User Guide

Removal and replacement strategy.....................................................................................................168
Required tools.....................................................................................................................168
Before performing service ..................................................................................................169
After completing service ....................................................................................................169
Screws used in the printer .................................................................................................170
Parts-removal tree .............................................................................................................171
Printer input tray, and cabinet wheel locks.........................................................................172
Dc controller PCA diagram.................................................................................................173
User-replaceable parts ......................................................................................................................175
Print cartridge .....................................................................................................................175
Transfer roller ....................................................................................................................177
Fuser...................................................................................................................................178
Tray 1 pickup roller ............................................................................................................179
Tray 1 separation pad.........................................................................................................181
Tray 2 feed rollers...............................................................................................................182
Covers, tray 1, and the rear output bin................................................................................................186
Accessory covers and the tray 2 extension door ...............................................................187
Formatter cover...................................................................................................................191
Top cover............................................................................................................................192
Right-side cover .................................................................................................................195
Left-side cover....................................................................................................................197
Front cover..........................................................................................................................198
Tray 1..................................................................................................................................200
Rear output bin...................................................................................................................203
Control-panel display...........................................................................................................................204
Control-panel overlay .........................................................................................................204
Control-panel assembly .....................................................................................................205
Main assemblies .................................................................................................................................209
Firmware DIMM (LJ 4200/4300 only).................................................................................210
Formatter assembly ...........................................................................................................211
Reinstallation notes, formatter ...........................................................................................212
Installing a new formatter and a new dc controller (LJ 4250/4350 only)............................213
Output-delivery assembly ..................................................................................................214
Duplexing-pendulum assembly...........................................................................................217
Laser/scanner assembly.....................................................................................................219
Paper-pickup drive assembly .............................................................................................222
Tray 2 lifter-drive assembly.................................................................................................227
Dc controller PCA...............................................................................................................230
Reinstallation tip..................................................................................................................235
Installing a new formatter and a new dc controller (LJ 4250/4350 only)............................235
Power supply......................................................................................................................236
Paper-feed belt assembly...................................................................................................243
Motors and fans...................................................................................................................................245
Main cooling fan (left side) .................................................................................................246
Cooling fan, right side (HP LaserJet 4250/4300/4350 Series printers only) .....................248
Removing the fan without removing the air duct................................................248
Removing the fan and the air duct together.......................................................251
Print-cartridge motor (HP LaserJet 4250/4300/4350 series printer only)...........................253
Main motor .........................................................................................................................255
Pickup and feed assemblies ...............................................................................................................257
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