannot get
>> any further.  The aperture ring (the first knurled ring) will not
>> come off.  I have tried gently warming it.
>>
>> Please does anyone have any suggestions for loosening it?  Maybe a
>> solvent?
>>
>> Thank you
>>
>> Alan Wood http://www.alanwood.net (Unicode, special characters,
>> pesticide names)
>>
>>
>> ------------------------------------------------------------------------
>>     


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