2-50 Phaser 4400 Laser Printer Service ManualEngine Logic Board NVRAM Failure.(U6 NVM Fail/Power Off)There is problem with Non-Volatile RAM on the Engine Logic Board.4 1. Enter Service Diagnostics and select Motors/FansTests.2. Scroll to Fan Motor High Speed and press OK.Does the Fan rotate at high speed?Go to step 7. Go to step 5.5 1. Switch the printer power OFF.2. Remove the Left Interface Cover (RRP 1.1,page 6-6), Left Cover (RRP 1.2, page 6-7), and LeftPlate (RRP 1.11, page 6-16).3. Enter Service Diagnostics and select Motors/FansTests and press OK.4. Scroll to Fan Motor High Speed and press OK.5. On the LVPS, check the voltage between P/J283 pin1 and frame ground.Is the voltage +21.5 ±2.1 VDC?Replace theFanAssembly(RRP 9.1 onpage 6-87).Go to step 6.6 1. On the LVPS, check the voltage between P/J281 pin11 and frame ground.2. With the Fan Motor High Speed test still highlighted,press OK.Does the voltage change from 0.8 VDC to 0.0VDC when you press OK?Replace theLVPS (RRP9.5 onpage 6-91).Replace theEngine LogicBoard (RRP9.3 onpage 6-89).7 1. Switch the printer power OFF.2. Remove the Left Interface Cover (RRP 1.1,page 6-6), Left Cover (RRP 1.2, page 6-7), and LeftPlate (RRP 1.11, page 6-16).3. On the LVPS, check the voltage between P/J283 pin2 and frame ground.Is the voltage less than 1.0 VDC?Replace theEngine LogicBoard (RRP9.3 onpage 6-89).Replace theFanAssembly(RRP 9.1 onpage 6-87).NVM Failure Troubleshooting ProcedureStep Actions and Questions Yes No1 Switch the printer power OFF then ON.Does the error message reappear?Replace theEngine LogicBoard (RRP9.3 onpage 6-89).Go to step 2.2 To ensure that the problem is solved, switch the printerpower OFF and ON several times.Does the error message reappear?Replace theEngine LogicBoard (RRP9.3 onpage 6-89).Problemsolved.Fan Failure Troubleshooting Procedure (cont'd.)Step Actions and Questions Yes No
