Lexmark Optra C710 Service Manual - Page 110

5016-001 C 991 Service - Engine error. Note: This error displays when a problem exists with the coupling on and off sensors. The same error displays for either sensor. FRU 1 Coupling On/Off Sensors Engine Board SN Cable Engine Board 2 Coupling Cam Action Turn the printer on and observe how long it takes for the error to display. If the coupling On sensor is failing, the warm-up will be shorter than the coupling Off sensor. Check the sensors by manually positioning the coupling cam disk over the coupling on (upper) sensor while turning the printer on. If the disk moves out of coupling, and the error displays, there is a problem with the coupling On sensor. If you manually position the coupling cam disk over the coupling Off (lower) sensor, while turning the printer on and the disk moves out of the Off sensor and then moves back into the sensor, there is a problem with the Off sensor. Coupling On sensor Pin # 1 2 3 Signal Voltage +5 V dc CUPON DGND Voltage Cam Disk in +5 V dc +5 V dc 0 V dc Voltage Cam Disk Out +5 V dc 0 V dc 0 V dc Coupling Off sensor Pin # 1 2 3 Signal Voltage +5 V dc CUPOFF DGND Voltage Cam Disk in +5 V dc +5 V dc 0 V dc Voltage Cam Disk Out +5 V dc 0 V dc 0 V dc If a problem cannot be isolated with the sensors, check the SN cable. • If incorrect, replace the cable. • If correct, replace the engine board. Check the coupling cam and associated parts for correct operation. If a problem is found, repair or replace the motor mounting stay A assembly. 2-44 Service Manual