HP 8550 Service Manual - Page 541

Note Note EN 7 Press each of the sensor levers or switches and note whether or not the LEDs light up. A change in the status of the LEDs indicates a properly functioning sensor or switch. Because it is not possible to check which sensor is malfunctioning when two sensor levers are pressed, press one at a time. 8 If an LED does not light up, this indicates that the corresponding switch or LED is malfunctioning. Test pick-up Use the side HCI test pick-up mode to watch the side HCI's operation and spot malfunctioning components. A test pick-up starts when the C-link is connected, the side HCI interlock switch (MS1) is pressed (see note below), the power is turned on, and the DIP switches are set as follows: SW201-1 On SW201-2 Off SW201-3 On SW201-4 Off The side HCI interlock switch is also referred to as the Deck Set Detection Switch. This test continues as long as there is paper in the side HCI. 1 Power the system off. 2 Connect a C-link cable between the printer and side HCI. 3 Remove the rear cover. 4 Set the DIP switches as follows: SW201-1 On SW201-2 Off SW201-3 On SW201-4 Off 5 Defeat the side HCI interlock switch so that the side HCI reads that it is attached to the printer. The side HCI interlock switch is also referred to as the Deck Set Detection Switch. 6 Load paper in the side HCI. Side HCI troubleshooting 539