Malfunction Troubleshooting - Canon LBP-1760 Service Manual

CHAPTER 4
V. MALFUNCTION TROUBLESHOOTING
If the factor of the malfunction is identified as "malfunction troubleshooting" by the malfunction
diagnosis flowchart (Figure 4-1-1), execute the followings and mend the malfunction.
E-1. No AC power
<Possible causes>
1. Blown fuse (FU1)
Action: Replace the fuse (FU1) on the engine controller PCB.
2. Defective engine controller PCB
Action: Replace the engine controller PCB.
E-2. No DC power
<Possible causes>
1. No AC power is supplied.
Action: Check the AC power supply according to "E-1. No AC power."
2. The overcurrent/overvoltage detection circuit activated
Action: If the problem is not rectified after the power switch is turned OFF and ON again,
find the cause of activation of the overcurrent/overvoltage detection circuit in the
engine controller PCB. Wait for two minutes or more before turning the power back
ON.
3. Blown fuse (FU2)
Action: Replace the fuse (FU2) on the engine controller PCB.
4. Defective wiring, DC load and engine controller PCB
Action: Turn the power OFF. Check the wiring ahead of the engine controller PCB and the
DC loads. If problem is found, replace the relevant part. If no problem is found
with the wiring and DC loads, replace the engine controller PCB.
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