Canon NP6085 Service Manual

Contents

Canon NP6085 Service Manual Manual pdf 235 page image

COPYRIGHT © 1996 CANON INC. CANON NP6085 REV.0 JULY 1996 PRINTED IN JAPAN (IMPRIME AU JAPON)3. OPERATIONS AND TIMING3-177Adjust the volume of the primary chargingassembly if• you have replaced the drum,• you have replaced the primary chargingassembly, or• the value of VDM in service mode ( )is not VDT ±30 V.1) Connect the power plug, and wait for 10 min ormore after turning on the drum heater.2) Turn the volume of the charging assembly fullyto the left (to prevent excess increases inpotential).3) Select ‘GRID_ADJ’ in service mode ( ).4) Press the key.5) Turn the volume clockwise slowly while thephotosensitive drum rotates for 30 sec so thatthe value of DPOT is VDT ±60 V (as close toVDT as possible).6) Press the Reset key ( ).7) Turn OFF and then ON the power switch.8) Check to make sure that the value of VDM inservice mode ( ) is VDT ±30 V.Otherwise, start over with step 3).1) Install the new DC controller PCB.2) Press the service mode switch (SW921) with ahex key.3) Select ‘RAM_INIT’ in service mode ( ).4) Press the key (to initialize the RAM).5) Enter the values recorded on the label behindthe front door.6) Execute AE adjustment.7) Enter the settings prepared for the user in ser-vice mode ( ).8) Press the Reset key ( ) twice.a. OutlineWhen image faults occur, it is important to findout if the cause is in the latent image formationblock (including the photosensitive drum and thepotential control system) or in the developing/transfer mechanism.To do so in turn requires a check to make surethat the surface potential is correct. (Use servicemode to make such a check.)b. Disabling Automatic ControlYou can check if the corona current control,lamp intensity control, or developing bias controlmechanism is normal or otherwise by disablingautomatic control (non-automatic control mode).You may take advantage of non-automaticcontrol mode as an emergency remedy for a faultin any of the above automatic control mecha-nisms.In non-automatic control mode, outputs arefixed to defaults:q Steps1) Select ‘PO.CONT’ in service mode ( ).2) Check to make sure that the notation on themessage display is as follows:3) Press the OK key on the control panel.(This switches to non-automatic controlmode.)4) Press the Reset key ( ) on the con-trol panel twice.Initiating non-automatic control mode fix alloutputs of corona current control, intensitycontrol, and developing bias control to theirrespective default values.[4[[5[OK[4[[1[OK[4[[1[7 Adjusting the Volume of thePrimary Charging Assembly8 After Replacing the DC ControllerPCB9 Checking the Surface PotentialControl SystemPO.CONT : 0 (0 : ON 1 : OFF)Note: