C4 Maintenance  6. Joint #2 
 
74  C Series Maintenance Manual Rev.2 
6.1    Joint #2 - Replacing the Motor 
Maintenance 
Parts 
AC servo motor 400 W  1 
For the part code, refer to the 17. C4 
Tools 
Hexagonal 
wrench 
width across flats: 2.5 mm 
For M5 hexagon socket set screw 
For M4 hexagon socket head cap bolt 
For M5 hexagon socket head cap bolt 
 
The brake is mounted on the Joint #2 to prevent the arm from lowering due to its own weight while the Controller 
power is OFF or the motor is OFF status.    However, the brake does not work during replacement. 
To replace the Joint #2 motor, tilt the Arm #2 and press it toward the Arm #1. (See the step (3) 
When pressing the arm, put a cloth or a similar material between the arms to avoid each arm from contacting.   
This also protects the arm surfaces and coatings.