OM-2n with sticky shutter and meter problems

Discussion in 'Olympus' started by ondrejp_spyderman, Jan 9, 2008.

  1. Recently I have bought a beautiful looking OM-2n.

    Unfortunately when it arrived it had two major issues. I managed to solve the
    first, but not yet the second...


    1) the shutter speeds on maual were erratic - sometimes fine, sometimes way too
    long (like 2s actual exposure at 1/30s setting). After firing a few hundred
    shots itseems they were getting better.
    I cleaned the variable resistors for exposure meter (above bayonet, in front of
    focussing screen).
    But the variable resistor for manual shutter speeds which is on the bottom side
    of the main circuit board under the bottom of mirror box. It's difficult to
    access without disassembly of mirror box, so I removed the bottom cover and
    tripod mount, and through the opening poured a few drops of lighter fluid on
    the manual shutter speeds variable resistor. Then I worked the shutter speed
    ring from 1/1000 to 1s many times to clean the contacts. It seems this had
    helped as the speed on manual seem to be all fine again.
    I suspect the oil (that is said to contamine the shutter magnet) or some other
    dirt got to the resistor. It seems this one is solved.


    2) the exposure meter in viewfinder reads 2 stops underexposure compared to my
    OM-4Ti with the same lens (which I know is good). The error is almost linear
    (1,66EV in low light to 2,33EV in bright light - can be rounded to 2 stops). Do
    you have an idea what could make meter read 2 stops under ?
    A defective resistor ? Or the strings connecting aperture and the meter needle
    (if someone tried attempted a repair and assembled it incorrectly) ?
     
  2. I have to ask if you have film in the 2N?
     
  3. George: No I don't, but we're talking here about MANUAL mode.

    BTW: I wrote the description and solution of the first problem for reference only - in case anyone else has similar problems.

    I'd like to know if someone else encountered a similar error of exposure meter and how they solved it...

    Thanks in advance.
     
  4. I had the exact same problem with my 2N's manual meter. Unfortunately the only help I can give is that I think it can be fixed without requiring replacement parts.

    I have no knowledge of how to go about adjusting it yourself, I had John Hermanson (www.zuiko.com) CLA my camera and he fixed it for me as part of the CLA. I asked him at the time if the CdS cells needed to be replaced, he said they were fine.

    One thing to check, you don't have any bright lights on behind the viewfinder do you? The CdS cells are beside the viewfinder and can be affected by light from behind.
     
  5. are you sure it's not just the mirror sticking on the foam? i had something like this happen on one of my OM2's. Just open the back of the camera and watch the shutter curtain rather than watching the mirror.
     
  6. Ondrjed,
    You can find the manual for the OM2n here: http://olympus.dementia.org/Hardware/

    I remember there is a section in troubleshooting chapter dealing with this sort of deviations.


    Best regards

    Carlos Flores
     
  7. Thanks for responses so far.

    I'd also like John to take care of it. And if I were in the US I'd send it to him, but I'm from Slovakia, and sending it to John would be way too expensive (shipping, customs duty...). And I'm affraid to let a local repairman work on it.

    No it's not just mirror sticking to foam. I've repalced the foam - for this I even ordered a foam set from John Goodman (interslice on eBay).
    And I can hear the shutter curtains - at 1/30 and slower speeds: first:thwap second:thwap.

    I have all the manuals you mention Carlos. But it's 5 pdf files each about 50+ pages... and the repairs are too complicated and require tools I don't posess like luminance box, some dummy lens etc.
    I also have the SPT articles about OM-20(G) and OM-2S and I think if I had an SPT about OM-2 it would be much easier.

    ******************************************************************

    PS: Please, if you have the SPT article about OM-2 let me know at spyderman at zoznam dot sk. I'd be most grateful.

    *******************************************************************
     
  8. I was thinking about recalibrating the meter by moving the strings that interconnect the meter needle and the aperture ring. If I move the string on the ring, I could fool the meter into thinking the aperture is open 2 stops more and thus the reading would match the other camera. IMO it's quite possible that someone had attempted a repair before and wound the string incorrectly on the (d) meter.
    00NxZP-40884084.jpg
     
  9. You are REALLY asking for trouble if you try to reposition the strings. First, they are "crazy glued" into the aperture ring, and that is going to make the camera impossible to calibrate correctly because the string positions are wrong. Look at it this way: do you really think that all of a sudden (after 20 years of use), the strings are suddenly in the wrong place?

    There must be silver oxide batteries in the camera. Alkaline (A76, LR44) and lithium (CR1/3N) batteries cause big meter needle errors to begin with.
    There is a lever on the back of the meter housing, part ZC1155, loosen large screw, then turn small eccentric screw. This shifts needle position. Depending on where the eccentric already is (could be up all the way or down) you might not have enough to adjust it the way you want. Also, meter should be adjusted to a calibrated light source, at 4 different light levels, not another camera that has not been calibrated. Just sayin'.....this should get you close. Just DON'T recement the strings. John, www.zuiko.com
     
  10. A side note: Meter string diagram you show is incorrect. In the camera, where the string winds onto the spool under the meter housing, diagram shoul show string winding onto the meter from the other side. String actually winds ccw (from this perspective), then spool turns cw as f stop goes from large (1.4) to small (16). John, www.zuiko.com
     
  11. Thank you John. I cannot express how grateful I am. I owe you a lot.

    I did what you said, and it helped. I had to bend the arm slightly, but it worked and now the meter is good again.

    I plan to use the OM-1n and OM-2n only for negs, so a slight error up to 1/2 stop is fine. I've still got the OM-4Ti with its perfect multi-spot metering for slides.

    And once again: Thank you John.
     

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