COPYRIGHT © 2000 CANON INC. 2000 2000 2000 2000 CANON iR5000/iR6000 REV.0 JULY 2000CHAPTER 3 STANDARDS AND ADJUSTMENTS3-29 T8. Checking the Surface Potential Control System8.1 OutlineIn the event of an image fault, it is important to find out if the cause is within the staticlatent image formation block (including the photosensitive drum and the potential controlsystem) or is with the developing/transfer mechanism; and to isolate the cause, the surfacepotential must first be checked in service mode.8.2 Disabling the Auto Control MechanismThe potential control system may be checked by disabling the auto control mechanism(referred to hereafter as “non-auto control mode).If improvements are noted in the images made in non-auto control mode, the potentialmeasurement unit and the DC controller PCB may be suspected.Further, non-auto control mode may also be made use of as an emergency measureagainst an error in the auto control mechanism.In non-auto control mode, all control settings (corona current, intensity, de-veloping bias) will automatically be set to the standard settings stored in theROM.Starting Non-Auto Control Mode1) Make the following selections in service mode, and enter ‘0’:COPIER>OPTION>BODY>PO-CNT; then, press the OK key.2) Press the Reset key twice.
