Canon CLBP-460PS, Service Manual, Page: 272 / 566

5) Deformed/deteriorated secondary transfer roller
Action: Replace the secondary transfer roller.
6) Poor contact in connectors
Action: Reconnect the connectors between the DC controller PCB and the high-voltage PCB.
7) Defective high-voltage PCB (insufficient output of primary or secondary transfer bias)
Action: Replace the high-voltage unit.
8) Defective DC controller PCB
Action: Replace the DC controller PCB.
9) Defective high-voltage PCB (insufficient developing bias output)
Action: Replace the high-voltage unit.
10) Defective laser/scanner unit PCB
Action: Replace the laser scanner unit PCB.
11) Defective DC controller PCB
Action: Replace the DC controller PCB.
[ 2-2 ] Dark
<Possible causes>
1) The image density is not adjusted correctly.
Action: Adjust the image density by operating the external device.
2) Dirty density sensor unit
Action: Clean the lens in the density sensor unit with blush.
3) Poor contact in connectors
Action: Check the wiring between the primary charging contact, high-voltage PCB, and DC
controller PCB and reconnect the connectors correctly.
4) Defective high-voltage PCB (primary charging bias output shortage)
Action: Replace the high-voltage unit.
5) Defective DC controller PCB
Action: Replace the DC controller PCB.
[ 2-3 ] Completely blank
<Possible causes>
1) The claw for open/close laser shutter in the drum cartridge is damaged
Action: Replace the drum cartridge.
2) Malfunctioning or damaged shutter arm and laser shutter
Action: Replace the parts if they do not move smoothly.
3) Poor contact in the rotary drive unit developing bias contact
Action: Clean the developing bias contact of the rotary drive unit.
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CHAPTER 4