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Re: [OM] Fixing a sticky 50/1.8 was, One more lens to look for

Subject: Re: [OM] Fixing a sticky 50/1.8 was, One more lens to look for
From: John Hermanson <omtech1@xxxxxxxxxxx>
Date: Mon, 22 Jul 2013 06:54:49 -0400
Yes, it could mean that only the back rings are oil (now).

___________________________________
John Hermanson  |   CPS, Inc.
21 South Ln., Huntington NY 11743
www.zuiko.com  | omtech1@xxxxxxxxxxx
Olympus OM Service since 1977


On 7/20/2013 6:22 PM, Chuck Norcutt wrote:
> A sticky diaphragm usually means that the grease from the helical has
> broken down into a thick oil.  It flows along inside the lens until it
> gets to the diaphragm blades.  The thick oil causes the blades to be
> sticky.  Then can be just sluggish or frozen open or closed.
>
> Since the blades are snappy when using the camera's activation lever
> (the inner tab) the blades do not have oil on them which is very good
> news.  Using the DOF tab, however, does nothing other then press on the
> same aperture lever used by the camera but inside the lens rather than
> outside.  If you watch the inner tab while you press the DOF tab you
> will see that both move together.
>
> Since only the DOF tab operates sluggishly it means that the problem is
> only in that linkage.  The DOF tab presses on a semi-circular ring that
> is about half the circumference of the lens.  It pivots on a single
> screw not far from where the DOF tab contacts the ring.  Sluggish
> operation would seem to mean a loose screw, dirt or maybe even oil on
> the ring.  In other words it likely needs a screw tightened or simple
> cleaning.  Fortunately, it's very easy to access.  I copied some repair
> text from an old message from Don Gaiken...
> -----------------------------------------------------------------------
> ...remove the three silver screws from the mount.  The rear mount will
> just slide off.  There are two tabs sticking out of the inside of the
> mount.  One goes into a fork attached to the aperture's cam ring.  The
> other actuates the aperture - it's spring loaded.  To reassemble, just
> align the free tab (the one that's not spring loaded) so it will go
> between the legs of the fork, then turn the mount so the screw holes
> line up.  Turning the aperture ring on the front should move the tab
> sticking out of the back of the lens both ways.  If it only goes one
> way, try again - you've missed the fork.  And when you move the aperture
> lever on the back of the lens, the diaphragm should close - if not, try
> again - you're on the wrong side of the lever!
> ------------------------------------------------------------------------
>
> Chuck Norcutt
>
>
> On 7/17/2013 1:33 PM, Vick Ko wrote:
>> By the way, my iris is "snappy" if I use the inner tab (the one the
>> camera body activates) but sticky if I use the user DOF tab.
>>
>> Is that the characteristic failure mode?
>>
>> Vick
>>
>>
>>
>> hOn 17/07/2013 1:23 PM, Vick Ko wrote:
>>> My 50/1.8:
>>>
>>> - “Japan" on the front ring
>>> - full lettering is " OLYMPUS OM-SYSTEM ZUIKO MC AUTO-S 1:1.8 f=50mm
>>> Japan " , caps and lower case as presented
>>> - all black front
>>> - sn 2756466 on the rear-most silver ring that has the DOF scale
>>>
>>> So which version do I have? I'm thinking Type 3.
>>>
>>>
>>> regards
>>> Vick
>>
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