C8 Maintenance    8. Joint #4 
 
344  C Series Maintenance Manual Rev.2 
8. Joint #4 
 
WARNING 
■ 
Do not connect or disconnect the motor connectors while the power to the robot 
system is turned ON.  Connecting or disconnecting the motor connectors 
with 
the power ON is extremely hazardous and may result 
in serious bodily injury as 
ve abnormally, and also may result in electric  shock 
and/or malfunction of the robot system.
 
To shut off power to the robot system, disconnect the power plug from the power 
source.    Be sure to connect the AC power cable to a power receptacle.
 
DO NOT connect it directly to a factory power source.
 
performing  any replacement procedure,  turn OFF the  Controller  and 
 and then disconnect the power plug from the power source. 
Performing any replacement procedure with the power ON is extremely hazardous 
and may result in
 electric shock and/or malfunction of the robot system. 
 
 
CAUTION 
■ 
Be careful not to apply excessive shock to the motor shaft during replacement.  
The shock may shorten the life of the motors and encoder and/or damage them.
 
Never disassemble the motor and the encoder. 
  Disassembled motor and 
encoder will cause a positional gap and cannot be used again.
 
 
After parts have been replaced (motors, reduction gear units, timing belts, etc.), the 
Manipulator cannot perform positioning properly because a gap exists between the origin 
stored in each motor encoder and its corresponding origin stored in the Controller. 
Therefore, it is necessary to match these origins after replacing the parts. 
The process of aligning the two origins is called “Calibration”. 
Refer to C8  Maintenance 16. Calibration  and perform the calibration after the parts 
replacement. 
 
Joint #4 Electromagnetic brake 
 
Joint #4 Motor 
Joint #4 Reduction gear unit 
 
Joint #4 Timing belt 
 
(Figure: C8-A1401* (C8XL))