Pentax MX problems

[kivis]

Just picked up another Pentax MX at a yard sale with a SMC M 50/1.7 lens. Cosmetically both are like new condition. Lens performs beautifully and is in excellent shape. The body on the other hand has problems. Meter does not work at all, but the worst problem is that it will not focus. It just always stays fuzzy even when the the split image is lined up. It almost appears to be a diopter problem. Any ideas? Is this fixable?

 

[Sirius Glass]

It sounds like the camera needs a CLA to remove the gummed up lubricants and to adjust the works.

 

[Chrismat]

Email Eric Hendrickson at http://www.pentaxs.com/. If anyone can fix it, he can.

 

[David Lyga]

Something is very strange here. Take the lens off. Open the back. Point the camera to a bright light. Look carefully through the viewfinder with your eye at a distance of about one foot away from the VF. Does the VF look odd or different? Then, look at the Fresnel screen from the front. Through the open mount, it is the screen that the mirror almost slaps when an exposure is made. Is anything loose?

I have a feeling that there is no 'diopter' problem but, rather. there is something fundamentally wrong with the mirror/Fresnel/prism alignment. Now the real test:

Ultimately Severe Question: Does the mirror rest upon a piece of metal directly underneath its front section? The mirror MUST be held by that prong, thus precisely angled at a PROPER angle for correct 'apparent' focus to manifest in the VF (thus, congruent with 'real' focus on the film plane). - David Lyga

 

[John Koehrer]

Focusing screen upside down? It shouldn't be possible but never underestimate the abilities of some folks.

While you're looking at the mirror see that it's actually held in place by the clips on it's frame.

 

[David Lyga]

Yes, as John stated, that mirror, ITSELF, must be firmly seated upon its platform. - David Lyga

 

[dynachrome]

Eric Hendrickson has overhauled two MX cameras for me. When an MX is working properly it is a very pleasant camera to use. Changing the focusing screen, as I have mentioned elsewhere, is not the easiest thing to do. I prefer changing screens on cameras which have the focusing screen and condenser in a metal frame. These would include cameras like the Canon F-1/F-1n/F-1N, Nikon F2 etc. Changing screens on a Pentax MX or Canon AE-1 Program or even on a Nikon N90S or FE2 will never be as easy. I recently read somewhere that screens from the Olympus OM cameras may be interchangeable with those from the Pentax MX but I have not been brave enough to try it. If you send your MX to Eric Hendrickson you will get back a camera which works properly and which you can use with confidence. I agree with David that proper placement and alignment of the mirror and screen/screen frame are both important. A Pentax KM does not have user interchangeable focusing screens so the screen stays in place properly by itself.

 

[johnha]

Focusing screen upside down? It shouldn't be possible but never underestimate the abilities of some folks.

While you're looking at the mirror see that it's actually held in place by the clips on it's frame.

The focusing screen on the MX has an offset tab used as a 'handle' for the tweezers supplied with replacement screens. I doubt you can put an MX screen in upside down as the tab wouldn't fit in the frame if upside down. It may be that the frame hasn't been seated properly or has popped down - dropping the frame/screen and re-seating it might help.

John.