Phaser 6121MFP Service Manual 3-77Error Messages and Codes0300 Laser Motor Failure and 0310 Laser Unit FailurePossible causes:• The Polygon Motor does not rotate evenly even after the lapse of a givenperiod of time after it has been started.• The motor lock signal remains HIGH for a given period of consecutive timewhile the Polygon Motor is being rotated.• The SOS signal is not detected within a given period of time after the outputof the laser has been started.Initial ActionsPower down and reboot the printer.Procedure4 Check the 2nd Image TransferRetraction Position Solenoid for properdrive coupling and correct asnecessary.Does the problem persist?Go to step 5. Complete.5 Check the 2nd Image TransferRetraction Position Sensor controlsignal for a voltage change at P/J12-3on the Engine Control Board.Is the signal operating correctly?Go to step 6. Replace theEngine ControlBoard(page 8-59). Ifthe problempersists, go tostep 6.6 Replace the 2nd Image TransferRetraction Position Solenoid.Does the problem persist?Go to step 7. Complete.7 Replace the 2nd Image TransferRetraction Position Sensor.Complete.Troubleshooting Reference TableApplicable Parts Wiring and Plug/Jack References■ Laser Unit, PL4.0.13■ Engine Control Board, PL13.0.20■ Power Supply, PL13.0.17■ Board Locations (page 2-10)■ Map 1 - Engine Control BoardPlug/Jack Locator (page 10-5)■ Engine Control Board Wiring(page 10-14)Troubleshooting Procedure Table (continued)Step Action and Questions Yes No
