• Code: 929.00, 929.66, 929.67
• Description: 929 .00 Toner sensor error—a problem has been detected with the toner sensor 929 .66 An error has been detected. No home windows has been detected. • Check toner cartridge. • Check toner sensor 929 .67 No toner sensor transition. • Check toner sensor • Check toner cartridge
• Remedy: 1 Developer drive assembly Incorrect operation of the developer drive assembly can cause the printer to display a 929.xx error code (Toner Sensor). Check the developer drive assembly for correct installation or, 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 (J15), 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 J15 on the system board. Check the voltage at J15-11. It reads approximately +5 V dc. If incorrect, replace the system board. If correct, check the voltage at J15-12. 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 J15-13 on the system board and pin 3 on the toner sensor results in a 929 service error.

• Code: 930.00...936.00
• Description: 930 .00 An incorrect printhead has been detected Check the printhead 932 .00 Printhead lost HSYNC. • Check printhead • Check cables and connections • Check system board 933 .00 Mirror motor locked, no first HSYNC received. • Check printhead • Check cables and connectors • Check system board. 934 .00 Mirror motor lost lock • Check printhead • Check cables and connections • Check system board 936 .00 Mirror moor not up to speed • Check printhead • Check system board
• Remedy: 1 Error code 931.xx 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 J2 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 J2-7 measures approximately +24 V dc. If incorrect, replace the system board. If correct, replace the printhead assembly. See “Printhead removal”. 2 Error Code 934.xx 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. The voltage at J5-2 measures approximately +24 V dc. If incorrect, replace the system board. If correct, replace the FRUs in the following order: • System board. See “System board and inner shield removal— model X642e” or “System board and inner shield removal —models X644e/X646e”. • Printhead assembly See “Printhead removal”.

• Code: 936.10...936.91
• Description: 936 .10 No hall effect detected at motor start. Motor is type 0. 936 .11 No hall effect detected at motor start. Motor is type 1. 936 .20 Failed to stop within timeout, motor is type 0. 936 .21 Failed to stop within timeout, motor is type 1. 936 .30 No lock detected at motor start for motor ID. Motor is type 0. 936 .31 No lock detected at motor start for motor ID. Motor is type 1. 936 .60 No lock detected at normal motor start. Motor is type 0. 936 .61 No lock detected at normal motor start. Motor is type 1. 936 .9 Stall detected during speed control. Motor is type 0. 936 .91 Stall detected during speed control. Motor is type 1.
• Remedy: 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 J20-6 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 gear does not turn, no 936 error code or 201.xx Paper Jam user message displays. Check the voltages at J20 on the system board. If the voltage is incorrect, replace the FRUs in the following order: • Main drive motor assembly • System board

• Code: 937
• Description: 937 .4 Overspeed detected during speed control. Motor is type 0. 937 .41 Overspeed detected during speed control. Motor is type 1. 937 .5 Overspeed detected during position control. Motor is type 0. 937 .51 Overspeed detected during position control. Motor is type 1. 937 .7 Loss of lock detected by higher level code. Motor is type 0. 937 .71 Loss of lock detected by higher level code. Motor is type 1. 937 .80 Driver over temperature detection. Motor is type 0.
• Remedy: 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 J20-6 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 gear does not turn, no 936 error code or 201.xx Paper Jam user message displays. Check the voltages at J20 on the system board. If the voltage is incorrect, replace the FRUs in the following order: • Main drive motor assembly • System board

• Code: 939.00
• Description: RIP–engine communications lost. System board
• Remedy: POR the printer several times, if the error code continues to be displayed, replace the system board

• Code: 940.00
• Description: LVPS zero-crossing test failed. • Incorrect LVPS installed • Noisy AC power source • LVPS to system board cable loose
• Remedy: Check to make sure the correct LVPS assembly has been installed. If the correct supply is installed, check to make sure the LVPS to system board cable is installed correctly. If correct, replace the LVPS assembly.

• Code: 947.00
• Description: PQET RAM test incomplete, PQET RAM test did not complete, PQET RAM test failed MARCH0 PQET RAM test failed MARCH1 PQET RAM test busy failure. PQET failed to pass RAM tests on the system board
• Remedy: Replace the system board.

• Code: 948.00
• Description: Pel clock check failed System board
• Remedy: Replace the system board.