Canon LBP1760P, Service Manual

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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.
M-1. "5F-50 ERROR" (fixing unit malfunction)
<Possible causes>
1. Broken or short-circuited thermistor
Action: Turn the power OFF and remove the fixing unit. Measure the resistance between
the fixing unit connector J132-1 (THRM) and J132-2 (GND). If the resistance is not
in the range of 300k to 500k (standard temperature), replace the fixing film unit.
2. Broken heater wire/blown thermal fues
Action: If there is no continuity between the fixing unit connectors J143F (NEUTRAL) and
J142F (HOT) with the fixing unit removed, replace the fixing film unit.
3. Defective engine controller PCB
Action: Replace the engine controller PCB.
M-2. "5F-52 ERROR" (Scanner unit malfunction)
<Possible causes>
1. Poor contact in laser/scanner unit connectors
Action: Reconnect the BD PCB connector J551, laser driver PCB connector J501 and scan-
ner motor connector J401.
2. Poor contact in engine controller PCB connector
Action: Reconnect the engine controller PCB connector J53 correctly.
3. Defective laser/scanner unit
Action: Replace the laser/scanner unit.
4. Defective engine controller PCB
Action: Replace the engine controller PCB.
M-3. "5F-54 ERROR" (Main motor malfunction)
<Possible causes>
1. Poor contact in the MAIN MOTOR DRIVE signal line connectors
Action: Reconnect the main motor connector J301 and engine controller PCB connector J52
correctly.
2. Defective main motor
Action: Replace the main motor.
3. Defective engine controller PCB
Action: Replace the engine controller PCB.
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CHAPTER 4