Olympus-OM
[Top] [All Lists]

[OM] Re: 28mm f/2.8 repair advice

Subject: [OM] Re: 28mm f/2.8 repair advice
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Fri, 01 Dec 2006 08:47:54 -0500
Thanks for the further explanation.  It will be helpful since I'm not 
done nor have I even restarted.  Circumstances have conspired to keep me 
on other things.

Chuck Norcutt

John Hermanson wrote:

> Pin CE1573 goes through slot in CE1561 main tube. This is what prevents 
> lifting of ring. End of CE1573 fits into slot of CE1548.
> 
> On most other OM lenses, a forked tab would protrude through this slot 
> in the main tube, and a simple shoulder screw on the diaphragm ring 
> would engage that tab. Easy lift-out. By now, you are probably done, but 
> I thought I'd explain anyway.
> 
> 
> ___________________________________
> John Hermanson
> Camtech Photo Services, Inc.
> 21 South Lane, Huntington NY 11743
> 631-424-2121 | Olympus OM Service since 1977
> http://www.zuiko.com  |  omtech1 AT verizon.net
> 
> 
> Chuck Norcutt wrote:
> 
>>Thanks, John.  I can see the L shape in the parts diagram but don't 
>>recognize anything that I would have thought would interfere with 
>>pulling the ring straight up.  But I'll certainly follow your 
>>instructions.  I'm intrigued now to see what's actually holding it in 
>>place and, of course, to see what's preventing the full range of motion. 
>>I'm suspicious that the pin was simply misplaced when the lens was last 
>>assembled.  Perhaps it's on the wrong side of whatever mechanism it's 
>>supposed to mate with.  I'll soon see.
>>
>>Thanks,
>>Chuck Norcutt
>>
>>John Hermanson wrote:
>>
>>
>>>The pin on the 28 2.8 is L shaped and connects to the diaphragm control 
>>>cam through a slot in the main tube.  To remove the ring, you'll have to 
>>>take out the 2 screws holding the pin in.  Unscrewing the front lens 
>>>assembly, which would expose the diaphragm mechanism, should reveal what 
>>>the problem is.
>>>
>>>___________________________________
>>>John Hermanson
>>>Camtech Photo Services, Inc.
>>>21 South Lane, Huntington NY 11743
>>>631-424-2121 | Olympus OM Service since 1977
>>>http://www.zuiko.com  |  omtech1 AT verizon.net
>>>
>>>
>>>Chuck Norcutt wrote:
>>>
>>>
>>>
>>>>Hey, here's a real, live, nitty-gritty, on-topic OM post!
>>>>
>>>>I have a 28mm 2.8 which will not open (using the diaphragm ring) to more 
>>>>than f/5.6.  The diaphragm blades open fully when the DOF preview button 
>>>>is not depressed but the diaphragm ring can't be rotated to either f/4 
>>>>or f/2.8.  It hits a hard stop at f/5.6.
>>>>
>>>>I assumed that there must be a problem with the detent ball but was 
>>>>surprised when I removed the filter/detent ring and found that the 
>>>>detent mechanism is fine and there is no appreciable wear on the ring.
>>>>
>>>>I tried rotating the diaphragm ring again without the detent ring and 
>>>>ball installed and it still hits a hard stop at f/5.6.  Then I tried to 
>>>>lift off the diaphragm ring and was surprised to discover that I 
>>>>couldn't.  I can lift the side opposite what I'll call the diaphragm 
>>>>coupling pin (CE157300 on the parts diagram) but that pin acts like it 
>>>>has a hook on the end.  The pin side lifts no more than 1/2mm and stops 
>>>>cold just as though what I think should be a flat bladed pin has a hook 
>>>>on the end and is catching on something.
>>>>
>>>>Any suggestions?  If I remove the lens mount will I be able to see the 
>>>>inside of the barrel and figure out what the obstruction is?  I guess I 
>>>>could also remove the two screws attaching the diaphragm ring to the 
>>>>coupling pin but I hate to disassemble what I don't have to.
>>>>
>>>>Thanks,
>>>>Chuck Norcutt
>>>>
>>>>
>>>>==============================================
>>>>List usage info:     http://www.zuikoholic.com
>>>>List nannies:        olympusadmin@xxxxxxxxxx
>>>>==============================================
>>>>
>>>>
>>>
>>>
>>>
>>>==============================================
>>>List usage info:     http://www.zuikoholic.com
>>>List nannies:        olympusadmin@xxxxxxxxxx
>>>==============================================
>>>
>>>
>>
>>
>>
>>==============================================
>>List usage info:     http://www.zuikoholic.com
>>List nannies:        olympusadmin@xxxxxxxxxx
>>==============================================
>>
>>
> 
> 
> 
> ==============================================
> List usage info:     http://www.zuikoholic.com
> List nannies:        olympusadmin@xxxxxxxxxx
> ==============================================
> 
> 


==============================================
List usage info:     http://www.zuikoholic.com
List nannies:        olympusadmin@xxxxxxxxxx
==============================================

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz