[Fiddler]

The Mirror on a Spotmatic SP, will only allow itself to be moved upward, with Finger or Tool, approx. half way it's full travel to the Focus screen.

When using the Camera Shutter, it functions normally, with no issues. On Bulb , again , full travel up down, no problem.

The Spotmatic 11, I also have, allows full up and down with finger .

The SP feels as if it has something blocking it's full travel which is not there during normal shutter operation.

Thinking maybe I should remove top cover to attempt to find solution ?

Any ideas of what might be causing this ?, OR, is this the way the SPs from the 60s were made.

Thank you all.

Fiddler

[stevebrot]

Explain why you are wanting to move the mirror with your finger and why this should be a matter of concern when the intended shutter/mirror actions functions as expected.

That being said, my Spotmatic behaves the same way, with progressive resistance.

Steve

[Fiddler]

It's just something I came across after fitting new Mirror dampers. Lightly moving the mirror up against the new foam Damper is something I do.

Other Two Spotmatics, SP11 and SP1000 , Plus 3 MEs all allow unimpeded movement.

The SP Spotmatic is the only one that resists.

Just wondering why that would be. Perhaps something heading for failure ? , Don't know, hence my question.

[stevebrot]

Lightly moving the mirror up against the new foam Damper is something I do.

Fair enough.

It doesn't surprise me that the SP behaves differently than the SPII or SP1000. Both of those models debuted in the early 1970s. FWIW, on my SV (contemporary with the SP) the mirror also resists being moved by hand. I suspect that Pentax moved to a different shutter sometime in the late 1960s or early 1970s.


Steve

[Just1MoreDave]

I think all the mirror mechanism is on the side of the mirror box with the rewind crank. I am a big fan of not taking apart working cameras unless the goal is to make them unworking.

[Fiddler]

The Sp was a very recent purchase and came with an exceptional original Case.

Primarily bought it for the case.

The Mirror was occasionally hanging up and it was generally "Grubby", and needed a good clean up.

Thoughts of stripping it out for parts have passed . Underneath the top and bottom covers it looks like new.

A little Panel Beating of the top cover to straighten out a few kinks and then all done.

I'm thinking of maybe Glass Bead blasting the top cover, but haven't decided if the factory applied a coating on the base metal, or just bead blasted it and left it that way..

Always more questions !!

Thanks for the input, truly appreciated .

[LesDMess]

Out of curiosity I tried my SP and I can raise the mirror all the way with no resistance. I can also raise the mirrors on my Spotmatic F and ESII but cannot raise the mirrors on my original Asahi Pentax and K.

[Fiddler]

Out of curiosity I tried my SP and I can raise the mirror all the way with no resistance. I can also raise the mirrors on my Spotmatic F and ESII but cannot raise the mirrors on my original Asahi Pentax and K.

Interesting . I just ran a 36 roll of Kodak through my SP without a hitch, yet it's the only one I have, that won't allow me to manually raise the Mirror to the Focus Screen.
Oh well, one of life's mysteries maybe.

Right now I'm debating what to do about the Battery. I have one Mercury original in use , it's years old and still performing.

Not comfortable sticking a 1.55V in there.

And yes, read all the opinions and adapter info., another subject though.

Appreciate your input on the Mirror .
Thanks.

[stevebrot]

Not comfortable sticking a 1.55V in there.

It makes little difference in practice. If you wish, a competent camera tech can calibrate to 1.55V.


Steve

[Fiddler]

It makes little difference in practice. If you wish, a competent camera tech can calibrate to 1.55V.


Steve

Thanks for the input stevebrot. Last couple of weeks I've bought more Spotmatics on EBAY, real cheap with problems , by design.

The last three were almost Mint cosmetically, with just the classic Mirror stuck to Sticky Foam residue. All of them display a "Working" meter. Using the "Standard" Mercury, years old, but still reads good, I set the Aperture and speed at a standard light source with meter needle centered. The closest, but still a different meter display slightly was the 1.4 Volt 312 Hearing aid Battery (in a neoprene collar).

I need to process the negs. to see what results I'm getting, as right now, pretty much in the Dark.

The most recent Spotmatic, a few problems to many this time, so it may end up a "spares unit".

The Focus screen is really messed up, don't know how , maybe some solvent or the like , no clue. Overall though , it's the filthiest Camera I've ever seen. Dragged through a peet bog filthy .

Any ideas who might sell a replacement Focusing Screen ?

Well, old Man is tired. Bed time.

[stevebrot]

The closest, but still a different meter display slightly was the 1.4 Volt 312 Hearing aid Battery (in a neoprene collar).

The camera has a mildly unbalanced bridge circuit that can be trimmed to be fully linear with 1.55V. Even without doing the adjustment, the circuit should give good match to modern meters except at the low end of the meter sensitivity. I have compared the 1.55V cells in both my Spotmatic and Spotmatic II against the meter in several of my other cameras and found a very close correlation.


Steve