• Code: 923
• Description: Fuser Error
• Remedy: Fuser is too hot during printing or when printer is idle. 1 Fuser lamp (incorrect lamp/ 925 Service Error) Install the correct voltage and wattage lamp or fuser assembly. See “Fuser assembly removal”. If the correct fuser lamp is installed and the 925 error remains, the fuser may have reached standby temperature too quickly. Check that the line voltage is not exceeding the maximum rating for the printer. 2 Fuser lamp fuser top cover assembly Observe the lamp through the left side frame. If the lamp does not come on, do the following: • Remove the redrive assembly. • Remove the fuser assembly, disconnect the LVPS to fuser AC cable from the fuser assembly, and remove the fuser. See “Fuser assembly removal” • Verify that the lamp is installed correctly. If correct, check the continuity of the fuser top cover assembly by verifying the lamp contacts on the right contact assembly. If incorrect, check continuity of the fuser lamp. If incorrect, replace the lamp. If correct, replace the fuser top cover assembly. 3 LVPS LVPS to fuser AC cable CAUTION: When taking measurements for AC power, observe all safety precautions. Measure the AC line voltage between the two connectors on the fuser end of the LVPS to fuser AC cable. If the voltage is incorrect, turn the power off, and remove the LVPS. Measure the AC line voltage between pins CN1-1 and CN1-3 on the board. If correct, check the continuity of the LVPS to fuser AC cable. If incorrect, replace the cable. If the AC line voltage at CN1 is incorrect, check fuse F2. If the fuse is blown, replace the fuse. If the fuse is not blown, replace the LVPS assembly.

• Code: 924
• Description: Fuser Error
• Remedy: An open circuit has been detected in the Fuser Thermistor Circuit. 1 Fuser lamp (incorrect lamp/ 925 Service Error) Install the correct voltage and wattage lamp or fuser assembly. See “Fuser assembly removal”. If the correct fuser lamp is installed and the 925 error remains, the fuser may have reached standby temperature too quickly. Check that the line voltage is not exceeding the maximum rating for the printer. 2 Fuser lamp fuser top cover assembly Observe the lamp through the left side frame. If the lamp does not come on, do the following: • Remove the redrive assembly. • Remove the fuser assembly, disconnect the LVPS to fuser AC cable from the fuser assembly, and remove the fuser. See “Fuser assembly removal” • Verify that the lamp is installed correctly. If correct, check the continuity of the fuser top cover assembly by verifying the lamp contacts on the right contact assembly. If incorrect, check continuity of the fuser lamp. If incorrect, replace the lamp. If correct, replace the fuser top cover assembly. 3 LVPS LVPS to fuser AC cable CAUTION: When taking measurements for AC power, observe all safety precautions. Measure the AC line voltage between the two connectors on the fuser end of the LVPS to fuser AC cable. If the voltage is incorrect, turn the power off, and remove the LVPS. Measure the AC line voltage between pins CN1-1 and CN1-3 on the board. If correct, check the continuity of the LVPS to fuser AC cable. If incorrect, replace the cable. If the AC line voltage at CN1 is incorrect, check fuse F2. If the fuse is blown, replace the fuse. If the fuse is not blown, replace the LVPS assembly.

• Code: 925
• Description: Fuser Error
• Remedy: Wrong fuser lamp installed. 1 Fuser lamp (incorrect lamp/ 925 Service Error) Install the correct voltage and wattage lamp or fuser assembly. See “Fuser assembly removal”. If the correct fuser lamp is installed and the 925 error remains, the fuser may have reached standby temperature too quickly. Check that the line voltage is not exceeding the maximum rating for the printer. 2 Fuser lamp fuser top cover assembly Observe the lamp through the left side frame. If the lamp does not come on, do the following: • Remove the redrive assembly. • Remove the fuser assembly, disconnect the LVPS to fuser AC cable from the fuser assembly, and remove the fuser. See “Fuser assembly removal” • Verify that the lamp is installed correctly. If correct, check the continuity of the fuser top cover assembly by verifying the lamp contacts on the right contact assembly. If incorrect, check continuity of the fuser lamp. If incorrect, replace the lamp. If correct, replace the fuser top cover assembly. 3 LVPS LVPS to fuser AC cable CAUTION: When taking measurements for AC power, observe all safety precautions. Measure the AC line voltage between the two connectors on the fuser end of the LVPS to fuser AC cable. If the voltage is incorrect, turn the power off, and remove the LVPS. Measure the AC line voltage between pins CN1-1 and CN1-3 on the board. If correct, check the continuity of the LVPS to fuser AC cable. If incorrect, replace the cable. If the AC line voltage at CN1 is incorrect, check fuse F2. If the fuse is blown, replace the fuse. If the fuse is not blown, replace the LVPS assembly.

• Code: 927
• Description: Fan stalled
• Remedy: This is an indication that a printer fan has stalled. 1 Main fan Manually spin the fan and check that it rotates freely. Check the cable connection to the system board, J7 for correct installation. 2 Main fan to system board cable Check the continuity of the cable. If incorrect, replace the cable. 3 Error code 927 (fan runs) Check the voltage at J7-1 on the system board. The voltage measures +5 V dc (static) 0 V dc (fan running). If incorrect, replace the main fan. If this does not fix the problem, replace the system board. 4 Error code 927 (fan not running) Check the voltage at J7-3 on the system board. The voltages are: • +22 V dc to +24 V dc (printer and fan running) • +12 V dc to +15 V dc (printer not running—fan running about half speed). If incorrect, replace the system board. If this does not fix the problem, replace the main fan.

• Code: 929
• Description: Toner Sensor
• Remedy: The toner sensor is not operating properly, the developer drive assembly is not operating properly or the print cartridge is defective. 1 Developer drive assembly Incorrect operation of the developer drive assembly can cause the printer to display a 929 error code (Toner Sensor). Check the developer drive assembly for correct installation, any sign of worn, loose, or broken parts. 2 Front harness cable Check the toner sensor portion of the front harness cable to make sure it is properly seated into the toner sensor. If correct at both the sensor and system board (J22), check the continuity of the cable. If incorrect, replace the cable. 3 Toner sensor The toner sensor cable is part of the front harness and part of connector J22 on the system board. Check the voltage at J22-11. It reads approximately +5 V dc. If incorrect, replace the system board. If correct, check the voltage at J22-12. It reads approximately +5 V dc with the system board removed from the printer. If incorrect, replace the system board. If correct, replace the toner sensor assembly. A bad ground connection between J22-13 on the system board and pin 3 on the toner sensor results in a 929 service error.

• Code: 930
• Description: Printhead Error
• Remedy: The wrong printhead is installed. Replace with the correct printhead.

• Code: 931 ... 935
• Description: Printhead Error 932 - Printhead: Lost Hsync 933 - Mirror Motor Locks/Lost Hsync 934 - Mirror Motor Lost Lock 935 - Mirror Motor unable to reach operating speed.
• Remedy: These errors represent a problem with the printhead. 1 Error code 931 No first HYSNC Signal Error Code 932 Lost HYSNC These errors usually indicate a failure in the HYSNC signal to the printhead. Check the continuity of the cables connected to J5 and J4 on the system board. If incorrect, replace the defective cable. The voltage at J4-1 measures approximately +5 V dc. If incorrect, replace the system board. The voltage at J5-7 measures approximately +24 V dc. If incorrect, replace the system board. If correct, replace the printhead assembly. 2 Error Code 934 Mirror motor lost lock Error Code 935 Mirror motor unable to reach operating speed These error codes indicate a problem with the mirror motor circuit in the printhead assembly or the mirror motor cable to the system board cable or system board assembly. Check the continuity of the mirror motor cable connected to J5 on the system board. If incorrect, replace the cable. The voltage at J5-7 measures approximately +24 V dc. If incorrect, replace the system board. If correct, replace the FRUs in the following order: • System board • Printhead assembly

• Code: 936 ... 937
• Description: 936 - Main Drive Motor initial lock failure 937 - Main Drive Motor lost lock
• Remedy: Indicates a problem with the main drive motor. 1 Main drive assembly (excessive noise or vibration) Remove the controller board and run a Diagnostic Print Test in the continuous mode. Check the main drive assembly for any excessive noise or vibration. Determine if the noise is in the main drive, toner cartridge, fuser, or main drive gearbox. Look for any loose or worn parts in the developer drive assembly, main drive gearbox, or fuser. Repair as necessary. 2 Main drive motor assembly (excessive noise, gears ratcheting and so on) A service error code 936 - Transport Motor may be displayed. Check the voltage at J24-6 on the system board. It measures approximately +5 V dc when the motor is not running and goes to 0 V dc when the motor is running. If incorrect, replace the system board. If this does not fix the problem, replace the main drive motor. 3 Main drive motor cable Check the continuity of the main drive motor cable. If incorrect, replace the cable. 4 Motor does not turn, no gear error code 936 or user message 201 Paper Jam displays. Check the voltages at J24 on the system board. If the voltage is incorrect, replace the FRUs in the following order: • Main drive motor assembly • System board