Galil: begin not valid with motor off error during homing

Reported from POLARIS during end of cycle homing on 20/12/2024

One axis - W1 - on reaching its home position at ~ +40mm seemed to stop there, rather than backing off a fraction of a mm like all the other axes do (it's "Home" button remained greyed out). I jogged it closed a few mm then hit the Home button again and everything seemed OK.

N3 only reached ~35mm when it hit its home position (I'd have expected it to reach 40mm) - perhaps parts of the encoder are failing so that it's not recording its movement properly (this has happened for a few other axes during the years).

More worrying was what happened during the resetting back to the standard beam size settings. As far as I could tell from the IBEX Device Screens graphics all the axes were moving. But one they had finished, all the horizontal gaps readback numbers remained at ~80mm, suggesting they hadn't moved. I moved E1 and W1 manually to their desired positions and they seemed to move, but left all the others because at this point I noticed there were error messages on the axis control screens in the Device Screens view:

Jaws sets 1 & 2: all 8 axes' screens read Error B Homing Timed
Jaws sets 3 & 4: all 8 axes' screens read Error (I can't remember the exact wording - might have been Motor Stall)