Nikon F3 - stuck always on

Required · Jul 28, 2022

I bought a F3 cheap for spare parts as it's in a very good shape.
After fitting it with new batteries it works "almost" perfect.

It appears to be stuck at always on even if I turn the power switch off.
The light meter works perfect and so do the advance lever. The first frames of 1/80 and following ones is correct.
But the shutter release button does not do its job. I have to use the mechanical backup lever to get the shutter and mirror to release.
And when I do the timings are correct.

Before I tear it down for parts - have anyone had this problem before and know what might be wrong with it?
My first thought is that it might be the power switch and release contact springs that's messed up or stuck.

George Mann · Jul 28, 2022

Ken Rockwell leaves his on all the time, with the batteries lasting over 2 years without use, so you would probably be fine leaving it as-is.

Required · Jul 28, 2022

Well usually the light meter times out and turns off after a few seconds.
But not on this body. The meter is always and constantly on no matter the position the power switch have.
I don’t believe the battery will survive 24/7 for two years.

Sirius Glass · Jul 28, 2022

I have the Nikon N75, N80 and F100 and they all have a slow battery drain for the display that cannot be turned off. If I am going to leave the camera empty for a while I pull the batteries and leave them next to the camera on the shelf. When I go to use the camera, I reload the batteries and film.

BradS · Jul 28, 2022

Required said:
Well usually the light meter times out and turns off after a few seconds.
But not on this body. The meter is always and constantly on no matter the position the power switch have.
I don’t believe the battery will survive 24/7 for two years.

wild guess...broken or severely corroded wire(s), leaky capacitor(s), water intrusion & damage

Huss · Jul 28, 2022

The mechanical back up lever only fires at the one mechanical speed.

Chan Tran · Jul 28, 2022

I believe for some reason the shutter is always pressed.

Required · Jul 28, 2022

Huss said:
The mechanical back up lever only fires at the one mechanical speed.

It actual fires according to the set shutter speed.

Huss · Jul 28, 2022

Required said:
It actual fires according to the set shutter speed.

So if you set the camera manually to, say, 1/2 sec (so you know it is a long exposure) using the mechanical release fires it at 1/2 sec?

And what does it fire at when you take the batteries out?

reddesert · Jul 28, 2022

Have you consulted the Nikon F3 repair manual and articles available at https://learncamerarepair.com/ ? The service manual has some useful descriptions of the firing sequence (that is, it is more informative than just a bunch of exploded diagrams). It seems a bit extreme to say that you are on the verge of tearing it down for parts.

I don't have experience with this particular problem, but IME many electrical problems are due to electromechanical issues - bad contacts, dirty switches, etc - much more than actual failed electronic components. I agree with Chan Tran that a possible explanation is that the shutter button switch is stuck closed. Trying to clean and test all the switches that are in line to turn on the meter would be my first line of approach.

250swb · Jul 28, 2022

Take the head off to switch it off?????

Required · Jul 28, 2022

Huss said:
So if you set the camera manually to, say, 1/2 sec (so you know it is a long exposure) using the mechanical release fires it at 1/2 sec?

And what does it fire at when you take the batteries out?

Yes. All set times fires accordingly to set values. 1/1000 or 4s etc.

I’ll begin to strip it down tomorrow with the service manual as my guide.
Hopefully it’s just a simple mechanical/electrical short in the switch.

I’ll report back as I progress.

Chan Tran · Jul 28, 2022

Required said:
It actual fires according to the set shutter speed.

Yes the mechanical level will fires the correct electronic controlled speed if the meter is still on. So if you have battery in the camera and want to use the mechnical speed you have to wait until the meter times out and turns off. Also the power switch only keep the meter from turning on but not turning it off. It's the time out that turn it off. I believe if the OP turn the power switch to off. Remove the battery and reinstall the battery the meter would be off.

barks110 · Nov 21, 2022

Required said:
Yes. All set times fires accordingly to set values. 1/1000 or 4s etc.

I’ll begin to strip it down tomorrow with the service manual as my guide.
Hopefully it’s just a simple mechanical/electrical short in the switch.

I’ll report back as I progress.

I’m very curious what you found/if resolved? I have the same problem with an F3 body.

Huss · Nov 21, 2022

George Mann said:
Ken Rockwell leaves his on all the time, with the batteries lasting over 2 years without use, so you would probably be fine leaving it as-is.

Do u really believe that? He turned the camera on, made a note of the date, then came back two years later and checked his notes to see when he left it on?

Moose22 · Nov 22, 2022

Required said:
Yes. All set times fires accordingly to set values. 1/1000 or 4s etc.

This is wonky.

According to the manual:

The shutter operates at a mechanical speed of approx. 1/60 sec/ at any setting on the shutter speed dial except "T." At "T," the shutter remains open until the dial is turned to another setting.

awty · Nov 22, 2022

barks110 said:
I’m very curious what you found/if resolved? I have the same problem with an F3 body.

You could give the switch a quick blast with electronic contact cleaner. If that doesn't work, then take the top plate of for better access to clean.

Huss · Nov 22, 2022

awty said:
You could give the switch a quick blast with electronic contact cleaner. If that doesn't work, then take the top plate of for better access to clean.

I have fixed so many cameras by doing that! Totally serious. But it has to be that exact cleaner, as it evaporates instantly leaving no residue.

George Mann · Nov 22, 2022

Huss said:
Do u really believe that? He turned the camera on, made a note of the date, then came back two years later and checked his notes to see when he left it on?

Everything needs to be taken with a grain of salt.

gone · Nov 22, 2022

Put a lens cap on it when you're not using it. No light = no meter activity = no battery drain. Not a fix, but it's easy, and will work.

I like Ken Rockwell. He's crazy, and he has the ethics of a realtor/lawyer, but that's OK. Love his articles, which are really thinly disguised ads for all manner of things, mixed w/ begging for money to feed his family (as if!). They're what makes Ken, Ken.

I should send him $2 for cat food, it's the holidays.

MattKing · Nov 22, 2022

momus said:
he has the ethics of a realtor/lawyer

In my experience, that is a true dichotomy!

Huss · Nov 23, 2022

momus said:
Put a lens cap on it when you're not using it. No light = no meter activity = no battery drain. Not a fix, but it's easy, and will work.

That is what is said in the owner manuals for the Leica M5 and Olympus Pen FT to turn off the meter. The difference between the two is the M5's meter is on when the shutter is cocked, while the Pen FT is on all the time.

lxdude · Nov 27, 2022

Huss said:
So if you set the camera manually to, say, 1/2 sec (so you know it is a long exposure) using the mechanical release fires it at 1/2 sec?

And what does it fire at when you take the batteries out?

My F3 fires with the mechanical release at the speed set on the shutter speed dial, if good batteries are in it.
If the batteries are dead or out, 1/60th, according to the manual. (One version of the repair manual says 1/55th). T also works if it is set to it.

Nikon F3 - stuck always on

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