Excessive rubbing between the bowden tube and Y endstop cable caused disconnection one of the endstop terminals.
7:56:10 AM M32 Robot.g
File Robot.g selected for printing
7:54:03 AM G32
Calibrated 4 factors using 4 points, deviation before 0.640 after 0.000
7:50:46 AM Connection established!
I printed the sample object, Robot.g, supplied by RepRapPro.
; generated by Slic3r 1.2.9 on 2015-07-01 at 10:51:31
; external perimeters extrusion width = 0.40mm
; perimeters extrusion width = 0.40mm
; infill extrusion width = 0.40mm
; solid infill extrusion width = 0.40mm
; top infill extrusion width = 0.40mm
G1 X0 Y0 Z4 F4000
G1 Z0.35 F4000
G21 ; set units to millimeters
G90 ; use absolute coordinates
M83 ; use relative distances for extrusion
; retract_layer_change = 1
; retract_length = 3.5
; retract_length_toolchange = 10
; retract_lift = 0.4
; retract_restart_extra = 0
; retract_restart_extra_toolchange = 0
; retract_speed = 50
My Fisher showed filament starvation as it was printing upper part of the robot, which is improper retraction setting.