Do the servos whistle after doing the manual, power on and start sequence?
Can you jog the X or Y before calibrating it?
Open the right hand cabinet and see what LEDs are lit on the servo amps and fault logic boards after doing the manual, power on and start (before trying to jog or calibrate it).
Then see what LEDs are on after it has faulted. Post up which are lit / not lit (they are named on the board next to the LEDs.
Check the motor brushes in the Z axis motor (four of them, equally spaced around the top half of the motor).
Take off the front cover on the head and see if you can turn the motor by hand in either direction with the servos on (wind it clear of the limit switches before hand) If there is no power there you may have an opto-isolator or two playing up.