Malfunction Troubleshooting; Troubleshooting - Canon LBP-1120 Service Manual

V. MALFUNCTION TROUBLESHOOTING
Perform troubleshooting according to the malfunction diagnosis flowchart (Figure 4-1-1). If an "malfunction" is
found, the defective part must be located and rectified by the following procedures.
V-1. No AC Power
<Possible Causes>
1. Blown fuse (FU101).
Action: Referring to VII-C-a in Chapter 3, replace the fuse (FU101).
2. Defective engine controller PCB.
Action: Replace the engine controller PCB.
V-2. No DC Power
<Possible Causes>
1. No AC power is supplied.
Action: Perform the "No AC Power" checks.
2. Overcurrent/overvoltage detection circuit is activated.
Action: If the problem persists after the power supply connector is plugged OFF and then IN again, find
the cause of activation of the overcurrent/overvoltage detection circuit in the power supply unit.
Wait for two minutes or more before turning the power back ON.
3. Blown fuse (FU102).
Action: Referring to VII-C-a in Chapter 3, replace the fuse (FU102).
4. Defective engine controller PCB.
Action: Replace the engine controller PCB.
CHAPTER 4
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