Lexmark T522 Service Manual - Page 130

4520-xxx Toner Sensor Service Check Service Tip: Check the print darkness MENU setting before checking the toner sensor. This service check is intended to be used when a 929 Service Error displays. FRU 1 Developer Drive Assembly 2 Front Harness Cable 3 Toner Sensor Action Incorrect operation of the developer drive assembly can cause the printer to display a 929 error code (Toner Sensor). Check the developer drive assembly for correct installation, any sign of worn, loose or broken parts. Check the toner sensor portion of the front harness cable to make sure it is properly seated into the toner sensor. If correct at both the sensor and engine board (J10), check the continuity of the cable. If incorrect, replace the cable. The toner sensor cable is part of the front harness and part of connector J10 on the engine board. Check the voltage at J10-11. It reads approximately +5 V dc. If incorrect, replace the engine board. If correct, check the voltage at J10-12. It reads approximately +5 V dc with the controller board removed from the printer. If incorrect, replace the engine board. If correct, replace the toner sensor assembly. A bad ground connection between J10-13 on the engine board and pin 3 on the toner sensor results in a 929 service error. 2-102 Service Manual