Printed circuit assemblies (PCAs)......................................................................................................131 Low-voltage power-supply PCA.........................................................................................131 DC controller PCA.............................................................................................................135 High-voltage power supply................................................................................................137 Memory-controller PCA.....................................................................................................139 Driver PCA.........................................................................................................................141 Control panel.....................................................................................................................143 Pickup-and-feed driver PCA..............................................................................................145 Duplex-driver PCA.............................................................................................................147 Sensors..............................................................................................................................................149 Cassette media sensor (HP LaserJet 3600/3800).............................................................149 Temperature sensor..........................................................................................................151 Paper and registration sensor covers................................................................................152 Cartridge-sensor PCA........................................................................................................153 500-sheet feeder................................................................................................................................156 500-sheet feeder right cover..............................................................................................156 500-sheet feeder left cover................................................................................................158 500-sheet feeder rear cover..............................................................................................161 500-sheet feeder driver PCA.............................................................................................163 Media sensor (500-sheet feeder).......................................................................................165 6 Troubleshooting Troubleshooting process....................................................................................................................170 Pre-troubleshooting checklist ............................................................................................170 Troubleshooting flowchart..................................................................................................172 Power-on checks...............................................................................................................172 Control-panel messages....................................................................................................................174 Jams...................................................................................................................................................195 Jam recovery.....................................................................................................................195 Avoiding jams....................................................................................................................196 Clearing jams.....................................................................................................................197 Image-formation troubleshooting.......................................................................................207 Print-quality problems associated with media...................................................207 Defects on overhead transparencies.................................................................................208 Print-quality problems that are related to the environment................................................208 Print-quality problems that are related to jams..................................................................209 Print-quality problems from toner buildup..........................................................................209 Print-quality troubleshooting pages...................................................................................209 Image defects.....................................................................................................................................210 Light image........................................................................................................................211 Light color..........................................................................................................................211 Dark image........................................................................................................................212 Dark color..........................................................................................................................212 Completely blank image....................................................................................................213 All black or solid color........................................................................................................213 Dots in vertical lines...........................................................................................................213 Dirt on back of paper.........................................................................................................213 Dirt on front of paper..........................................................................................................214 Vertical lines .....................................................................................................................214 White vertical lines.............................................................................................................214 vi ENWW