HP 8550 Service Manual - Page 496

Connector 7 Power supply 8 (printer unit) Are connector J222 on the dc NO controller PCB and connector J26 of the fusing assembly connected securely? Replace the power supply of the printer unit. Is the problem corrected? YES NO Connect the connectors securely. End. Replace the dc controller PCB. CAUTION If E001 or E003 is indicated, be sure to discharge the error memory capacitor (C259) on the dc controller PCB after troubleshooting the problem, as it may contain error memory. (Short out JP201 on the dc controller PCB to discharge C259; see the Printer Unit Service Manual.) E001 (printer) The fusing assembly has overheated. This error occurs when the fusing temperature during standby or copying exceeds 230° C. Cause Step Upper 1 thermistor (short circuit) Lower 2 thermistor (short circuit) Checks Y/N With the fusing assembly removed, measure the resistance between connectors J26F-A4 (FXTHU) and J26F-A3 (GND) on the fusing assembly side. Is it 2 KΩ or less? YES Measure the resistance between YES connectors J26F-A2 (FXTHL) and J26F-A1 (GND) on the fusing assembly side. Is it 2KΩ or less? Power supply 3 (printer unit) Replace the power supply of the printer unit. Is the problem corrected? YES NO Action Check the wiring from connector J222 on the dc controller PCB to the upper thermistor; if normal, replace the fuser assembly. Check the wiring from connector J222 on the dc controller PCB to the lower thermistor: if normal, replace the fuser assembly. End. Replace the dc controller PCB. CAUTION If E001 or E003 is indicated, be sure to discharge the error memory capacitor (C259) on the dc controller PCB after troubleshooting the problem, as it may contain error memory. (Short out JP201 on the dc controller PCB to discharge C259; see the Printer Unit Service Manual.) 494 Chapter 7 - Troubleshooting EN