3–127OPERATIONS AND TIMINGCOPYRIGHT © 1998 CANON INC. CANON NP6621 REV.0 FEB. 1998 PRINTED IN JAPAN (IMPRIME AU JAPON)VIII. STANDARDS ANDADJUSTMENTSA. Electrical1 Adjustment after ReplacingPCBsYou must perform the following adjustmentswhenever you have replaced the following PCBs:a. DC Controller PCB1) Start service mode (adjustment mode [3]), andenter the settings indicated on the ServiceMode label attached behind the front door.2) Perform the multifeeder paper width sensoradjustment.3) Perform scanning lamp intensity adjustment.4) Perform AE adjustment.As necessary, change the settings of servicemode and user mode.Caution:If you changed any of the settings indicated inthe Service Mode label, be sure to record thenew settings on the label.b. Composite Power Supply PCB1) Select service mode No. 315 through No. 318(adjustment mode [3]), and enter the settingsindicated on the label attached to the compositepower supply PCB.Be sure to record any new settings in the Ser-vice Mode label.c. AE Sensor PCB1) Perform AE adjustment.Caution:If you changed any of the settings indicated inthe Service Mode label, be sure to record thenew settings on the label.d. Light Adjustment Sensor PCB1) Perform scanning lamp intensity adjustment.2) Perform AE adjustment.Caution:If you changed any of the settings indicated inthe Service Mode label, be sure to record thenew settings on the label.2 Adjusting the Scanning LampIntensitySelect service mode No. 407.1) Place the Test Sheet NA3 on the copyboard,and close the copyboard cover.2) Turn OFF AE, and make copies in continuousmode at copy density 5 and VR850 (DC bias) atcenter.3) Press the zoom + keys or zoom - key so that theoptimum image is obtained.• If the image is too light, press the zoom + key.• If the image is too dark, press the zoom - key.Reference:1. What is referred to as optimum image is animage in which gray scale No. 8 on the copycorresponds to gray scale No. 4 throughNo. 7 on the Test sheet while the copy isfree of fogging.2. Turning the VR excessively can cause E220to be displayed. If this is the case, turn theVR 301 to the center position, turn OFF/ONthe power, and make adjustments onceagain.Caution:After making the adjustment, be sure to performAE adjustment.3 AE AdjustmentPerform AE adjustment using the following threeservice modes:q AE Basic AdjustmentNo. 410 scanner forward stopNo. 408 scanning lamp ON checkNo. 208 AE sensor voltage displayNo. 301 AE scan lamp intensity automatic ad-justmentw No. 302 AE mode copy density (developingbias) reference adjustmente No. 303 AE mode copy density (developingbias) slope adjustmentIf the copy density is not optimum after perform-ing AE basic adjustment q No. 410, No. 408, No.208, and No. 301, try w No. 302 and e No. 303 insequence.
