Originally Posted by stormbytes
The camera that replaces the M6-TTL (for me, that is) has the adjustment accessible. AFAIK, the TTL model requires you destroy (or remove) a sticker, then adjust using a special (and by special I mean 'expensive') tool.
The M6-TTL was not highly recommended by the Leica tech, unless you shoot a lot of flash, and even then, at 1/50th ? Not very practical.
FYI the sticker that gets destroyed is the "Leica" red dot (both your now returned M6 TTL and your new to you M6 classic have it). The Leica red dot covers a hole used for accessing the adjustment screw and has to come off when making adjustments. As mentioned earlier in this thread, the tool used to make the adjustment is the same for all cameras from M4-P and later.