Spotmatic F - Sticking mirror

[SMBooth]

I have a Pentax Spotmatic F which is in really nice condition except for the meter not working, no big deal and the mirror not returning Mostly when you shoot at 1/8 or slower shutter speeds, but sometimes at faster speeds. Any idea want could be wrong?

Cheer
Shane

[Ian Grant]

Could be the damping foam has gone sticky with age. Look inside with the lens off at the front of the focus screen I think there's a piece of foam there from memory, my camera's back in the UK so I can't go check

Ian

[SMBooth]

Thanks Ian, I meant to say that if I give it a little help it wants to stay up, if it was sticking to foam I assume once the seal broke it would come down.

[ntenny]

I had a problem like this with an SP500. I ended up having to take off the bottom plate (at the suggestion of someone here) and fiddle with one of the shafts in the shutter linkage to get it to come back down. In my case the root of the issue seemed to be with a little L-shaped pawl that needed to be minutely bent with needlenose pliers to change where it engaged. It's worked fine ever since (although I can't get a decent shot with this body---the meter is something like six stops off and I think the focus is a bit out of adjustment, but at least that's a *different* problem).

-NT

[jfdupuis]

I had a Spotmatic ES that has this problem once. The problem was quickly solved by lubricating the shutter mechanism after removing the bottom plate. Only one drop of oil from a needle was enough.

[Trask]

You don't say if it only sticks when you've used the in-camera meter. I had a Spotmatic in which the mirror wouldn't quite go all the way up because, when you push down the switch to activate the meter, it's the up-swinging mirror that hits a lever in the mirror box to release the switch. It occurs to me that maybe in your case the mirror is hitting the same lever, but is actually getting caught in a "friction fit" with the lever. Easily seen just by pulling the lens and watching the mirror movement.

[SMBooth]

Thanks, have solved one problem the meter, it now works. In ever knew I had to use stop down metering on the lens i have. - Operator error, the easy ones to fix...
Might try the oil, when it locks up I have to give a small clog a tiny push and it unlocks, other then that I will send it to repair man.
Trask, there is no meter switch on these camera.

[Trask]

Hmm...if it's Spotmatic F, I believe it does have a meter switch. It should be right where the red circle indicates....

[SMBooth]

Hmm...if it's Spotmatic F, I believe it does have a meter switch. It should be right where the red circle indicates....

As far as I can tell that's for stop down metering, and it operates the pusher at the bottom of the mirror box, which is quite clear of the mirror. The meter is always on. After read your first post I had to find out what that switch did, and that's what led me to getting the meter working. But operating that switch does not cause anything I can see in the mirror box to jam the mirror up. Do appreciate your help.

[Trask]

It's very possible that my Spotmatic is an older model and they changed the internals. In my camera, if you remove the lens, look into the mirror box with the mirror in the normal down position, on the right-hand side of the box up near the focusing screen is a small protrusion. When I push down on the meter switch, this cause the protrusion be stick out. When the exposure is made, the mirror swings up and strikes the protruding device just as it reaches max elevation, and the meter switch is released to return to its original position. As I say, mine is probably an older model.