HP LaserJet 9000 Service Manual - Page 115

Introduction Removal and replacement strategy This chapter documents removal and replacement of field replaceable units (FRUs) only. Replace parts in the reverse order of their removal. Directions for difficult or critical replacement procedures are included. Repair notices WARNING! The printer can have sharp sheet metal edges. Use caution when working on the printer. CAUTION Always remove the print cartridge before removing or replacing assemblies and parts (see page 119). IMPORTANT: Put the print cartridge in its original print-cartridge bag, or, if the bag is not available, cover the print cartridge with a piece of paper. Light can damage the print cartridge. To install a self-tapping screw, first turn it counterclockwise to align it with the existing thread pattern, then carefully turn it clockwise to tighten. Do not overtighten the screw. If a self-tapping screw-hole becomes stripped, repair the screw-hole or replace the affected assembly. Note Note the lengths, diameters, and locations of screws. Be sure to return each screw to its original location during reassembly. Incorrectly routed or loose wire harnesses can interfere with other internal components and can be damaged or broken. Frayed or pinched harness wires can be difficult to locate. When replacing wire harnesses, always use the provided wire loops, lance points, or wire-harness guides. Electrostatic discharge (ESD) CAUTION The printer contains parts that are sensitive to electrostatic discharge (ESD). Always service the printer at an ESD-protected workstation, or use an ESD mat. CAUTION Watch for the ESD symbol (shown at left) to identify the parts that are sensitive to ESD. Protect these parts by using an ESD wrist strap and protective ESD pouches. Required tools The following tools are needed to service the printer: z #2 Phillips screwdriver with magnetic tip z T-10 TORX screwdriver z T-20 TORX screwdriver z Small, flatblade screwdriver z Small needle-nose pliers z ESD mat z Penlight A pozidrive screwdriver will damage screw-heads on the printer. Use a #2 Phillips screwdriver. If you have a multi-speed screwdriver, use a torque limiter. Introduction 99