HP LaserJet M9040/M9050 Service Manual - Page 368

Sensor test This test manually activates the sensors on Tray 4 to test whether they are working correctly. 1. Set the DIP switches on the controller PCA for the sensor-test mode as shown on the diagnostics label inside the Tray 4 back cover. 2. For each paper sensor, perform the following actions: ● Pull open the paper tray. ● Remove the metal spring that holds the sensor unit in place (secured by one screw). ● Pull out the sensor unit. 3. To set the power-supply switch to the diagnostic mode, pull the blue power-supply switch outward. 4. To manually activate each sensor, press it in. ● When you activate the sensor, the bottom service LED on the controller PCA illuminates. When you release the sensor, the LED turns off. ● If the LED does not come on, a problem exists with the sensor. Replace the corresponding FRU. 5. To stop the test, return the power-supply switch to the operational mode, and set the DIP switches on the controller PCA to the off position (see table). Table 7-6 DIP switch settings DIP switch Normal Motor test Stand-alone running Sensor test test 1 Off On On Off 2 Off On Off Off 3 Off Off Off On 4 Off On On On NOTE: Make sure that you turn the power supply off and set all the DIP switches to the off position (normal settings) when you finish the diagnostics, or the unit will not work correctly. Then, replace the back cover. Light-pattern interpretation If Tray 4 is working correctly, it picks up media from the tray and feeds it to the product, and the bottom service light flashes regularly every 0.5 seconds. Table 7-7 Tray 4 light-pattern interpretation Long (1 sec.) Short (0.03 sec.) Error number and meaning Recommended action 3 1 66.11.01 lifter malfunction Lift the tray by hand to make sure that it lifts smoothly. Make sure that the paper-size plates are correctly installed (in the same corresponding slots) and are not bent. If 350 Chapter 7 Solve problems ENWW