HP LaserJet 4345mfp Series Service Manual - ENWW

Horizontal linesTable 7-18 Horizontal lines (perpendicular to the paper-path direction)Possible cause1 If the lines are repeated at a consistent interval downthe page, a repetitive defect exists.2 Sharp, random lines indicate a problem with the laser/scanner control circuitry.SolutionUse the repetitive defect ruler to determine the causeof this defect. See Repetitive defect ruler.1 Check the cables between the dc controller andthe laser/scanner assembly.2 If the cables are not connected, connect thecables.3 Print an engine test page. See Engine test. If thedefect appears on the engine test page, replacethe dc controller PCA. See DC controller.4 If, after checking the cables between the dccontroller and the laser/scanner, the problempersists, replace the laser/ scanner assembly.See Laser/scanner.5 If, after replacing the dc controller PCA, theproblem persists, replace the Formatterassembly. See Formatter cover and formatter.Image-formation troubleshooting 373