HP 4550 Service Manual - Page 236

Table 7-3 Numerical printer error messages (continued) carousel housing pass through PS10 to provide positioning information. The black toner cartridge tab Note is the home position. Toner cartridge position within the carousel is monitored by PS11. If PS11 fails or is improperly connected, a 54.2 error appears. Another The printer CANNOT operate with the top cover removed unless the carousel brake has been released or removed. indicator of this is that the carousel starts to rotate 3. Verify the carousel drive motor wiring harness then stops immediately. is firmly seated into connector J203 of the A 54.2 error message can also occur if the sensor is developing PCB (see Figure 7-38). installed backwards. 4. Verify PS10 (refer to Figure 7-31) is working correctly and not excessively dirty (clean if necessary) and that the wiring harness is firmly seated into both the sensor assembly and connector J206 of the developing PCB. 5. Verify PS11 is connected and functioning properly. 6. Verify all connectors to the developing PCB and the DC controller PCB are firmly seated. 7. Verify that the rotary drive assembly is working. Replace it on older units with more than 50K of life. Note The following URL provides help with cartridge installation and removal: http://www.hp.com/go/ ljsupplies. 54.3 PRINTER ERROR Description: Action: The printer is not receiving data back from the 1. density sensor (PS14). PS14 is located in the bottom of the imaging drum drawer (refer to Figure 7-30). During calibration routines, a series of images are written on the imaging drum and the 2. densitometer measures the density of the image (e.g. amount of toner that is placed into the drum). These measurements provide the feedback to ensure image quality is consistent throughout the life of the consumable. Verify the densitometer is clean; perform the toner density sensor cleaning procedure in Chapter 7 of the online user guide. Inspect the density sensor wiring harness for damage. The harness runs from the density sensor through the left-side upper control arm of the imaging drum drawer to J1010 of the DC controller PCB. Verify that the cable is firmly seated into the J1010 of the DC controller PCB. 3. If the error persists, replace the density sensor assembly. 54.4 PRINTER ERROR Description: Optional equipment is not recognized. Action: Turn the printer off and on to reset the printer. 54.5 PRINTER ERROR Description: Indicates a waste toner sensor malfunction. Action: 1. Turn the printer off and on to reset the printer. 2. Remove the drum cartridge and clean the waste toner detection window with a dry cloth. 3. Clean the waste toner sensor unit at the printer side with a dry cloth. 4. Check the light guide and clean it if necessary. Replace the light guide if the ends are scarred. 5. Reconnect the waste toner sensor unit connector and the DC controller PCB connector (J1009) correctly. 6. Replace the waste toner sensor (PS13). 234 Troubleshooting C7085-90921