Nikon FM2 problems

[CristobalCT_ph]

Hi everyone,

I have problems with my Nikon FM2. When I shoot, the camera is at bulb time setting in all overture time settings. To close the mirror or finish this problem, I must push the Depth-of-field preview lever button.
I do know what could be the problem that leaves the camera in "bulb".

I really appreciate any help you can provide.

Cristóbal

 

[Sirius Glass]

Welcome to Photrio.

 

[Andreas Thaler]

I'll see if I can find anything about this issue on the web and in my documentation.

 

[Andreas Thaler]

I do know what could be the problem that leaves the camera in "bulb".

What is your guess on this?

 

[BrianShaw]

The first question is always whether the batteries still have enough voltage and whether all contacts are clean, even if no contamination is visible.

I would therefore treat the battery contact in the camera and in the screw-in part with electronics cleaner and insert new batteries.

If any dirt is visible there, please post a photo.

It’s likely a mechanical problem as the FM2 is a mechanical shutter and wind mechanism.

 

[Andreas Thaler]

I found some posts on the web about this problem but no solution. It probably won't be a sticky mirror shock absorber?

I'm not very familiar with mechanical cameras, maybe @Dan Daniel or @reddesert can help?

 

[Andreas Thaler]

It’s likely a mechanical problem as the FM2 is a mechanical shutter and wind mechanism.

Correct I just deleted my corresponding posts.

 

[reddesert]

I am no great expert on these cameras, I've poked at Nikon FE, FM, etc but never disassembled one fully to understand the mechanism. I have a couple of questions, to clarify the problem, (not to provide a definitive answer).

1. The OP says the shutter fires as if on B. On B, the shutter stays open and mirror up until the release button is let up. Do you mean that the shutter and mirror close when the button is let up, or that they hang up even after the button is let up, until the DOF lever is pressed? If so, does this hang-up happen even on the B setting itself?

2. Does the shutter actually stay open when it is hung, or does the shutter close but the mirror stays up?

3. It is helpful to understand the sequence of events in these mechanical cameras. Usually, and I am pretty sure this is true of the Nikon FM/FM2, the shutter button causes the mirror to rise and the aperture lever to stop down. When the mirror rises, it triggers the shutter to fire. The first "curtain" (actually vertically traveling blades for an FM/FE/FM2 etc) opens, the timing mechanism runs, and the second "curtain" closes and triggers the mirror and aperture lever to return.

It is informative that pushing the DOF button causes the cycle to complete. This suggests that there is some friction or hangup that is preventing it, which is overcome by force with the DOF button. However, that would make more sense if the shutter closes, but the mirror doesn't come back down. It's not clear that the DOF mechanism should stop the second curtain from closing.

One place to look for excess friction in the mirror/DOF mechanism is if the aperture stop-down lever is bent from dismounting a lens the wrong way.

It is possible to remove the bottom cover easily, and you can watch the cocking and firing sequence with the cover off, which is unlikely to reveal a problem if it's in the mirror box/DOF but might be useful if you can see what moves when the cycle is completed.

 

[Chuck1]

Not sure if this is related, I have an fm2 that locks up(mirror sticks up, wind won't wind) after not being used, it is freed up by switching to bulb, then it will work that day, but the next morning it will lock up again.
Wondering if this seems more like a bottom plate,mirror box or aperture lever issue.
I mentioned this in a repair thread hosted by andreas thaler, there someone recommended lifting the shutter with a dental pick and greasing something, just looking for a second opinion...
I have tried smacking it...

 

[Andreas Thaler]

You would have to disassemble an FM to study everything.

 

[BrianShaw]

Not sure if this is related, I have an fm2 that locks up(mirror sticks up, wind won't wind) after not being used, it is freed up by switching to bulb, then it will work that day, but the next morning it will lock up again.
Wondering if this seems more like a bottom plate,mirror box or aperture lever issue.
I mentioned this in a repair thread hosted by andreas thaler, there someone recommended lifting the shutter with a dental pick and greasing something, just looking for a second opinion...
I have tried smacking it...

Did smacking it help? That could be a significant clue!

When winding, is the film spool advancing but the shutter not cocking fully?

 

[Chuck1]

Smacking it didn't help, everything seems to work smoothly except the initial lockup, which is freed by putting it into B, then I use the multi exposure to not waste a frame. I have to finish the roll that's in there and play with it.
There is also an fm shutter issue thread going on that seems similar...

 

[reddesert]

Since it sticks after not being used, it seems likely that it is a little dirty or suffering from dried up lubricant somewhere. There might also be parts that are mechanically binding. Generally, as an amateur, I think cameras should have as little lubricant applied as possible, and that grease usually belongs only on large mechanical interfaces like focusing helicals. I'd really want to be sure before introducing even a speck of light oil into the mirror box / shutter area.

The reason I mention removing the bottom plate is that you can observe some of the winding and shutter firing mechanism, so you could for example try to figure out what stage of the cycle is sticking and what frees up when you switch it to B. The problem is quite likely somewhere that's hard to access, but taking off the baseplate is easy and unlikely to mess anything up.

 

[Andreas Thaler]

Since it sticks after not being used, it seems likely that it is a little dirty or suffering from dried up lubricant somewhere. There might also be parts that are mechanically binding. Generally, as an amateur, I think cameras should have as little lubricant applied as possible, and that grease usually belongs only on large mechanical interfaces like focusing helicals. I'd really want to be sure before introducing even a speck of light oil into the mirror box / shutter area.

The reason I mention removing the bottom plate is that you can observe some of the winding and shutter firing mechanism, so you could for example try to figure out what stage of the cycle is sticking and what frees up when you switch it to B. The problem is quite likely somewhere that's hard to access, but taking off the baseplate is easy and unlikely to mess anything up.

Thanks from my side for the detailed information

 

[250swb]

Sorry for a similar post I just put in the SLR forum but here is the most useful video showing exactly which part gets stuck. It can be lubed simply by taking off the bottom plate

 

[Andreas Thaler]

Sorry for a similar post I just put in the SLR forum but here is the most useful video showing exactly which part gets stuck. It can be lubed simply by taking off the bottom plate

Great, maybe this can also be applied to other cameras, in principle.

 

[BrianShaw]

Sorry for a similar post I just put in the SLR forum but here is the most useful video showing exactly which part gets stuck. It can be lubed simply by taking off the bottom plate

Excellent video that reveals a common problem. I think the word he was struggling to remember is “spring-loaded pendulum cam”, or something like that.

It took me days of interrogating the repair manual to figure that out!

Although this technique is probably best, this repair can also be done without disassembly by using a syringe with naphtha and a cotton bud to soak up the drops of naphtha and dissolved grease. This often needs to be repeated a couple of times as only a drop of solvent can be used to avoid contamination of the other parts. A tiny drop of synthetic oil can be installed the same way.

 

[250swb]

It took me days of interrogating the repair manual to figure that out!

It took me hours of watching other YouTuber videos before I realised it was nothing to do with the arms and levers everybody else seemed to be poking at. Once you know where the cam is it all becomes clear.

 

[Chuck1]

Thanks for the post