Stiff/Stuck Nikon F prism release button, any tips?

[B-9]

I picked up an NKJ F this afternoon, I had been eyeballing on craigslist when after 2 months the owner contacted me and told me to come get it (I had already made a conservative offer when first listed)

To my surprise, it's an early example 6417*** complete with the original square eyepiece eye level prism. The prism has what looks like either debri (foam seal smudge) or more likely de-silvering.

The trouble is, the prism/screen release button is really stiff/stuck. I've tried using a coin (as I already broke 2 fingernails trying) but am hesitant to apply any manly force.

I've owned many F's and this is by far the earliest I've ever seen in person, and would rather not break it. I've also never had one with a stuck release, I've had some that are very stiff (usually caused by the finder) but they would always release after a good wiggle. This one feels solid, but I cannot find any evidence of water damage or rust/corrosion.

Does anyone have any suggestions?

 

[rybolt]

I've seen many of them that were really, really stuck. What I do is take a small screwdriver blade and lay the flat end on the release button. Then I press down hard on the shaft of the blade until it releases. Don't push straight onto the button, of course.

 

[x-ray]

I use the plastic tip of a ball point pen with the cartridge retracted. Metal will scar it but plastic won't.

 

[Dwig]

Sometimes you can relieve some of the load on the finder latch mechanism by pressing down very firmly on the top of the prism. Doing this while attempting to press the release button may help.

Back in the day, when I ran camera stores, I would occasionally encounter this problem when attempting to change the focusing screen for a customer. I usually used some reasonably hard plastic tool (e.g. dense plastic cap for a pen, trimmed handle of an old toothbrush, ...) to avoid scratching the release button.

 

[BillBingham2]

I've used an old plastic film can with the top squeezed to a point.

Bamboo chop stick is my favorite tool of this sort these days.

Try pushing down on the top of the finder when you push in. Not sure if it will help but from what I remember of the mechanism I think it will help take off some pressure.

B2

 

[B-9]

The prism doesn't seem to have any pressure, I've also found this to help, especially with the F2 and it's rubber baffled prisms.

I'll give a pen top a try! Duh 😉 Thanks guys!

 

[De_Corday]

Wait, its not supposed to destroy your fingernails??

 

[Highway 61]

The prism doesn't seem to have any pressure, I've also found this to help, especially with the F2 and it's rubber baffled prisms.

This normally works with all F and F2 prisms. If the prism doesn't budge when you press on it, it may be that the foam under the prism seat over the rear panel of the camera has fully deteriorated and as a result the release mech is now full of sticky goo - hence the release button having no effect.

In this case I'd try to heat the camera with an hairdryer all around the prism seat. Not too much, but enough though.

The prism release button is somewhat hard to depress, yes, but all of mine got released by my fingernails eventually.

Seems that you're also in for a prism dismantle if you see black goo in the VF. For this you need to get access to four screws which are under the prism top cover leatherette, which may get torn into several pieces when you try to remove it. Again - gently heating it may be of some help.

 

[Frontman]

The lever also unlatches the front pins on the prism via a plate which shifts to the side. Sometimes this plate does not shift, so the rear of the prism seems to come up a little, but the front stays put. I have had luck loosening the front catch by removing the Nikon name plate, and adding lube through the gap with a syringe. If you have another F laying around, you can see where this latch is when the prism is removed. If lubing doesn't free it up, you will need to make a tool to reach in and push the latch off the catch pins.