Canon iR6570 Series Portable Manual page 47

When the machine is in non-auto control mode, all settings used for corona current control, laser power control, and
developing bias control will be automatically be set to default settings.
Using Non-Auto Control Mode
1)Make the following selections in service mode, enter '0', and press the OK key:
COPIER>OPTION>BODY>PO-CONT.
2) Press the Reset key twice.
3. Making a Zero-Level check
A "zero-level check" is a check made to see if the control mechanism of the DC controller PCB is identifying a
0-V level without fail when the drum surface potential is 0 V.
A zero-level check may be made in either of 2 ways, and you can use it to decided whether the DC controller
PCB and the potential measurement PCB is free of error:
Method 1: use it to find out if the level shift circuit on the DC controller PCB is free of a fault
Method 2: use it to find out if the potential control circuit is free of a fault
(1) Method 1
1) Turn off the main power switch.
2) Remove the upper rear over.
3) Short GP33 on the DC controller PCB and GND using a cable equipped with an alligator clips or probes on both
ends.
When shorting CP33 and GND, take full care to avoid contact between the clip/probe and the pattern of the PCB and
other elements.
4) Remove the left cover (upper), delivery cover, and left cover (middle).
5) Remove the 5 screws [1], and detach the PCB cover [2].
6) Disconnect the connector [1] connected to the DC controller PCB of the potential control PCB.
[1]
[1]
[1] [2]
F-2-13
[1]
Chapter 2
2-13