Tormach just re-issued the PCNC 1100 Series III upgrade instructions.

I looked at it closely, wondering if it had any "easter eggs", which might reveal future improvements (such as a change of serial # of the machine control board, adding a new connector for an encoder for the spindle, which would allow rigid tapping. Of course, there is that unused 10 pin J7 connector.... that has always been there...)

But I did find one interesting thing. They changed the wiring for the z-axis brake, such that it is wired in series with the machine control board, using the unused J1-7 and J1-8 connectors?

Why? Maybe this would allow the BOB to set the brake on the z-axis when motion isn't commanded? Sort of akin to the normal habit of locking the cross-slide on a mill when turning to get an improved finish?

Previous to this change, the z-axis brake is disengaged whenever the DC board is energized, which it is any time the C1 contactor is shut.

Looking back at the 16 Feb 2016 PCNC1100 manual (an updated from Nov 2014), they updated the wiring diagram in this manual as well. Great, now I am going to have to go on an easter egg hunt in a 224 page manual...