3-14 Phaser 4400 Laser Printer Service ManualPower Supply5 Replace the Engine Logic Board (RRP 9.3 onpage 6-89).Does the problem still appear?Go to step 6. Problemsolved.6 Notify customer the cause of the trouble seems to be acommunication problem between the host computerand the printer. The customer should contact CustomerSupport.Power Supply Troubleshooting ProcedureStep Actions and Questions Yes No1 1. Switch the printer power OFF.2. Disconnect the power cord.3. Remove the Left Interface Cover (RRP 1.1 onpage 6-6), Left Cover (RRP 1.2 on page 6-7), and theLeft Plate (RRP 1.11 on page 6-16).4. Disconnect the following from the LVPS: P/J281 (Engine Logic Board) (RRP 9.3, page 6-89) P/J282 (Image Processor Board) (RRP 9.2 onpage 6-88) P/J11 (Fuser) (RRP 6.2 on page 6-66) P/J283 (Main Fan) (RRP 9.1, page 6-87) P/J284 (Front Interlock Switch) (RRP 9.9,page 6-96) P/J1 (5 VDC Power Supply) (RRP 9.4, page 6-90)5. Connect the power cord.6. Switch the printer power ON and measure thevoltages listed here on the LVPS.Are all voltages correct?Go to step 2. Replace theLVPS (RRP9.5 onpage 6-91).2 1. Switch the printer power OFF.2. Reconnect P/J281 to the LVPS.3. Switch the printer power ON and measure thevoltages listed in step 1.Are all voltages correct?Go to step 3. Go to step 4.3 1. Switch the printer power OFF.2. Reconnect one of the plugs disconnected in step 1.3. Switch the printer power ON.4. Measure the voltages listed in step 1.Are all voltages correct?Repeat thestep with thenextdisconnectedplug.Replace thecomponentjustconnected tothe LVPS.Erratic Printer Operation Troubleshooting Procedure (cont'd.)Step Actions and Questions Yes NoRed Lead Black Lead VoltageP/J281 pin 7 Frame Ground +5.0 VDCP/J281 pin 10 Frame Ground +3.3 VDCP/J281 pin 1 Frame Ground +24.0 VDC
