COPYRIGHT © 1999 CANON INC. CANON 660/2100 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)CHAPTER 10 TROUBLESHOOTING10-151 The print is too light.CauseBlack tonercartridgeHigh-voltagePCB 1 (inade-quate blackdeveloping biasoutput)Secondary pre-transfer charg-ing assemblyIntermediatetransfer drumunitHigh-voltagePCB 2 (inade-quate pre-transfer charg-ing bias output)Step123456Yes/NoYESYESNOYESYESNOYESActionIf the problem is blackonly, go to step 2.If the problem is threecolors, go to step 7.If the problem is all fourcolors, go to step 9.If the problem is onecolor, go to step 7.Clean the contact. If itis deformed, replacethe problem part. Also,check for a displacedcontact.Replace the high-volt-age PCB 1.Replace the secondarypre-transfer chargingassembly.Clean the contact. If itis soiled or damaged,replace the problempart. Also, check for adisplaced contact.Replace the DC con-troller PCB.End.ChecksMake a test print in service mode(TEST>PG>TYPE=14), and find thecolor that is light on the print.Is the color on the test print?Is the contact of the black toner car-tridge (for black developing bias) orthe contact for black developing biasof the printer unit soiled?Open the front cover while blacktoner is being developed on thephotosensitive drum (about 30 secafter the start of test printing), andtake out the black toner cartridge.Then, take out the black toner car-tridge, and check the toner imageon the photosensitive drum. Is theblack toner image fully developed onthe surface of the photosensitivedrum?Is the charging wire of the sec-ondary pre-transfer charging assem-bly inside the intermediate transferdrum unit broken?Is the contact of the intermediatetransfer drum unit (for secondarypre-transfer charging bias) or thecontact for the secondary pre-trans-fer charging bias of the printer unitsoiled?Replace the high-voltage PCB. Isthe problem corrected?Download free service manual at http://printer1.blogspot.com
