I've managed to clean the focusing screen of Nikon FM!!!

[jamietea20]

Like the title suggests, I took the camera completely apart,

1> remove the top cover

2) remove the lens mount

3> remove the light meter circuit

4> clean the screen, viewfinder and the prisms

5> put everything back on.

 

While my focusing screen is now as clean as it can be and dust free, due to the age of the camera, a few things broke on its own. There are:

1) the (+ o -) label , so now it just shows a red dot for each

2) I had to replace the supporting foam on which the viewfinder sits Upon opening the camera they fell completely into crumbs. They are actually the cause of the dust in the viewfinder and the screen.

3) A supporting plastic tab next to the prism, it's part of the light meter circuit. But it has no functionality than holding a wire in place.

4) This is the biggest one: the film counter doesn't work anymore. The spring and the numbered wheels showing S, 0, 1...36, now has lost it's original traction , which makes it over turn the numbers per wind. And when I pop the rear gate hoping it'll reset to S, it bounced way over to the bland area before S, and now when I wind the film advance it the counter stays stuck.

 

However, none of this bothers me per se. I'm posting this just to warn people who may be thinking doing the same, try it at your own risk. Due to the age of the camera, a lot of the things won't bear the slightest adjustment.

 

Now, I have a perfectly clear view finder, and all internal foam seal replaced.

[chulster]

That was quite a costly victory, but congrats!

[jamietea20]

That was quite a costly victory, but congrats!

Yes, but I bought it with a 50mm 1.8 for a total of $100 two years ago. So....

[John Seaman]

Something of a Pyrrhic victory.

[rodeo_joe1]

Can't you simply drop the viewing screen out through the mirror box after the removal of just one screw?

 

I seem to remember that the screen retaining frame has a single screw holding it in place, where the release-clip was fitted on later user-interchangable screen models like the FE-2.

[mike_halliwell]

viewing screen

I kinda guessed the rubber/foam bits had got 'higher' than the drop down/out focusing screen?

[John Seaman]

The FM screens are not user interchangeable, unlike those in the FE etc. But there were different versions of the FM. One version, presumably the earliest, had a screen which could be removed from the mirror box. I did replace one some years ago and can't recall details, however the screen was in a kind of springy metal cradle, released I think by removing a screw. Getting it back was a royal PITA though.

[mike_halliwell]

however the screen was in a kind of springy metal cradle

That's what I remember about the FM2N screens

[rodeo_joe1]

Can't you simply drop the viewing screen out through the mirror box after the removal of just one screw?

Yes, you can. I just checked.

 

I remember taking the screen out now. It was some years ago and I just couldn't remember whether it was on the FM or the FE. The screw-head on my FM bears a slight witness mark to having been removed.

The screw releases an L-shaped clip that retains the metal frame and sprung-surround holding the screen in place.

 

It's best to carry out the screen removal procedure with the camera upside down. That way you don't get anything falling on the mirror, which you should protect with a lens tissue anyway.

 

Shame the OP didn't ask advice before wading in and taking half of his camera apart!

The FM screens are not user interchangeable...

Well they are... sort of. You just have to file the handling tab off a later screen. Not sure what effect it has on the metering though.

Edited August 21, 2020 by rodeo_joe|1

[jamietea20]

Can't you simply drop the viewing screen out through the mirror box after the removal of just one screw?

 

I seem to remember that the screen retaining frame has a single screw holding it in place, where the release-clip was fitted on later user-interchangable screen models like the FE-2.

NO, not for FMs... there's no screw.. the focusing screen is sitting in a metal crate. Opening up the camera is the ONLY way to gain access to it.

[jamietea20]

Errr, just have a look at the picture of my FM that I posted.

i don't know what we are arguing here. I own an FM, and it took it apart yesterday, completely... perhaps yours is one of the later models. But mine has focusing screen sits in a enclosed metal crate

[rodeo_joe1]

NO, not for FMs... there's no screw.. the focusing screen is sitting in a metal crate. Opening up the camera is the ONLY way to gain access to it.

Errr, just have a look at the picture of my FM that I posted.

[John Seaman]

As I said, not all FM's are the same, there were variations between different generations. Some have the screw pointed out by rodeo_joe - I think these were the early ones. Some don't have the screw and no doubt require the top off the camera to access the screen as described.

[rodeo_joe1]

Some have the screw pointed out by rodeo_joe - I think these were the early ones

Mine's a late version. Serial number starts with 3 and it has no knurled shutter lock, just a smooth surround to the shutter button. So I think it must be the early ones that need dismantling to get at the screen.

 

There's a

that shows how to take the lid off an early FM. It doesn't look too complicated, but I certainly don't recommend using cyanoacrylate (super) glue next to a prism and screen! The stuff outgasses a white deposit that can ruin plastic surfaces. Better to be patient and use epoxy for any repair.

[John Seaman]

Mine's a late version. Serial number starts with 3 and it has no knurled shutter lock, just a smooth surround to the shutter button. So I think it must be the early ones that need dismantling to get at the screen.

 

Oh right. My present FM, serial number 3068249 (not the one where I changed the screen) also has the screen retaining screw and smooth fixed shutter surround. I think there was another change too - to the safety catch on the back door release, but I can't remember exactly.