Legacy K-mount lenses

Started Sep 17, 2006 | Discussions thread
marvintm Junior Member • Posts: 35
Re: How to fix bad Tamron KA mount

My KA mount is FIXED !! HOORAY !!. Yes it does meter and functions like John Bean says (of course). Thanks for correcting me John. (I still think the new lenses have transistor switched pins inside, hence the funny readings with a standard Ohm meter.)

Now let me repay a few folks with the Good Information....

These KA mounts that seem to malfunction and not register F-stops, are not really overrotating when they are mounted as others have claimed, and some have even redrilled the mount to alter the index pin location. After hours of tinkering and taping off connections, here is the fix. It takes about 5 seconds to perform.

Note the three screw tips on the KA mount that penetrate through (but flush) from the inside of the mount.

These screws are set using locktite. The tip of each screw is inadvertently coated with this stuff and shows a light blue/green color. This happens to electrically insulate the screw tip. In this next photo, the tiny screw head closest to the pins actually sits right on top of the bottom most contact of the camera body. This pin apparently needs to be shorted as well. The fix is obvious, grab your pocket knife, and give a little scrape! You will see a few chips come off the screw tip and viola... better than new. Mine works perfectly now. It's the little things that get ya...

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