4-84 Phaser 6180MFP Multifunction Printer Service ManualGeneral TroubleshootingDC Power Supply TroubleshootingLVPS Overcurrent Protection CircuitThis circuit stops all outputs if any of the Low Voltage Power Supply voltages3.3 VDC, 5 VDC, or 24 VDC are shorted.The circuit is reset when the short is removed, the power is turned Off, andthen On again.LVPS Overvoltage Protection CircuitThis circuit stops all outputs if the power supply voltage 3.3 VDC, 5 VDC, or24 VDC exceeds the specified voltage respectively. The operating point is 32VDC or less for 24 VDC, 7 VDC or less for 5 VDC, or 4.4 VDC for 3.3 VDC.The circuit is reset when the power is turned Off, and then On again after acertain time.LVPSTroubleshooting Reference TableApplicable Parts Wiring and Plug/Jack Map References■ LVPS, PL9.2.13■ LVPS Harness, PL10.1.3■ “Map 4 - LVPS and MCU Board” onpage 10-13■ “DC Power Supply” on page 10-24Troubleshooting Procedure TableStep Actions and Questions Yes No1 1. Perform the AC power supplytroubleshooting procedure (page 4-83).2. Does the problem persist?Go to step 2. Complete.2 1. Turn the AC power switch Off.2. Is the Fuse on the low-voltage powersupply board open?Replace theLVPS(page 8-83).Go to step 3.3 1. Disconnect the wiring harnessconnectors J501 and J502 from theLVPS.2. Turn the AC power switch On.3. Verify the DC voltages between thefollowing pins on the LVPS:■ P501-1 <=> P501-2 = +5 V■ P501-3 <=> P501-4 = +3.3 V■ P502-1 <=> P501-2 = +24 VGo to step 4. Replace theLVPS(page 8-83).
