HP 4550 Service Manual - Page 305

Note The paper path test allows the service technician to verify the operation of components within the paper path. When the test is initiated both the M1 and M2 are activated. You will see the ITB lift cams rotate once and the ITB drive gear turn briefly. The remaining portion of the test simply allows both the M1and M2 to run, thus exercising the gears and rollers associated with them. If an error occurs during the paper path test, the message PATH_1PAPER PATH TEST FAILED appears. Developer test The developer test rotates the carousel stopping at each toner cartridge and rotating the developer sleeve. For the best view of the carousel and the toner cartridge sleeves, remove the drum cartridge. The drum drawer must be closed before the test can run. 1 Press the [ITEM] key until ENGINE DIAGS DEVELOPER TEST appears. 2 Press the [SELECT] key to run the test. The front panel will display ENGINE DIAGS E2:DEVELOPER while the test is running. Watch the carousel and make sure the toner cartridge developer sleeve rotates. The sequence will be black followed by a pause, then magenta, cyan, and finally yellow. The test will last for approximately 35 seconds. While the developer test is running you will see the drum turn if it is installed, as well as the drive gear for the ITB. Drum test The drum test exercises the drum drive mechanism. Also, the fuser motor is turned on to allow the lift cams for the ITB to be rotated into the ITB up position. 1 Press the [ITEM] key until ENGINE DIAGS DRUM TEST appears. 2 Press the [SELECT] key to run the test. The front panel will display ENGINE DIAGS E3:DRUM while the test is running. Watch to see if the ITB lift cams turn and if both the drum drive gear and the ITB drive gear are rotating. Path sensors test The path sensors test allows the paper path sensors and switches to be tested for correct operation. Table 7-29 shows the correlation between the identifier on the front panel and the sensor or switch it represents. Table 7-29 Paper path sensors and switches Identifier Name Description A PS8 Tray 2 paper detect sensor B PS3 Tray 1 last sheet of media pulled sensor C PS4 Tray 1 paper detect sensor D SW801 Tray 2 paper size switch 2 E SW802 Tray 2 paper size switch 1 F SW803 Tray 2 paper size switch 0 G PS3001 Optional Tray 3 paper detect sensor H SW3001 Optional Tray 3 paper size switch 2 I SW3002 Optional Tray 3 paper size switch 1 J SW3003 Optional Tray 3 paper size switch 0 K PS10 Carousel position sensor C7085-90921 Chapter 7 Troubleshooting 303