Nikon F3 Meter staying at 2000+

[nicholasnicholas]

Picked up an F3, sold by a guy that was somewhat unaware or maybe knew of the poor condition of the F3.
Had some corrosion and generally a bit mucky.
Anyways have cleaned it up, new batteries and the shutter fires. A few things i'm chasing some help on:

Shutter sticks at some slower speeds and bulb, maybe it just needs to be worked a lot to wake up again?

Light meter ONLY shows 2000 and the over + on AUTO and doesn't change no matter what light changes.
In manual it shows the shutter speed, but again only a + and never +- or -

Under the mirror, when the shutter is opened there's a circular little lens / window. It looks pretty dirty. Could this cause the meter to always show over and not work?

Any help would be great before I chase up a return to sender on this one.
(It was sold via Ebay as "used" which apparently covers the buyer as the camera should be working, but condition can vary. I should be able to return...)

Thanks all!

 

[M-88]

That little cell under the mirror is the meter cell, as shown here:

Nikon F3 - Exposure Control

It most definitely must be clean to work properly. What puzzles me is that 2000+ is actually an UNDERexposure and dirty cell should probably OVERexpose instead.

 

[nicholasnicholas]

Oh no, here's what it looks like
Is that easy to clean, seems like it might even be from underneath. Fungus WAS present in other parts of the body...

 

[M-88]

If that's underneath the lens, it means the meter cell itself is affected. Alternatively, the meter cell can be intact but a circuit element called FRE (Functional Resistance Element) can be damaged, which renders exposure meter useless. At this point, it might just as well be a guessing game, unless someone else here can provide better insight.

 

[Chan Tran]

I think you should return. Dirty meter cell would result in exactly reverse condition. Also probem with the FRE tends to give you the reverse problem. The meter acts like it sees too much light while both a dirty cell or broken/dirty FRE would result in the meter seeing too little light. I think it could be logarithmic amplifier circuit.
Since you can read the meter reading with the lens cap on. Try it and see if it still indicates too much light?

 

[M-88]

The meter acts like it sees too much light while both a dirty cell or broken/dirty FRE would result in the meter seeing too little light.

This is what I suspected. Thank you for giving more insight.

 

[nicholasnicholas]

I think you should return. Dirty meter cell would result in exactly reverse condition. Also probem with the FRE tends to give you the reverse problem. The meter acts like it sees too much light while both a dirty cell or broken/dirty FRE would result in the meter seeing too little light. I think it could be logarithmic amplifier circuit.
Since you can read the meter reading with the lens cap on. Try it and see if it still indicates too much light?

Hmm, is this a complex fix if it's the circuit? I imagine so.
Are there other things I could try to troubleshoot?

 

[Chan Tran]

I think the meter reading isn't going to change. But you can try to turn the lens aperture and make sure the AI aperture feeler is moving (and of course not moved out of the way). Also turn the ASA dial. But I don't think it would change.

 

[nicholasnicholas]

Gave the above tips a try, no go.
I figured this would be the case, being mostly electronic. Now I'm reminded why I prefer mechanical cameras!

On the off chance, would cleaning and poking around in here do anything?
I wonder if it's simply a bit of corrosion or dirt on an electronic part that's blocking the signals?
I'd prefer to revive a camera than throw it to the heap!

Thanks!

 

[kennethwajda]

Did you get the counter to go to number one? I thought the F3 kept a 1/2000 SS for loading until you get to number one.

 

[M-88]

Did you get the counter to go to number one? I thought the F3 kept a 1/2000 SS for loading until you get to number one.

The problem with OP's camera is not the shutter speed firing at 1/2000 (which it would do until reaching frame 1), but the exposure meter showing the incorrect reading.

On the off chance, would cleaning and poking around in here do anything?
I wonder if it's simply a bit of corrosion or dirt on an electronic part that's blocking the signals?

I think it's extremely unlikely. Of course you can always give it a try. Some sort of knowledge of electric repairs, a service manual and corresponding tools would be a good start in my opinion. That's what I did with Olympus OM cameras.

 

[Chan Tran]

Gave the above tips a try, no go.
I figured this would be the case, being mostly electronic. Now I'm reminded why I prefer mechanical cameras!

On the off chance, would cleaning and poking around in here do anything?
I wonder if it's simply a bit of corrosion or dirt on an electronic part that's blocking the signals?
I'd prefer to revive a camera than throw it to the heap!

Thanks!

You need the service manual. If you can't find one on the net let me know. I know I have the pdf copy somewhere. There is some point in there you can measure the voltages. It can pretty much tell you what's wrong. To fix it it is another thing.

 

[Chan Tran]

Did you get the counter to go to number one? I thought the F3 kept a 1/2000 SS for loading until you get to number one.

Before frame 1 the F3 is set at 1/80. There isn't + or - indication.

 

[Chan Tran]

I would add that if you can check and verify that the camera would function perfectly fine in manual except the meter indication is always +. If this is so the problem is entirely the metering circuit. The signal from the photocell is fed into a logarithmic amplifier to convert linear light brightness into a voltage that is proportional to the EV (EV is log of the light intensity). Then this voltage is fed into a subtraction amplifier that subtract the voltage generate by the FRE (which is the resistor that connect to the aperture coupling and ASA dial). This resulting voltage would then be fed into the meter display and the shutter speed control circuit. If I remember correctly all these votages can be measure with only the bottom plate removed and the manual would tell you the values you should expect to see.
Now that I am saying it. The problem could be entirely with the meter display. Because if the voltage fed to it is correct but it still display wrong then you still have correct automatic shutter speed in A. Try that. have the camer inside where it's relatively dark and fire the shutter in A settings and see if the shutter speed is long?

 

[kennethwajda]

Before frame 1 the F3 is set at 1/80. There isn't + or - indication.

Ah, ok. Thanks.

 

[Christiaan Phleger]

To me it sounds exactly like a cracked FRE, I would check for damage on the rewind side of the camera. For such a durable design and tool, this corner is a surprising subtle weak point.

 

[M-88]

For such a durable design and tool, this corner is a surprising subtle weak point.

Putting a flash shoe on the rewind lever automatically makes it a weak point imo.

 

[KinoGrafx]

Wow I used F3s full time (and hard!) for about 8 years straight and never had one of those problems- or any problems really - with them. That one sounds like a basket case and something that should be returned. Maybe it spent the last couple decades in a dank basement or something?

 

[Chan Tran]

Before frame 1 the F3 is set at 1/80. There isn't + or - indication.

Before frame 1, if the shutter speed dial is set at A then the meter will display 80 and the shutter speed is fixed at 1/80.
If the shutter speed is set at 125 to 2000 then then the display is also 80 and the shutter speed is 80.
If the shutter speed is set between 80 and 8 sec then the display is the same as set speed and the shutter speed is the same as set speed. So in manual you can release the shutter with speed from 8 sec to 1/80 but not faster.
Once in a while I need to review the manual for sure.

 

[nicholasnicholas]

Wow I used F3s full time (and hard!) for about 8 years straight and never had one of those problems- or any problems really - with them. That one sounds like a basket case and something that should be returned. Maybe it spent the last couple decades in a dank basement or something?

Most likely! I have since returned. Thats the 2nd F3 i've owned that has failed, electronically.
Maybe not so robust and tank like after all as the reviews all say!

 

[KinoGrafx]

Don’t give up on the f3 just yet, find the right one and it will be your friend for life

 

[nicholasnicholas]

Don’t give up on the f3 just yet, find the right one and it will be your friend for life

Haven't given up yet!
Got another one that was "working" - film counter won't reset from 40 (little button seems stuck!) and sometimes the meter shows -8- when it's not appropriate to the light. Oh dear

I moved the ISO dial and seems to be helping the - 8- LCD and exposure, but the film counter is still stuck after cleaning the area.

Any advice on these for fixes?

 

[Chan Tran]

See if the little pin on the back of the camera is stuck in. When you move the ISO dial seems to help then it's the FRE is dirty.

 

[nicholasnicholas]

See if the little pin on the back of the camera is stuck in. When you move the ISO dial seems to help then it's the FRE is dirty.

The little pin in the film door is flush, won't budge or pop out. Thinking of ways to loosen it or get leverage on it to pop it out again... Any ideas?
Better news that a dirty FRE could be the thing not cracked!

 

[Christiaan Phleger]

I would give that pin a bit of a nudge with a toothpick or such. If that resets it, then the counter mechanism needs a clean; debris and such can and does fall into that spot.

I agree that multiple rotation cycles of the FRE (exposure compensation as well) could help, but if there is one spot on the settings where it goes haywire then that's likely a sign of a crack. It happens.