• Code: U1-2320
• Display: Fuser Unit Failure: #U1-2320. Turn off then on
• Description: The fuser unit is not installed or AC is not supplied to the Heat Lamp. Thermistor is defective.
• Remedy: 1. Check if the fuser unit is installed properly. Turn the machine off then on. 2. Remove the fuser unit. Remove the COVER-UPPER. And measure the thermostat continuity. Check if the thermostat is opened. 3. Measure the LAMP-HALOGEN resistance value from the center and both sides. Check if it has the continuity. 4. Check if 2 thermistor connectors are connected properly. 5. Remove the thermistor. Check if the thermistor has curled as shown below. If there is any contamination on the fi lm, clean it. Caution - Be careful not to be scratched or curled the film. 6. Check if the thermistor connector on the engine board is connected properly. 7. Check if the FDB connector is connected properly. 8. Check if the voltage in user environment is in this range (80V - 140V, 160V - 260V). 9. Replace the FDB. If the problem persists, replace the engine board.

• Code: U1-2330
• Display: Fuser Unit Failure: #U1-2330. Turn off then on
• Description: Low Heat error has occurred. The fuser unit can not reach the target temperature within normal time.
• Remedy: 1. Check if the fuser unit is installed properly. Turn the machine off then on. 2. Remove the fuser unit after removing 4 screws. 3. Check if the fuser unit is overheated. a. Remove the GUIDE-EXIT LOWER. To remove it, fi rst, push and release the green lever to the direction of arrow. Then, lift and pull it. b. Rotate the gear to direction of arrow and check the surface of the Hear roller and Pressure roller. If there is any overheated traces, replace the fuser unit. c. Remove the COVER-UPPER. Check if the thermistor harness is connected properly and the thermistor is defective. 4. Remove the thermistor. Check if the thermistor has curled as shown below. If there is any contamination on the fi lm, clean it. Caution - Be careful not to be scratched or curled the film. 5. Check if the center/side lamp is assembled properly. a. To remove the COVER-DUPELX, Remove 1 screw. Lift up the COVER-DUPLEX PATH to the direction of arrow slightly. b. Release the both hooks with the tweezers or (-) driver. c. Check if the lamp harness and harness are connected properly. (white-white , color-color) * Reassemble the fuser unit. Turn the machine off then on. If the problem persists, go to the next step. 6. Check if the thermistor connector on the engine board is connected properly. 7. Check if the FDB connector is connected properly. 8. If there is no problem, upgrade the latest fi rmware.

• Code: U1-2340
• Display: Fuser Unit Failure: #U1-2340. Turn off then on
• Description: The overheat error has occurred.
• Remedy: 1. Check if the fuser unit is installed properly. Turn the machine off then on. 2. Remove the fuser unit after removing 4 screws. 3. Check if the fuser unit is overheated. a. Remove the GUIDE-EXIT LOWER. To remove it, fi rst, push and release the green lever to the direction of arrow. Then, lift and pull it. b. Rotate the gear to direction of arrow and check the surface of the Hear roller and Pressure roller. If there is any overheated traces, replace the fuser unit. c. Remove the COVER-UPPER. Check if the thermistor harness is connected properly and the thermistor is defective. 4. Remove the thermistor. Check if the thermistor has curled as shown below. If there is any contamination on the fi lm, clean it. Caution - Be careful not to be scratched or curled the film. 6. Measure the thermostat resistance. Check if the thermostat is opened. Although the thermostat is opened, check the following steps. And then replace the fuser unit. 7. Remove the FDB cover. Check if the FDB Triac is short. Check the resistance among 3 legs of both transistors. If it is short, replace the FDB. 8. If there is no problem for above steps, repalce the FDB, engine board step by step. If the fuser unit is defective, replace it.

• Code: U2-1111
• Display: LSU Unit Failure: #U2-1111. Turn off then on
• Description: LSU motor does not work normally. 1. Harness connection error. 2. LSU is defective. 3. Main board is defective.
• Remedy: Check the followings. 1. Execute the LSU motor test in EDC mode. Check LSU motor operation sound. 2. If there is no sound, remove the right cover. Check if the C9 or C10 connector is connected properly 3. It it is OK, remove the top cover. Check if the LSU connector is connected properly. 4. Check if the LSU harness is defective. 5. Reconnect the LSU harness and then execute the LSU motor test again. 6. Replace the LSU. 7. If the problem persists, replace the main board.

• Code: U2-1113
• Display: LSU Unit Failure: #U2-1113. Turn off then on
• Description: LSU LD(Laser Beam Detect) signal is abnormal. 1. Harness connection error. 2. LSU is defective. 3. Main board is defective. 4. Engine board is defective.
• Remedy: 1. Check if the C9 or C10 connector on the main board is connected properly. 2. Check if the LSU harness is defective. 3. Check if the LSU connector is connected properly. Reconnect it. 4. Turn the machine off then on. 5. If the problem persists, replace the LSU. 6. If the problem persists after replacing the LSU, remove the main board. 7. If the problem persists after replacing the main board, remove the engine board. 8. If you have the DVM, measure the voltage level for LD optical power control before step 5. If it is normal, the value is between 0.6V-2.0V. If the value is less than 0.5V, check the FFC cable between engine and main board. Replace the FFC cable.