• Code: U1
• Display: U1:MOTOR FAIL
• Description: There is a problem with the Motor Assy Main.
  1. The rotation speed of the Motor Assy Main is less than specified rpm and the state of a printer does not turn READY, after the Motor Assy Main started rotating 1.3 seconds passed.
  2. The fail is detected during the Fan on operation.
• Remedy: 1 INITIAL ANALYSIS Inspect the following components. • Motor Assy Main • PWBA HKB26 MCU • Gear Assy Drive • PWBA HKB PS Are they compatible with your printer version, correctly installed, not damaged, deformed, or contaminated? Go to step 2. Replace the problem components. 2 MOTOR ASSY MAIN ANALYSIS Use MAIN MOTOR TEST to check the Motor Assy Main . Does the Motor Assy Main run? Replace the PWBA HKB26 MCU . Go to step 3. 3 MOTOR ASSY MAIN ANALYSIS 1. Remove the Motor Assy Main from the Gear Assy Drive . Do not unplug the Motor Assy Main from the PWBA HKB26 MCU . 2. Use MAIN MOTOR TEST to check the Motor Assy Main. Does the Motor Assy Main run? Replace the Gear Assy Drive . Go to step 4. 4 MOTOR ASSY MAIN ANALYSIS Check the voltage between P/J291-9 <=> P/J291-6, P/J291-8 <=> P/J291-5 and P/J291-7 <=> P/J291-4. Is there +24VDC between P/J291-9 <=> P/J291-6, P/J291-8 <=> P/J291-5 and P/J291-7 <=> P/J291-4 on the Motor Assy Main? Replace the Motor Assy Main . Go to step 5. 5 PWBA HKB26 MCU ANALYSIS Check the voltage between P/J29-1 <=> P/J29-4, P/J29-2 <=> P/J29-5 and P/J29-3 <=> P/J29-6. Is there +24VDC between P/J29-1 <=> P/J29-4, P/J29-2 <=> P/J29-5 and P/J29-3 <=> P/J29-6 on the PWBA HKB26 MCU? Replace the PWBA HKB26 MCU . Go to step 6. 6 PWBA HKB PS ANALYSIS Check the voltage between P/J281-1 <=> P/J281-4, P/J281-2 <=> P/J281-5 and P/J281-3 <=> P/J281-6 on the PWBA LVPS Is there +24VDC between the each P/J281-1 <=> P/J281-4, P/J281-2 <=> P/J281-5 and P/J281-3 <=> P/J281-6 on the PWBA HKB26 MCU? Replace the PWBA HKB26 MCU . Replace the PWBA HKB PS

• Code: U2
• Display: U2:ROS FAIL
• Description: There is a problem with the ROS Assy.
  1. BD signal intervals are longer than specified value after ROS Motor start rotating.
  2. After the interval of transmitting /BD signal reaches the specified value, the interval is longer than the specified value.
  3. When the laser power does not reach the specified value.
• Remedy: 1 INITIAL ANALYSIS Inspect the following components. • ROS Assy • PWBA HKB26 MCU • PWBA HKB PS • CRU • Harness Assy ROS (J21-J211, J212, J213) • Harness Assy VDO (J22-J233) Are they compatible with your printer version, correctly installed, not damaged, deformed, or contaminated? Go to step 2. Replace the problem components. 2 NVRAM ANALYSIS Check the parameter using ADJUSTMENT MODE MENU. Is the parameters set correctly? Go to step 3. Set correct paramete.r 3 ROS MOTOR ANALYSIS 1. Check the ROS Motor using ROS MOTOR TEST. 2. If you cannot hear the ROS Motor running, unplug P/J29 (Motor Assy Main). Can you hear the ROS Motor running before the U2 code appears? Go to step 4. Go to 6.3 ROS Assy Failure. 4 LD DIODE ANALYSIS 1. Disconnect P/J22 and P/J21 on the PWBA HKB26 MCU . 2. Close the Cover Assy Front . 3. Switch ON Main Power. 4. Check the voltage between P21-5 and P21-6. Is there +5 VDC between P21-5 and P21-6? Go to 6.3 ROS Assy Failure. Go to 6.1 PWBA HKB PS Failure (+3.3 VDC).

• Code: U4
• Display: U4:FUSER FAIL
• Description: There is a problem with the Fuser Assy.
  1. Fuser Assy temperature is does not reach the temperature even after 110 seconds passed.
  2. Fuser Assy temperature gets lower than [SetTemp. 125 C], in printing.
  3. Fuser Assy temperature gets higher than [SetTemp. 220 C].
  4. The thermistor disconnection is detected.
  5. The heat lamp continuously turns on for 10 seconds during the Standby Mode.
• Remedy: 1 INITIAL ANALYSIS Inspect the following components. • Fuser Assy • Harness Assy Fuser-M (J271, J11, J27, J262) • PWBA HKB26 MCU • PWBA HKB PS • Switch Assy I/L Front • Switch Assy I/L Rear • Sensor Photo Exit in the Fuser Assy Are they compatible with your printer version, correctly installed, not damaged, deformed, or contaminated? Go to step 2. Replace the problem components. 2 SWITCH ASSY I/L FRONT ANALYSIS Check the Switch Assy I/L Front function using SENSOR/ SWITCH CHECH. Does the Switch Assy I/L Front function correctly and increment the Sensor Check number each time you actuate it? Go to step 3. Replace the Switch Assy I/ L Front 3 SWITCH ASSY I/L REAR ANALYSIS Check the Switch Assy I/L Rear function using SENSOR/ SWITCH CHECH. Does the Switch Assy I/L Rear function correctly and increment the Sensor Check number each time you actuate it? Go to step 4. Replace the Switch Assy I/ L Rear . 4 HARNESS ASSY FUSER-M (J271, J11, J27, J262) ANALYSIS Is there continuity between J271 and J11? Go to step 5. Replace the Harness Assy Fuser-M (J271, J11, J27, J262) . 5 HEATER ASSY ANALYSIS Does U4 appear after POWER–ON? (Answer YES if there is a momentary Fuser Assy Warm-Up Sequence) Go to 6.5 Temperature Sensor Failure. Go to step 6. 6 HEAT ROD ANALYSIS Let the Heat Rod cool down. Does the Heat Rod glow when power is switched ON? Go to step 6. Go to 6.4 Heat Rod Failure. 7 Does the Heat Rod switch ON and OFF after Power–On Sequence? Go to step 8. Go to step 9. 8 HEAT ROD ANALYSIS Is there proper VAC between P/J11-1 and P/J11-2? Go to 6.5 Temperature Sensor Failure. Replace the PWBA HKB PS . 9 PWBA HKB PS ANALYSIS Perform this check within 65 seconds after switching power ON. After specified seconds, PWBA HKB PS shuts down due to a no–load condition. Is there +3.3VDC between P/J281-10 and P/J28-8 on the PWBA HKB PS? Go to step 10. Go to 6.1 LVPS Failure (+3.3VDC). 10 HEAT ROD ACTUATOR SIGNAL ANALYSIS Disconnect P/J28 on the PWBA HKB26 MCU . Is there 0VDC between P/J 28-12 and P/J 28-8 on the PWBA HKB26 MCU during Power–ON sequence, and does the voltage rise to +3.3VDC when the sequence finishes? Go to 6.1 PWBA HKB PS Failure (+3.3 VDC). Replace the PWBA HKB26 MCU .

• Code: U5
• Display: U5:Fan AssyFAIL
• Description: There is a problem with the Fan Assy.
  1. The Fan Motor stops rotating after the printerpower is turned on.
• Remedy: 1 INITIAL ANALYSIS Inspect the following components. • Fan Assy • PWBA HKB26 MCU • PWB ESS Are they compatible with your printer version, correctly installed, not damaged, deformed, or contaminated? Go to step 2. Replace the problem components. 2 FAN ASSY ANALYSIS Can you hear or see the Fan Assy spinning when you power-on the printer? Go to step 3. Go to 6.16 Fan Assy Failure. 3 FAN ASSY SIGNAL ANALYSIS Check the voltage between P/J28-13 and P/J28-8 on the PWBA HKB26 MCU while the U5 code is displayed. Is there +3.3VDC between P/J28-13 and P/J28-8? Replace the Fan Assy . Replace the PWBA HKB26 MCU .

• Code: U6
• Display: U6:NVM FAIL
• Description: There is a problem with NVRAM.
  1. An NVRAM read error occurred immediately when you switched ON main power.
  2. A write error occurred when you tried to write toNVRAM.
  3. The overflow of the Task Table.
• Remedy: 1 INITIAL ANALYSIS Inspect the following component. • PWBA HKB26 MCU Is it compatible with your printer version, correctly installed, not damaged, deformed, or contaminated? Go to step 2. Replace the problem component. 2 Does U6 appear after you switch ON Main Power? Go to step 5. Problem corrected. 3 Switch Main Power OFF and ON several times. Does U6 still appear when you switch ON Main Power again? Go to step 4. Problem solved. 4 PWBA HKB26 MCU ANALYSIS Enter DIAGNOSTIC MODE MENU. Can you enter DIAGNOSTIC MODE MENU? Go to step 5. Replace the PWBA HKB26 MCU . (If U6 continues, go to 6.20 Electrical Noise). 5 NVRAM ANALYSIS Enter ADJUSTMENT MODE MENU and check the parameters for each value of NVRAM Code. Are all parameters set correctly? Replace the PWBA HKB26 MCU . Go to step 6. 6 PWBA HKB26 MCU ANALYSIS 1. Enter correct parameters. 2. Switch OFF Main Power. 3. Switch ON Main Power. Does U6 still appear? Replace the PWBA HKB26 MCU . Problem solved. Return to Service Flowchart.