Nikon F3 shutter speed off when 1/125 and slower. Mechanical shutter too.

Discussion in 'Nikon' started by lasselarsen, Sep 2, 2020.

  1. Hi all,

    I have an odd problem with my Nikon F3.

    Preface:
    Batteries are brand new. Battery connectors have been cleaned.

    The problem is the same on “A” as on manual shutter speed setting.
    The problem persists no matter which frame I am on 0-40.

    Problem:
    When I shoot at speeds slower than 1/250 the shutter stays open for much longer.

    Examples:
    1/125 = 1/10 (or as long as you keep the release button pressed)
    1/60 = 1/5
    1 = 30 sec
    4 = 120 sec

    to make matters weirder, the mechanical shutter will also stay open for too long. The mechanical shutter is supposed to be 1/60 no matter what. But it follows the pattern above.
    It does so even when the camera is off. It will still have too slow speeds and the speed will depend on the manual shutter speed setting.

    The only way to get the true mechanical shutter speed is by removing the batteries. Then the speed will stay at 1/60.

    If anyone has any clue to what could cause this, I am very excited to hear ideas.

    Is it simply just fried ?
     
  2. Send it in for a CLA.
    Might simply be dried old grease on the slow speed gears or mechanism.
    I don't know if the F3 uses a mechanical or electronic shutter.
     
  3. +1
    Electronic. IIRC, it's the same shutter mechanism as in the F2, except its electronically controlled and not - as in the F2 - mechanical.
     
  4. The F3 has a delicate FRE (a printed resistor element - no idea what the F stands for - maybe 'fragile') that works to regulate the speeds in conjunction with the meter. It's basically coupled to the AI aperture follower with a bit of string.

    The FRE can easily get cracked, which is pretty much irreparable, or get dirty, which is fixable. Either fault will send the shutter speeds way off. If working the shutter speed dial backwards and forwards a few times makes no difference, then the FRE is probably cracked, rendering the affected speeds unusable.
     
  5. The OP said in both manual and auto the FRE (Furntional Resistor Element) only affect the auto speed.
     
  6. It could be up to 40 years old. Weigh the cost of a replacement against repair—provided it’s available. They’re tough but not immortal.
     
  7. Nope. I have an F3 with a busted FRE and all speeds above 1/125th fire at 125th. Manual, Auto or whatever. Apertures below f/8 don't register either.

    Don't know about 'furntional' or even functional. It stands for F*cked up Resistor Element as far as I'm concerned.
     
  8. I am sure it's not the FRE problem alone. In manual the F3 doesn't get any signal from the FRE except for the display but the speed that it fires at is strictly from the shutter speed dial which is not a resistor but a 5 bit gray code encoder.
     
  9. Thanks so much for the quick responses.
    Had heard the the FRE might be the problem.
    But if the FRE is only affecting Aperture Priority, then it wouldn't be that.
    I would have to look at schematics to full understand what is going on.

    As far as I know, time intervals in a chip is decided by processor clock cycles.
    Do you think the 5 bit encoder could be affected by stuff like lubricants or water? The camera smelled like 'rifle oil' when I bought it. Don't know if wrong lubrication could hinder the transistors.

    The fact that the shutter dial setting affects the speed when the camera is OFF and triggered via mechanical trigger makes me a bit worried.

    Will probably bring it in for a CLA and then in worst case sell it for parts.
     
  10. Actually I found a post about my exact problem.
    Nikon F3 all speeds were slow - quick fix

    Now I just need to figure out how to disassemble the ring around the shutter button.
    Pulling, pushing and/or turning it doesn't seem to do anything.

    If anyone has a good tip on disassembly it would be greatly appreciated. I looked at the official repair manual but can't find heads and tails in it. It refers to several tools i don't know.
    But of course I could just pay a pro to do it as well.
     
  11. You'd probably need a rubber cup to turn that ring.
    Richard Haw is a good source for DIY Nikon repair. As far as I can see, he has no F3 instructions, but the EM shares a similar film-advance/shutter-button design, so maybe you can find inspiration there:
    https://richardhaw.com/2018/09/27/repair-nikon-em/
     
  12. The shutter speed is controlled by a voltage fed to the shutter timing circuit. This voltage is affected by the FRE, the meter, the ASA dial etc.. in auto. In manual the 5 bit encoder generate a voltage to feed this circuit. I think both are OK but with the correct voltage fed to it the shutter control circuit doesn't work correctly.
     
  13. Friction wrenches can usually be fabricated fairy easily. Rubber sheeting and O rings are a good start and can be super-glued to a wooden tommy-bar.

    For example: The LH thread cap of an F2 leverwind needs a friction wrench, and a small piece of rubber matting stuck to a flat wooden lollipop stick did the job for me.
     
  14. One more thing which is worth to try. Set the camera on auto. Press the AE lock button and see if the shutter speed is droping. If so the hold capacitor is defective.
     
  15. Richard Haw's blog is really good.

    I gave the shutter ring another try with just my hands.
    Turns out you just need to pull the wind lever rather strongly clockwise while turning the top ring counter clockwise. Feels a bit wrong, like you might break something. But I got it off.

    I followed Robin Guymers steps though without spraying lubricant. Just fast drying contact cleaner.
    Quick spray down the "shutter button hole".
    Tiny drops on the electronics visible on the underside when removing the bottom metal cover.
    Let it dry.

    For about 100 shots all the shutter speeds were reverted to the exact correct speeds! I was very pleased.
    I then left it to sit over night.
    Next morning the shutter speeds down to 1/60 were correct. But all the slower speeds were again way off by seconds.

    Now I have repeated the process, but with more Contact Cleaner on the electronics under the bottom cover.

    Currently it shoots exactly correct speeds on all settings. But I have to let it sit for a couple of nights to see if anything changes.

    If shutter speeds go off again my next step will be to remove shutter dial and see if I can spray contact cleaner more directly on the electronics through there.
    Otherwise I might have to disassemble it further and get into the specific components that are acting up.

    Will update again when testing later this week.
     
  16. The F3 is one of those cameras that works great and very reliably for a long time, but can be infuriating and impractically expensive to fix when all is not right.

    I bought a cheap one several months ago. I go back and forth on whether or not I like the HP finder, and at the time didn't have one so couldn't resist(figured if nothing else i could stick it on my good body and try again).

    I had basically the exact opposite problem of you-the slow speeds were good, but the high speeds were WAY off to the point that 1/2000 usually didn't open at all, and down to the mechanical speed(and even a bit below) speeds were off by over a stop in some cases. My shutter speed tester has a single "eye" and I got radically different measurements across the frame. I'm sure the error was still there in slower speeds, but with a roughly 1/80 second curtain travel time, the error is really insignificant at say 1/15. Fortunately, I actually was able to fix mine by increasing curtain tension. Per my understanding of the shutter manual, if you get 1/2000 correct and the electronics operate correctly, all the others should fall in line behind it.

    In my case, though, the first time I got it "right' they were off again the next day. I went through it a few days more, and each day the decline in error would change until it finally settled down and held. The last I checked, it was still on, although I really want to send the camera off for a CLA before I trust it. Since I'm not really an F3 guy(I much prefer the F2, and like the polarizing F4 over the F3) I've had higher priorities than having that one fixed properly.
     
    lasselarsen likes this.
  17. Just wanted to follow up on the progress. F3 has been running perfect shutter speeds for a week now. Have run some 100-200 shots on it. Have put film in and it is still going strong.
    For anyone with similar problems, here is the link again to the guide I followed.
    Link: Nikon F3 all speeds were slow - quick fix

    Hopefully it keeps going for years. I really appreciate all the responses and it's great to know that there is still a strong Nikon F community here with real technical expertise.
     
    NHSN likes this.

Share This Page