4-44 Phaser 4500/4510 Service ManualGeneral Troubleshooting3 Check the low paper sensor (2)1. Install the optional 550-sheet feeder(page 8-86).2. Remove the 550-sheet paper cassette.3. Measure the voltage across P/J81-3 <=>P/J81-2 while manually operating the lowpaper actuator.Is the voltage 3.3 VDC when the low paperactuator is held up, and 0 VDC whenreleased?Go to“Optional550-SheetFeeder PWBA(Tray 3)” onpage 4-39, or“Optional550-SheetFeeder PWBA(Tray 4)” onpage 4-40.Go to step 4.4 Check the low paper sensor harness:1. Install the Optional 550-Sheet Feeder(page 8-86).2. Disconnect P/J810 from the low papersensor.3. Disconnect P/J81 from the 550-sheetfeeder PWBA.4. Test J81 <=> J810 for continuity.Are all conductors continuous?Go to step 5. Replace thelow papersensorharness.5 Check the HVPS/engine logic board:1. Disconnect P/J11 and P/J20 from theHVPS/engine logic board.2. Test P11-16 <=> P20-5 for continuity.Is it continuous?Go to step 6. Replace theHVPS/enginelogic board(page 8-73).6 Replace low paper sensor (page 8-34).Does the problem still occur afterreplacement?Replace theHVPS/enginelogic board(page 8-73).Problemsolved.Troubleshooting Procedure (continued)Steps Actions and Questions Yes No
