Malfunction Troubleshooting - Canon LBP-800 Service Manual

CHAPTER 4
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 proce-
dure.
V-1. No AC power
<Possible causes>
1) Blown fuse (FU101)
Action: Refering to page 3-22 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: Make a check according to 5-1 "No AC power".
2) Overcurrent/overvoltage detection circuit activated
Action: If the problem is not rectified after the power switch is turned OFF and then ON
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: Refering to page 3-22 in Chapter 3, replace the fuse (FU102).
4) Defective engine controller PCB
Action: Replace the engine controller PCB.
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