HP 8550 Service Manual - Page 532

E402 This error indicates that either the belt motor (M3) does not rotate or the belt motor sensor (S10) is faulty. This error occurs when the number of belt motor clock pulses per 200 ms is fewer than the specified value. Cause Step Belt motor clock 1 sensor (S10) Belt motor (M3) 2 Checks Yes/No Action Set the meter range to 20 V dc, NO and connect the + probe to J9-B4 and the - probe to J-B3 on the DADF controller PCB. Does the reading jump between 0 V and 5 V when the clock disk is turned slowly by hand? Check the wiring from the belt motor clock sensor (S10) to the DADF controller PCB. If normal, replace the belt motor clock sensor (S10). Set the meter range to 200 V dc, and connect the + probe to J7-1 and the - probe to J7-2 on the DADF controller PCB. Does the reading change to 23 V when the Copy Start key is pressed? YES NO Check the wiring from the belt motor (M3) to the DADF controller PCB. If normal, replace the belt motor (M3). Replace the DADF controller PCB. E403 This error indicates that either the ADF motor (M2) does not rotate, or the ADF motor sensor (S9) is faulty. This error occurs when the number of ADF motor clock pulses per 200 msec is fewer than the specified value. Cause Step ADF motor clock 1 sensor (S9) ADF motor (M2) 2 Checks Yes/No Action Set the meter range to 20 V dc, NO and connect the + probe to J9-A11 and the - probe to J9-A10 on the DADF controller PCB. Does the reading jump between 5 V and 0 V when the clock disk is turned slowly by hand? Check the wiring from the ADF motor clock sensor (S9) to the DADF controller PCB. If normal, replace the ADF motor clock sensor (S9). Set the meter range to 200 V dc, and connect the + probe to J11-1 and the - probe to J11-2 on the DADF controller PCB. Does the reading change to 23 V when the Copy Start key is pressed? YES NO Check the wiring from the ADF motor (M2) to the DADF controller PCB. If normal, replace the ADF motor (M3). Replace the DADF controller PCB. 530 Chapter 7 - Troubleshooting EN