FANUC Robot Controller Repair Case Study

Check and Repair

Controller Component

Check 1: The controller circuit breaker is on and has not tripped

Repair: Close the circuit breaker

Check 2: Check the LED indicators on the power supply board (PSU) (GREEN) to see if they are lit.

Repair: If the LED indicator is off, it may be that the 200V power supply to the PSU is missing or the F1 fuse on the PSU is blown:

1 If the 200V power supply is missing, please check the power supply line

2 If the 200V power supply is provided to the PSU, please cut off the power:

A If the F1 fuse is blown, refer to Repair 2

B If the F1 fuse is not blown, please replace the PSU

Repair 2: Causes of blown fuses and countermeasures

A Check if the CP2 and CP3 connectors between the PSU and other circuit boards have good contact.

B If surge absorber VS1 is shorted, please replaceVS1 part number: A50L-2001-0122#G431K

C Diode DB1 shorted

D Backup power module H1 damaged

If B or C has a fault, please replace the corresponding spare parts

F1 part number: A60L-0001-0396#8.0A

Check and Repair

Controller Component

Check 3: Check the signal wiring for EXON1, EXON2, EXOFF1, EXOFF2 on the panel board

Repair: If the external power switch function is not used, please short-circuit the signals EXON1 and EXON2, EXOFF1 and EXOFF2; if the external power switch function is used, please check the connecting cable.

Check 4: Check if the connection cable of JRS11 on the main board or panel board has good contact.

Check 5: Check the top 1, 2, 3 to ensure the 200V power supply on CP1 is connected properly and the machine ON/OFF switch is normal. Please follow these steps to check the PSU:

If the LED on the PSU (ALM: red) is lit, please check if the external +24V is grounded or connected to 0V.

A If the F4 fuse is blown

B Replace the PSU

F4 fuse part number:

A60L–0001–0046#7.5

Step

Repair

1 After powering on, all LEDs are lit

1 Replace the CPU card

*2 Replace the MAIN BOARD

2 When the robot system software starts

1 Replace the CPU card

*2 Replace the MAIN BOARD

3 When the robot system starts, the CPU card

DRAM initialization is complete

1 Replace the CPU card

*2 Replace the MAIN BOARD

4 When the robot system starts, DRAM, SRAM initialization is complete

1 Replace the CPU card

*2 Replace the MAIN BOARD

*3 Replace the FROM/SRAM card

5 When the robot system starts, the communication IC initialization is complete

*1 Replace the MAIN BOARD

*2 Replace the FROM/SRAM card

6 When the robot system starts, the basic software loading is complete

*1 Replace the MAIN BOARD

*2 Replace the FROM/SRAM card

7 When the robot starts up and loads the basic software

*1 Replace the MAIN BOARD

*2 Replace the FROM/SRAM card

8 When the robot controller communicates with the TP teach pendant

*1 Replace the MAIN BOARD

*2 Replace the FROM/SRAM card

9 When the robot loads option software

*1 Replace the MAIN BOARD

2 Replace the process I/O board

10 When initializing DI/DO

*1 Replace the FROM/SRAM card

*2 Replace the MAIN BOARD

Step

Repair

11 SRAM preparation completed

1 Replace the axis control card

*2 Replace the MAIN BOARD

3 Replace the servo amplifier

12 Axis control card initialization completed

1 Replace the axis control card

*2 Replace the MAIN BOARD

3 Replace the servo amplifier

13 Calibration completed

1 Replace the axis control card

*2 Replace the MAIN BOARD

3 Replace the servo amplifier

14 Robot servo system powered

*1 Replace the MAIN BOARD

15 During program execution

*1 Replace the MAIN BOARD

2 Replace the process I/O board

16 During I/O operations

*1 Replace the MAIN BOARD

17 Initialization completed

Initialization ends normally

18 Robot normal

When the robot is normal, LED1 and LED2 will flash continuously

7-segment code

Fault description and countermeasures

Fault: RAM parity error on the CPU card

Measure 1: Replace the CPU card

Measure 2: Replace the MAIN BOARD

Fault: RAM parity error on the FROM/SRAM card

Measure 1: Replace the FROM/SRAM card

Measure 2: Replace the MAIN BOARD

Fault: Communication bus error

Measure 1: Replace the MAIN BOARD

Fault: Error in communication between the controller and the PANEL BOARD

Measure 1: Check the communication cable between the MAIN BOARD and the PANEL BOARD. If damaged, replace the communication cable

Measure 2: Replace the MAIN BOARD

Measure 3: Replace the PANEL BOARD

Fault: Servo alarm

Measure 1: Replace the servo control card

Measure 2: Replace the MAIN BOARD

Fault: System emergency stop alarm

Measure 1: Replace the servo control card

Measure 2: Replace the CPU card

Measure 3: Replace the MAIN BOARD

Fault description and countermeasures

Fault: ALM LED (red) lit indicates PSU alarm

Measure 1: Check the F4 (+24V) fuse on the PSU, if blown, replace it

Measure 2: Check the +5V, +15V, +24V voltages on the PSU and the related cables and devices connected to it. If damaged, replace them

Measure 3: Replace the PSU

Fault: PIL LED (Green) not lit, indicating 200V power supply to the PSU is missing

Measure 1: Check the F1 fuse on the PSU, if blown, replace it

Measure 2: Replace the PSU

LED

Fault and Countermeasures

RDY

Fault: This LED (GREEN) is not lit, indicating a communication interruption between the PANEL BOARD and MAIN BOARD

Measure 1: Check the communication cable between the MAIN BOARD and PANEL BOARD, if damaged, replace it

Measure 2: Replace the MAIN BOARD

Measure 3: Replace the PANEL BOARD

PON

Fault: This LED is not lit, indicating failure to convert +24V voltage to +5V voltage on the PANEL BOARD

Measure 1: Check the CRM63 connector, +24V input power

Measure 2: Replace the PANEL BOARD

LED

Fault and Countermeasures

Process I/O CA/CB/DA

Fault: Communication error between the MAIN BOARD and PROCESS I/O board

Measure 1: Replace the I/O board

Measure 2: Replace the MAIN BOARD

Measure 3: Replace the I/O communication cable

Process I/O CA/CB/DA

Fault: I/O board fuse blown

Measure 1: Replace the fuse

Measure 2: Check the peripheral cables

Measure 3: Replace the I/O board

LED

Color

Description

P5V

Green

Lit: Servo amplifier +5V power supply normal

Off: 1; Check the robot RP1 connection cable 2; Replace the servo amplifier

P3.3V

Green

Lit: Servo amplifier +3.3V power supply normal

Off: Replace the servo amplifier

SVEMG

Red

Lit: Robot has emergency stop signal input (if no emergency stop signal input, replace)

Off: Robot normal (if there is an emergency stop signal, replace the servo amplifier)

ALM

Red

Lit: Servo amplifier fault alarm

RDY

Green

Lit: Servo amplifier ready to drive motor

Off: If the motor can operate, replace the servo amplifier

OPEN

Green

Lit: Communication between the servo amplifier and MAIN BOARD normal

Off: 1; Check the communication cable between the servo amplifier and MAIN BOARD 2; Replace the servo control card 3; Replace the servo amplifier

WD

Red

Lit: 1; Replace the servo amplifier 2; Replace the servo control card

3; Replace the CPU card 4; Replace the MAIN BOARD

D7

Red

Lit: 1; Check the internal cables of the controller 2; Replace the emergency stop board

3; Replace the servo amplifier