F. Electrical System1. When Replacing the DC Controller PCB1) Install a new DC controller PCB.2) Press the service mode switch over the cover with a clip.3) Select RAM_INIT:0 ← (]: START) in service mode ( ).4) Press the ] user mode key.5) Execute AE adjustment.6) Enter the values recorded on the label attached behind the front door.7) Enter the appropriate settings for the user in service mode ( ).8) Press the Reset key twice.2. Checking the Surface Potential Control Systema. OutlineIf image faults are noted, you must first find out whether the problem is in the latentimage formation block including the photosensitive drum and the potential controlsystem or it is in the developing/transfer mechanism.To do so, it is important to check to see whether the surface potential is optimum.You can check the surface potential in service mode.b. Disabling the Auto Control MechanismYou may disable the auto control mechanism as a way to find out whether the coronacurrent control, lamp intensity control, or developing bias control mechanism is faulty(non-auto control mode).You may also use non-auto control mode as a tentative remedy for a fault in the autocontrol mechanism. In non-auto control mode, all outputs are fixed to their appropriatevalues.q Steps1) Select ‘PO_CONT’ in service mode ( ).2) Check to make sure that the indication on the message display is as follows:NIP : 0 ← (] : START)PO_CONT : 0 ← (] : START)Changes to ‘1’.3) Press the ] user mode key. (non-auto control mode selected)NIP : 0 ← (] : START)PO_CONT : 1 ← (] : START)4) Press the Reset key twice.]4]]5]]4]COPYRIGHT © 1997 CANON INC. CANON NP6045 REV. 1 MAR. 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)CHAPTER 10 TROUBLESHOOTING10-35
