DIY shutter release adjustment
Want to DIY adjust the movement and smoothness of your M's shutter release? Then have a look at the following detailed instructions in the LUG archive:
In Feb 2002 however, the author of the above article - John Collier - posted these additional caveats:
Unfortunately it is not all peaches and cream. If you move the flat spring over too far, which can even mean moving it all, it affects whether the second curtain is held after the first curtain is released. The arrester "B" does not engage as it is controlled by the same flat spring. What happens is that all your high speeds are 1/1000, 1/30 to 1 sec are normal and B is 1/1000 too. One person adjusted his release point and had the above symptoms and emailed me. I fiddled with my camera and immediately had the same problem. So you might be able to adjust your release point or you might not. Go slowly and put it back where it was if all goes awry.
DIY s/speed adjustment
See this Oct 2002 discussion at <Photo.net: #003vw5>.
Tweaking M6 top shutter speeds
Wondering about the small black plastic sphere on the M6/M6TTL top plate at 6-o'clock to the s/sped dial? It is actually a removable plug which covers an access hole to allow technicians to fine-adjust the 1/500th and 1/1000th shutter speeds without having to remove the camera's top plate.