FM2n - help with film advance lever

Discussion in 'Nikon' started by andylynn, Feb 21, 2013.

  1. I have an FM2n that I got on eBay that's in mint condition - except that the film advance lever will advance the film whether or not the shutter has been fired. If I dry-fire the camera with the back open and then work the lever, it will turn the spool, advance the counter and reset the shutter normally. Then I can work the lever again. At the beginning I feel something catch a bit then give easily. For the rest of the action it has a bit less resistance, the spool turns and the counter advances, and at the end of the action the shutter gets nudged a bit.
    Can anybody tell me what's going on here and what to do about it?
     
  2. Andy, given the various issues youve mentioned, it sounds like a cla is in order. Sounds like something is sticking or
    broken.
     
  3. I had an FM which did this. There's something not catching properly in the mechanism under the hood, not much you can do about it unless you know how to dismantle and fix it, which I didn't. I just used it, remembering to wind on immediately after each exposure.
     
  4. Nothing sticking (actually the opposite - slipping), there is nothing really "broken", and it's a relatively simple repair. Quite a common fault that I have seen on numerous samples of the FE/FM series. A full CLA is not required. For that matter, you can continue to use the camera as is and no further harm will result.
    Under the bottom plate near the motordrive coupling is a small spring activated L-shaped hook that prevents a double wind (film advance without shutter release). It hooks over a cam lock attached to the wind shaft after the wind lever is returned to the standoff position following film advance. What has happened to your FM2n is that someone has forced the film advance and slightly bent the L-shaped lever. Even the slightest bend beyond a sharp 90 degree corner will open up the "L" and cause it to slip off the cam lock. That is the "catch" you are feeling when you advance the film without firing the shutter. The L hook is catching on the cam lock but slipping off.
    The L-hook can be replaced, or it can be straightened to a sharp 90 degree L and re-used. Or as I noted above, you can leave it alone. You just have an interlock that isn't working properly.
    The "nudge" you are seeing in the shutter is normal in this situation. The shutter charge lever is just coming to the end of its stroke on the already cocked shutter. So you see no movement in the blades until the lever pulls on them slightly at the very end of the stroke.
     
  5. The "double wind lever lock" is #175 in the attached diagram...
    -
    00bNTd-521279584.jpg
     
  6. Thanks, Michael. That makes perfect sense and looks like something I could probably do myself. Do you know whether the #175 part is the same in other models? I have some broken/parts FAs, FGs, EMs and maybe an FM or two sitting around but no FM2s.
     
  7. Andy - the FM/FE/FM2/FE2/FA all use the exact same mechanism to prevent a double wind. The #175 part *may* be interchangeable among those bodies. I suspect it is, but can't be 100% sure without comparing two of them side-by-side.
    I have always be able to straighten the bent lever. It is a very stiff piece, so needs to be reformed slowly and carefully to get a "sharp L". When you get to the part, it may appear to be barely bent open beyond 90 degrees, but that's all it takes for it to slip off the cam lock.
    The lever is easily accessible with the bottom plate removed. #176 is the spring that activates the lever. Screws are cross-point JIS fasteners, *not* Philips head. The attached photo is an FE2, and shows the lever *before* film advance / shutter cocking. The FM2n has a nearly identical arrangement under the bottom plate.
    00bNUL-521283584.jpg
     
  8. Had a quick look through my files. FE/FM lever is different (same principle however). FM2(n), FE2 and FA lever appears to be identical.
     
  9. I had a simliar problem with an FM2 which was of my own making when I changed the top cover for a new one that I had purchased from Nikon. Under the top cover there is a spring that keeps tension on the multiple exposure lever & I hadn't re-connected it quite right. The clue was that the multiple exposure lever was very floppy & sometimes when I moved the film advance it would move with it & stop the film from advancing. Maybe check your lever to see if it is under tension? If not then the problem may be with the spring under the top cover?
    Good luck with getting it fixed. The FM2 is a lovely camera.
     
  10. Michael R. Freeman, that is wonderfully complete information. Thank you.
    I also have a near-mint FM2n with the same issue. I like to use the FM2n with the motor drive, which neatly avoids the problem. But I worried that I was doing damage to the camera by continuing to use it. I am glad to hear that it is not fatal, nor does it cause any further problems if I continue to use the camera without fixing the issue.
     
  11. Thanks, Michael. That's really, really helpful. I'll open it up and have a look, and open up my dead FA at the same time to compare. I happen to have a JIS screwdriver set coming to me in the mail next week so I'll wait. Aside from this oddity it's probably the best condition manual focus Nikon I've had.
    David, I'll have a closer look at the multiple exposure lever as well. I did test it and it seemed to be working.
     
  12. One more photo from my files for completeness. Bent lever on the left, straightened lever after repair on the right...
    00bNX2-521307684.jpg
     
  13. I just bought an FE2 with exactly the same problem. I think I will just leave well enough alone and get in the habit of remembering to wind it on after each shot so it's ready to shoot next time I use it. Thank you for posting the explanation of the issue. The Internet is great for these things.
     
  14. Update: I fixed it today. It was actually pretty easy, thanks to Michael's help. It was exactly like in the photo above - bent just slightly out of right angle. A needlenose pliers and a hard surface to press against (and it requires less pressure than you'd think) and done. Having the correct JIS screwdrivers also made a big difference, and the whittled end of a bamboo bbq skewer worked well for holding the spring aside.
    I'm just glad it wasn't one of those things where you loosen a screw and it was holding down something with a spring pressing on the back and a dozen parts come flying out.
     
  15. What about this problem I have on my Nikon FM2n, when I advance the film lever then the camera automatically release the shooter, that happened on all speeds. Help needed ???!!! :)
     
  16. I have a similar problem with a Nikon FE. The lever will not advance the film easily. It feels like it is locked and just won't budge. I have not put undue pressure on it. After taking off the bottom, I tried the fix outlined above but it didn't work. I looked carefully at the mechanism while trying to wind it and found what I think is the problem. There is a very small part under the large slotted silver disc in the above picture (part 129?). It is the one held in position by a very small spring and it appears to not be in the correct position. I tried to move it with the tip of a screwdriver when it had a small amount of pressure on it and when I was able to move it the winder worked. Can anyone please tell me how to fix this (Michael perhaps)?
    Thanks in advance (no pun intended).
     
  17. Don't worry guys. Solved with a tiny drop of silicone.
     

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