3. Checking the Potential SystemCOPYRIGHT © 1997 CANON INC. CANON NP6560/NP6360/NP6260 REV. 0 NOV. 1997 PRINTED IN JAPAN (IMPRIME AU JAPON) 11-45Short J127-1 and -2 on the DCcontroller PCB with a jumper wire.Disconnect J103.Select non-potential mode. ( * 4 * ;'PO.CONT' '1')Turn off the power switch.Remove the jumper wire used toshort J127-1 and -2 on the DCcontroller PCB. Connect J103.Check to make sure that power ison the potential measurement PCB,and replace the potentialmeasurement unit.Turn off the power switch.Turn on the power switch.Select non-potential control mode.( * 4 * .CONT' '1')Measure the voltage during copyingbetween J114-A6 (+) and -A13 (-)on the DC controller PCB. (step A)Check the transfer chargingassembly for leakage. Try changingthe setting of 'FUZZY' in servicemode ( * 5 * ). Try replacing copypaper.Replace the DC controller PCB.Select the activation voltage limiterof the scanning lamp( * 1 * ; 'LIMT').Select potential control mode.( * 4 * ; 'PO.CONT' '0')Turn on the power switch.Clean the standard white plate,mirror, lens, and dust-proofingglass; then, turn off and on thepower switch.Select non-potential control.( * 4 * ; 'PO.CONT' '1')STARTNOYESNOYESNOYESNOYESNOYESNO(transfer output)(zero-level check)End.Turn on the power switch.Start servicemode ( * 4 * ). Is the indicationof address P023 during initialrotation between'0003' and'001B'? Is theactual measurement ofstep A and the reading of 'TC' inservice mode ±10%?NO Has the image improved?Is thetoner image on thephotosensitive drum beforetransfer normal?AReplace thehigh-voltage transformer.Is the problem corrected?Is 'LIMT' '1'?Is 'LIMT' '1'?YESYESMeasure the voltage during copyingbetween J111-B7 (+) and -B8 (-) onthe DC controller PCB.BStart service mode ( * 1 * ), andselect 'TC' (transfer chargingassembly current). Convert thereading (unit: μA) into its controlvoltage as shown in 4 "PotentialControl Conversion Table."Replace the DC controller PCB.
