HP 8550 Service Manual - Page 517

E807 (printer) The heat discharge fan (FM3, used for the area around the scanner) is faulty. This error occurs when the fan motor lock signal (FAN3LK) goes to one (1) for 1.5 seconds or more while the fan is rotating. Cause Connectors (heat discharge fan 3 drive assembly) Step 1 Connectors (24 2 V for heat discharge fan 3 drive) Heat discharge 3 fan 2 Main relay PCB 4 The dc power 5 (printer unit) Checks Y/N Are connectors J681 and J682 on NO the pre-exposure LED relay PCB and relay connectors J18 and J17, connectors J645 and J647 on the main relay. PCB, and connector J227 on the dc controller PCB connected securely? Are connectors J641 on the main NO relay PCB and J102 on the dc power supply connected securely? Does the voltage change to about YES 24 V between connectors J645-3 (FAN3ON) on the main relay PCB and J645-1(GND) immediately after the copier is turned on? Does the voltage change to 24V between connectors J641-1 (+24 VB) and J641-4 (GND) on the main relay PCB immediately after the copier is turned on? YES Is the dc power present in the NO printer unit? YES Action Connect the connectors securely. Connect the connectors securely. Replace the heat discharge fan 3. Replace the main relay PCB. See "No dc power in the printer (+5V, +24 VB)" on page 522. Replace the dc controller PCB. E808 (printer) The fusing drive circuit power unit is faulty. This error occurs when the fusing heater safety circuit has detected a fault in the upper and lower fusing heaters. Cause Fusing assembly Power supply (printer unit) Step 1 2 Checks Replace the fusing assembly. Is the problem corrected? Replace the power supply on the printer side. Is the problem corrected? (The fusing heater drive circuit or the fusing heater safety circuit is faulty.) Y/N YES YES NO Action End. End. Replace the dc controller PCB. EN Copy module troubleshooting 515