HP Color LaserJet 8500 Service Manual - Page 422

Service mode engine diagnostics Engine diagnostics can be used to perform mechanical tests on the print engine and its related components to help pinpoint components in the printer that need replacement or repair. WARNING! Take care when you use engine diagnostics - some tests require door interlocks to be defeated, and defeating interlocks can expose potential hazards in the engine. High-voltage supplies and the laser are shut down whenever the printer is in diagnostic mode. However, any defeating of interlocks without entering the engine diagnostic mode results in potential exposure to the laser and high voltages. CAUTION Entering the Service Mode Menu 1 From a READY state, press MENU until SERVICE MENU appears. 2 Press ITEM - (the left side of the key) and VALUE - simultaneously. For a menu map of the Service Mode Menu, see page 93. Paper path test The paper path test simulates a page moving through the paper path from input trays 1, 2, and 3 to the output bins. Removing some engine parts (such as the transfer drum) prevents paper from feeding completely. It is possible to select the input and output trays for the test by indicating in the Paper Path Menu which input tray and output bins should be accessed (by selecting ON or OFF). Multiple input trays can be selected, but only a single output can be selected. A page is fed from each input tray to the selected output. If a jam occurs during the test, the test should continue with the next input tray in the list. Jam detection is OFF in this mode and an unattended test might result in damage to the printer. 420 Chapter 7 - Troubleshooting EN