Konica Autoreflex T3 fault

[archive59]

I'm posting this just on the off chance someone here has come across this problem or is familiar with the Konica AR lens mount.
The Hexanon 50mm 1.7 lens is not stopping down when the shutter is released on the Konica Autoreflex T3 I have just acquired. The DoF preview switch does not move to stop down the lens either. When the lens is off the camera the aperture is as set. The lens registers and locks into place with no apparent problems. Am I missing something obvious?

Thanks, Mark

 

[konicaman]

Not to be impolite - but I assume you have batteries in the camera, and that the meter is giving a correct reading? If not, the lens will only stop down on manual settings. I have been using T3's for more than 30 years, and have only seen this once, due to a slightly bend aperture arm on the lens, which could be corrected carefully with a set of pliers.

 

[archive59]

Not to be impolite - but I assume you have batteries in the camera, and that the meter is giving a correct reading? If not, the lens will only stop down on manual settings. I have been using T3's for more than 30 years, and have only seen this once, due to a slightly bend aperture arm on the lens, which could be corrected carefully with a set of pliers.

Yes I have put a fresh set of (all be it with incorrect voltage) batteries in, but the problem is present when setting the aperture manually. Looking as best as I could at the way the mechanical linkage all fits together I had thought there was a possibility of what you have said regarding the arm. It doesn't really look out of shape though. What is confusing me though is that the aperture opens up from its setting as the lens is mounted on the camera which I would have thought indicated that the arm was in contact with what it should be, if that makes sense.
Thanks for your help with this.

 

[konicaman]

Yes it makes perfect sense. The little lever in the lower part of the bayonet is supposed to give a push at the arm, when the shutter is fired (or you push the DOF arm). I have never heard of that function being broken, but anything is of course possible on a 30+ years camera. The mechanical construction was not as strong on the later plastic/electronic versions and these are know to get worn or completely broken (especially when using Tamrons Adaptall 2), but not so with the T3s. Have you other lenses and/or bodies to test with?

 

[archive59]

Yes it makes perfect sense. The little lever in the lower part of the bayonet is supposed to give a push at the arm, when the shutter is fired (or you push the DOF arm). I have never heard of that function being broken, but anything is of course possible on a 30+ years camera. The mechanical construction was not as strong on the later plastic/electronic versions and these are know to get worn or completely broken (especially when using Tamrons Adaptall 2), but not so with the T3s. Have you other lenses and/or bodies to test with?

Unfortunately I do not have either another body or lens. This is my first foray into the world of Konica SLRs and I was hoping to get a feel for how both the bodies and the hexanon lens perform. I just wasn't expecting these sorts of problems so early on.
You are quite right in saying anything is possible with a camera this age and by the amount of brassing on the black body it does seem to have actually been used a fair amount. It is a T3 as opposed to the later T3n and nothing that is visible in the camera mount area is obviously broken or stuck apart from the DoF preview lever not moving when the lens is mounted. I have tried to visualise what is happening and one thing that confuses me is that the ring with the tab that pushes against the aperture tab on the lens when it is mounted does not move at all when the shutter is released. This is from what I can see with the back open and the shutter on B. I think I'm confusing myself so I'm not sure you will understand what I'm saying.
I'm just not the sort of person to discard a camera so I'll probably try and track down another T3 to compare with.

 

[archive59]

I really am wasting too much time on this, but I think I am making some progress. The DoF preview lever now moves and does what I think it should except for actually step down the aperture. It seems that either the spring tension in the lens on the aperture tab is too weak, or the ring in the camera mount that it pushes against is in need of lubrication. If only I had another lens I would be able to narrow this down.

 

[konicaman]

Well just took a look inside my T3 - the whole ring is supposed to move when the shutter is released (or the DoF lever is pushed) about 20 degrees I'd say. At the same time 2 chrome "thingies" are coming out at app. 120 degrees to both sides of the aperture lever - no idea what they are doing; probably just pushing the ring?

The aperture arm on the lens should be rather easy to push and the aperture should of course open and spring back as soon as the arm is released. I would describe the feeling as "spongy" .

I have a spare lens (50/1.7 as far as I recall), in perfect working order except for the filter thread. It is your to have, if you'll pay the postage .
You can see it here:
http://rangefinderforum.com/forums/showthread.php?t=91101