2 For each paper sensor: a Open the paper tray and the VTU on the 2,000-sheet input unit. b Remove the metal spring that holds the sensor unit in place (secured by 1 screw) (see figure 161, callout 2, and figure 163, callout 2). 3 Use the switch that is located on the unit’s power supply to switch to diagnostic mode. c Pull out the sensor unit. 4 Manually activate the sensor. • When you activate the sensor, the bottom service LED on the controller PCA comes on. When you release the sensor, the LED goes off. • If the LED does not come on, there is a problem with the sensor. Replace the corresponding field replaceable unit.
5 To stop the test, turn the power supply switch back to operational mode and set the DIP switches on the controller PCA to the off position. 476 Chapter 7 - Troubleshooting EN