Canon PC940 Service Manual - Page 321

CHAPTER 11 TROUBLESHOOTING 12 The copy has white spots. (horizontal) Cause Copy paper Step Checks 1 Is the paper of a recommended type? 2 Try paper fresh out of package. Is the problem corrected? Scanner rail 3 Is the problem noted at the same position on all copies? Scanning lamp, Developing bias YES/NO YES YES Yes NO Action Try a recommend type. If the results are good, ask the user to use a recommended type. The paper may be moist. Instruct the user on the correct method of storing paper. 1. Check the scanner rail for foreign matter. 2. Adjust the tension of the scanner cable. Check the scanning lamp for flickering and the presence/ absence of a developing bias. 13 The back of the copy is soiled. Cause Transfer guide assembly Feeding assembly Pickup guide assembly, Delivery roller Step 1 2 3 Checks Turn off the power while copy paper is moving through the feeding assembly. Is the back of the paper soiled? Is the transfer guide assembly soiled? Is the feeding assembly soiled? YES/NO NO YES YES NO Action Go to step 3. 1. Clean the transfer guide. 2. Clean the registration roller. 3. Check the varistor. 4. Check the cartridge for leakage of toner. Clean the feeding assembly. Clean the pickup guide assembly and the delivery roller. 11-56 COPYRIGHT © 1999 CANON INC. CANON PC800s/900s REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)