OK, I finally replaced the head in my X axis linear scale that I smushed a few weeks ago. Its a 50800 line per inch reader head. A little overkill...

 The machine has been running good up until tonight. Heres whats going on...

I went to home all axis. Z goes, Y goes, X goes a random distance and just stops and zeros.. huh? Hit home again. Z OK, Y OK, X moves randomly and stops and zero. more huh?

Disconnect scale. X homes normally. Double huh?

Reconnect scale... X only moves randoms distance towards home. If I keep hitting x ref it will eventually get there an hit the home switch and comes off.

Any ideas? I am watching the input leds when it moves and stops and none come on.

ahhh... forget it.

I moved the X home to another port and the problem went away. Must of been some cross talk in the interface board.