CHAPTER 10 TROUBLESHOOTINGCOPYRIGHT © 1999 CANON INC. CANON NP6317 REV.0 APR. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON) 10-3520. Unsharp (Unforcussed) imageAction1.Check if thecopyboard copy iswrapped.2.Explain to the userhow to place the origi-nal on the copyboard.Clean the copyboardglass.Check the lens driveunit.Adjust the distance be-tween the No.1 mirrormount and the mirror 2mount.Clean the scanning lamp,reflectors, mirrors, lens,and dust-proofing glass.ResultNoYesNoNoYesCheckIs the original lying flat on the glass?Is any oil or other substance adhering tothe copyboard glass?Set the power switch OFF and then ONagain. Does the lens move smoothly?Is the horizontal reproduction ratio withinthe standard for a DIRECT copy?Procedure1234Cause/ProblemareaOriginalCopyboardglassLens driveassemblyMirrorpositionDirt on thescanner21. Blank imageActionInsert the drum unit.Insert the developing as-sembly.1.Check if the photosen-sitive drum rotatessmoothly.2.Check the drum driveunit.Replace the DC control-ler PCB.Replace the high-voltagetransformer (HVT).ResultNoNoNoNoYesCheckIs the drum unit inserted?Is the developing assembly inserted?Does the photosensitive drum rotate dur-ing copying?Set the meter to the 30VDC range andmeasure the voltage between J307-1 (+)(GRDON) and J307-7 (-) of the DC con-troller PCB. Is the voltage approx. 15Vwhen the scanner is advancing and 0V atother times?Procedure1234Cause/ProblemareaDrum unitDevelopingassemblyDrum driveunitDC controllerPCBHigh-voltagetransformer(HVT)
