HP 4550 Service Manual - Page 304

Engine diagnostics Engine diagnostics access portions of the printer's internal diagnostics that occur when the printer is turned on. These diagnostics are available as tools to help isolate problems that are not reported by the firmware. As mentioned previously, no error message will appear if there is a problem in the section being tested. A good understanding of how the printer operates is required to use the engine diagnostics successfully. To have a better view of the areas being exercised, remove the left side cover and the ITB drawer. Defeat the two ITB drawer switches (SW 1 and SW 4) located on the left-side of the drawer cavity. Now you can run the diagnostics and watch the assemblies as they are operated. Listed below in (Table 7-28) are the diagnostics available and a brief description of what each diagnostic will do. A detailed explanation for each diagnostic can be found under its own heading later in this document. Table 7-28 Engine diagnostics Menu Item Selectable Value Description CONTINUOUS N (default) Y Selected test will run once. Selected test will run in a continuous loop. In the 4550 series only, [CANCEL JOB] will abort the test. PAPER PATH TEST Turns on the motors that control the paper path section of the printer. In the 4550 series only, [CANCEL JOB] will abort the test. DEVELOPER TEST Rotates the carousel and the developers. In the 4550 series only, [CANCEL JOB] will abort the test. DRUM TEST Turns on the drum drive motor that drives the drum and ITB. In the 4550 series only, [CANCEL JOB] will abort the test. PATH SENSORS Displays the state for each of the paper path sensors and switches. In the 4550 series only, this test will continue running until the [CANCEL JOB] key is pressed. DOOR SENSORS Displays the state for each of the door and drawer switches. In the 4550 series only, this test will continue running until the [CANCEL JOB] key is pressed. Paper path test 1 Press the [ITEM] key until you see ENGINE DIAGS PAPER PATH TEST. 2 Press the [SELECT] key to activate the test. While the test is running you will see ENGINE DIAGS E1:PAPERPATH displayed in the front panel. The test takes approximately 15 seconds to run. Components exercised by the paper path test include the fusing motor (M1), paper path pick-up motor (M2), and associated gears and assemblies. The paper pick up roller for tray 2 can be activated by manually activating the paper pick solenoid (SL2). This test will not pick up paper and move it through the paper path. To test this function, simply run a configuration page. For multiple pages, select continuous configuration page in the control panel. 302 Troubleshooting C7085-90921