2-48 Phaser 4400 Laser Printer Service ManualLaser Unit Failure.(U2 Laser Fail/Power Off)Laser Failure at warm-up: Transmitting /BD signal is longer than specified value for 10 sec. + t1. The laser power does not reach the specified value.Laser Failure after warm-up: Laser signal intervals become longer than the Fail time interval after Laserwarm-up is completed.Laser Failure Troubleshooting ProcedureStep Actions and Questions Yes No1 1. Enter Service Diagnostics and2. Select Engine NVRAM Adjustments.3. Scroll to Laser Power and press OK.Is the value for Laser Power set to ì10î?Go to step 2. Set the valueto 10. If theproblempersists,replace theEngine LogicBoard (RRP9.3,page 6-89).2 Select Motors/Fans Tests then Laser Scan Motor.Can you hear the Laser Scan Motor spin up?Go to step 3. Go to LaserAssembly onpage 3-17.3 1. Switch the printer power OFF.2. Remove the Left Interface Cover (RRP 1.1 onpage 6-6), the Left Cover (RRP 1.2 on page 6-7), andthe Left Plate (RRP 1.11 on page 6-16).3. Disconnect P/J21 from the Engine Logic Board.Switch the printer power-on.4. On the Engine Logic Board, check the voltagebetween P21-6 and frame ground.Is the voltage +5.0 VDC?Go to LaserAssembly onpage 3-17.Go to step 4.4 On the Engine Logic Board, check the voltage betweenP25 pin 4 and frame ground.Is the voltage +5.0 VDC?Go to step 6. Go to step 5.5 On the Engine Logic Board, check the voltage betweenP28 pin 7 and frame ground.Is the voltage +5.0 VDC?Replace theEngine LogicBoard (RRP9.3 onpage 6-89).Replace theLVPS (RRP9.5 onpage 6-91).6 On the Engine Logic Board, check the voltage betweenP25 pin 3 and frame ground.Is the voltage +5.0 VDC?Replace theEngine LogicBoard (RRP9.3 onpage 6-89).Go to Installor ReseatPrintCartridge. onpage 2-33.
