Zero Level Check; Method 1 - Canon iR5000 Service Handbook

CHAPTER 2 STANDARDS AND ADJUSTMENTS

8.3 Zero Level Check

A "zero level check" is a check made to find out whether the control system of the DC
controller PCB identifies 0 V when the drum surface potential is 0 V.
A zero level check may be made in either of two ways, so as to find out whether a circuit
on the the DC controller PCB or the potential measurement circuit is normal:

1) Method 1:

2) Method 2:
8.3.1 Method 1
1) Turn off the main power switch.
2) Remove the rear upper cover.
3) Short CP106 [1] and CP105 [2] on the DC controller PCB using a cable whose both
ends are equipped with an alligator clip or a probe.
When shorting CP106 and CP105, be sure to keep the shorting tool away
from other elements or the pattern on the PCB.
[2]
2-48
for checking the level shift circuit of the DC controller PCB
for checking the potential measurement circuit
J117
J116
J121
CP101
CP105
CP109
J201
CP108
J107 J112 J104
J120
J302
CP104
CP106
CP110
J115
J105
F02-803-01
J123
J114
CP103
CP111
CP107
J102
[1]