Canon PC940 Service Manual - Page 268

Making Pre-Checks Clean the parts. Scanning system, pickup/feeding system, delivery assembly NO Is the copy density correction switch (SW101) set to the middle index? (Note 1) Set it at the middle. YES Select non-AE, and set the copy density adjusting lever to the middle index; then, make two to three copies of the Test Sheet (NA-3). Check the following: 1. Density of gray scale No. 9 2. Presence/absence of difference between front and rear (Note 2) 3. Density of gray scale No. 1 (good or bad; Note 2) 4. Fogging of background (Note 2) I. MAINTENANCE AND INSPECTION A. Image Adjustment Basic Procedure Adjusting the Optimum Density Is gray scale No. 9 barely visible? NO YES Can the deviation be corrected using the copy density correction switch (SW101)? (Note 1) NO YES Is the optimum density obtained by intensity adjustment? (Note 3) NO YES Check the following: 1. Cartridge 2. Scanning lamp 3. AE sensor PCB 4. DC controller PCB 5. Composite power supply PCB (See the appropriate troubleshooting procedure.) END Note: 1. Applies only if the machine is equipped with a copy density correction switch (SW101). 2. The machine is not equipped with a function to correct image faults. See the appropriate troubleshooting procedure. 3. See p. 11-42. COPYRIGHT © 1999 CANON INC. CANON PC800s/900s REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON) 11-3