Pentax Spotmatic

colyn

colyn

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I found a Pentax Spotmatic this last weekend which was working fine but suddenly stopped. With the lens attached the shutter will not fire unless I push the stopdown lever but remove the lens and it works fine.. Looking at the aperture actuating arm on the body does not reveal any problem. It looks to be working fine.

Anybody have any ideas??
 
What lens are you using? Does it do this all of the time, or only when focused to infinity? Some non-Pentax (Yashinon DX lenses, for example) lenses interfere with the mirror on the Spotmatic when focused to infinity. But it may be that your mirror has become loose and slipped down in its track slightly.
 
Your description suggests the problem is with the lens. Does the stopdown pin on the lens move in and out freely? The pin sticks out of the base of the lens and is operated by the actuating arm inside the camera body. When you fire the shutter, the first thing that happens is that the actuating arm flies forward tapping this pin and closing the lens down to its operating aperture. Then the shutter normally fires. If the pin does not move because the aperture is sticky this could conceivably prevent the shutter from completing its firing cycle.

To check, remove the lens from the camera and press the pin on the base of the lens with your finger. Is it moving freely? It sounds to me to possibly be a problem with this pin. If the stopdown lever is actuated it this could alleviate the issue occuring just as you have described. (I was an avid Spotmatic user but have gone digital and its a while so I cant recall all of the details right now).

Takumar lenses can get gummed up causing the aperture to operate slowly or not at all. I have not heard of or experienced myself, the specific problem you are describing, but it could be related to this as a sticky aperture is quite common with old Takumar lenses.
 
I think the first thing I would probably do is to try another screwmount lens on the body (ideally, another auto aperture one) and see if the problem still occurs. This will at least isolate it to the lens or camera body and you can go from there. I've had little to do with the insides of Spotmatics, so can't offer much more specific advice than that, sorry. They're not a bad design though from what I have read. The most common issue is usually the meter.
Cheers
Brett
 
I've had one for 45 years, the meter went out once about 10 years ago. But I was able to use it, but with no meter (so I don't think a meter failure would cause this). In other words everything worked except the needle match. I had Erick fix it and it is still fine. I read that there are something like 5-10 million lenses that fit the Spotmatic. Some of them have to be non- Pentax lenses, and may not function well.
 
It does this no matter which Pentax branded len is mounted and the lens aperture pin on the lens works as it should. So I have ruled out the lens. No matter at what distance I focus to it still does it.
 
I read somewhere in my research on Spotties that they were designed to work only with the SMC Takumar lenses. But then you could have a bad/loose linkage somewhere, especially if it has been worked on in recent time.

PF
 
farlymac said:
I read somewhere in my research on Spotties that they were designed to work only with the SMC Takumar lenses. But then you could have a bad/loose linkage somewhere, especially if it has been worked on in recent time.

PF
Click to expand...
That is just for the Spotmatic ES an ESII, I think, and only if you want to use them as aperture preferred auto-exposure cameras. Otherwise, most any M42 lens will do. My old Auto Takumar lens works fine (and looks gorgeous!) on my SPII, as does my Vivitar screw mount. The Yashinon DX lenses will work, but the mirror hangs up at infinity. The Yashinon DS and DS-M lenses are OK. I had an auto-Sears 28mm that was fine on it too.
 
Try it this way...mount any lens, open the back, set the shutter speed to bulb then trip the shutter...see if there's anything that does not appear normal..
Just thought of this too...screw the lens out one full turn and see if it works...
I just checked on a Vivitar 400SL that if I prevent the aperture arm from moving forward it will still allow the shutter to trip but if I do the same thing on my Spotmatic it won't let the shutter fire...so something may be preventing the lever from moving forward...
 
I've ruled out the lens so I suspect it is body related. I bought this camera a last weekend at a yard sale for $6 so it most likely needs service so I may break it down this weekend and do a good cleaning and service..
 
Easy fix..

It was a broken actuating spring on the mirror box. Dug out an old parts Pentax removed the spring and replaced the broken spring which left a couple of holes in my finger before I was able to get it set in place.
 
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