Malfunction Status Troubleshooting - Canon LBP-1000 Service Manual

VI. MALFUNCTION STATUS TROUBLESHOOTING
If the factor of the malfunction is identified as "malfunction status troubleshooting" by the mal-
function diagnosis flowchart (Figure 4-1-1), execute the followings and mend the malfunction.
VI-1. "5F-50 ERROR" (Fixing unit failure)
<Possible causes>
1. Shorted / broken thermistor
Action: Turn the power OFF and remove the fixing unit from the printer. Measure the resis-
tance between the fixing unit connector J301-1 (FSRTH) and J301-2 (GND). If the
resistance is approximately from 350k
20°C), replace the fixing film unit.
2. Broken heater wire / blown thermal fuse
Action: If there is no continuity between the fixing unit connector J 303-1(ACH) and J303-
2 (ACN) with the fixing unit removed from the printer, replace the fixing film unit.
3. Defective engine controller PCB
Action: Replace the engine controller PCB.
VI-2. "5F-51 ERROR" (BD failure)
"5F-52 ERROR" (Scanner unit failure)
<Possible causes>
1. Poor contact in laser/scanner unit connectors
Action: Reconnect the BD PCB connector J1706, laser driver PCB connector J801, and
scanner motor connector J1705.
2. Poor contact in intermediate PCB connectors
Action: Reconnect the intermediate PCB connectors J1009 and J1001.
3. Defective laser/scanner unit
Action: Replace the laser/scanner unit.
4. Defective intermediate PCB
Action: Replace the intermediate PCB.
5. Poor contact in engine controller PCB connector
Action: Reconnect the engine controller PCB connector J401 correctly.
6. Defective engine controller PCB
Action: Replace the engine controller PCB.
VI-3. "5F-59 ERROR" (Cooling fan failure)
<Possible causes>
1. Poor contact in fan drive signal line connector
Action: Reconnect the intermediate PCB connector J1005 correctly.
2. Defective fan motor
Action: Disconnect the intermediate PCB connector J1005. Measure the voltage between
to 520k (at the room temperatures of
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