Thanks, Chuck.
Where would a fellow find such a book - Tomosy's Camera Maintenance &
Repair?
Tom Hoefer
Yellowknife, Northwest Territories, Canada
-----Original Message-----
From: Chuck Norcutt <norcutt@xxxxxxxxxxxxx>
To: Tom Hoefer <twhoefer@xxxxxxxxxxxxxx>; Olympus mail list
<olympus@xxxxxxxxxxxxxxx>
Date: February 27, 2000 9:04 AM
Subject: [OM] Locked diaphragm on 75-150
>Tom Hoefer said:
>I just bought a beautiful 75-150 Zuiko on ebay, and darned if it hasn't
>=
>got a locked diaphragm. No problem with the seller refunding, but I'd =
>like to fix it if I could (closet engineer!). Both the depth of field =
>button and the diaphragm actuator arm are locked. The aperture ring =
>turns freely. Any thoughts on how to fix this? What happens if I pull =
>out the three screws holding the lens mounting ring ... a nightmare? Any
>=
>idea of where I could see a blueprint of the lens to help me?
>-------------------------------------
>
>I think I'd return it unless you bought it for a song and just have to
>have a peek inside.
>If you insist, however, I'll quote you from Book 2, page 89 of Tomosy's
>Camera Maintenance & Repair concerning the Zuiko 75-150 f/4.
>
>"...If the diaphragm mechanism needs work, you can access it from the
>rear without taking the front apart (but you can't pull it out). After
>removing the bayonet mount (just three screws), remove the aperture
>indexing tab and the setting and activating levers. All threee of these
>are fastened to the rim of the apreture ring by two screws.
>
>Pull off the rubber grip from the zoom ring and you uncover eight holes
>in the ring. Turn the ring until you see four screws through the
>holes. Remove those four screws, and the rear optical group will come
>sliding out. Mark its exact position first; otherwise, you will have to
>readjust it. Now you can see the diaphragm mechanism and can do some
>minor work on it without pulling it out."
>
>I'll stop there since actually getting the diaphragm mechanism out
>requires removing the front group, cover sleeve, dealing with helical
>threads, the pulley mechanism, removing zoom rollers, you need an
>appropriate spanner wrench, etc, etc. If you don't understand what
>you're doing here you will likely get it apart but never again back
>together such that it works and focuses properly. Best send it to
>somebody or at least buy the book I've mentioned which will teach you
>the general caveats about working with lenses along with the specific
>details of this lens.
>
>Chuck Norcutt
>Woburn, Massachusetts, USA
>
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