HP LaserJet 3052 Service Manual - Page 120

Removal and replacement strategy, Electrostatic discharge

Page 120 highlights

Removal and replacement strategy This chapter documents the removal and replacement of field-replaceable parts (FRUs) only. Reinstallation is generally the reverse of removal. Occasionally, notes and hints are included to provide directions for difficult or critical replacement procedures. HP does not support the repairing individual subassemblies or troubleshooting at the component level. Note the length, diameter, color, type, and location of each screw. 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 become 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. WARNING! Unplug the power cord from the power outlet (at the wall receptacle) before attempting to service the all-in-one. It this warning is not followed, severe injury can result. Certain functional checks during troubleshooting must be performed with power supplied to the all-inone. However, the power supply should be disconnected during removal. Sheet-metal and plastic edges in the all-in-one can be sharp. Use caution when servicing this all-in-one. Never operate or service the all-in-one with the protective cover removed from the laser/scanner assembly. The invisible reflected beam can damage your eyes. CAUTION Do not bend or fold the FFCs during the removal or reinstallation process. Also, do not straighten pre-folds in the FFCs. You must make sure that all FFCs are fully seated in their connectors. Failure to fully seat an FFC into a connector can cause a short circuit in a PCA. NOTE For service purposes, the upper part of the all-in-one is, in effect, the "scanner" and the base part is the "printer." Together, they also act as a photocopier (all models of the HP LaserJet 3050/3052/3055 all-in-one) or fax machine (HP LaserJet 3050 all-in-one and HP LaserJet 3055 all-in-one), but the service description here is simplified by referring to copier or fax functionality only when specifically necessary. Hint 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. Electrostatic discharge CAUTION The all-in-one contains components that are sensitive to electrostatic discharge (ESD). Always perform service work an ESD-protected workstation. If an ESD- protected workstation is not available, discharge body static by grasping the print engine chassis before touching an ESD-sensitive component. Ground the print engine chassis before servicing the all-in-one. 100 Chapter 5 Removal and replacement ENWW

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Removal and replacement strategy
This chapter documents the removal and replacement of field-replaceable parts (FRUs) only.
Reinstallation is generally the reverse of removal. Occasionally, notes and hints are included to provide
directions for difficult or critical replacement procedures.
HP does not support the repairing individual subassemblies or troubleshooting at the component level.
Note the length, diameter, color, type, and location of each screw. 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 become
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.
WARNING!
Unplug the power cord from the power outlet (at the wall receptacle) before
attempting to service the all-in-one. It this warning is not followed, severe injury can result. Certain
functional checks during troubleshooting must be performed with power supplied to the all-in-
one. However, the power supply should be disconnected during removal.
Sheet-metal and plastic edges in the all-in-one can be sharp. Use caution when servicing this
all-in-one.
Never operate or service the all-in-one with the protective cover removed from the laser/scanner
assembly. The invisible reflected beam can damage your eyes.
CAUTION
Do not bend or fold the FFCs during the removal or reinstallation process. Also, do
not straighten pre-folds in the FFCs. You
must
make sure that all FFCs are fully seated in their
connectors. Failure to fully seat an FFC into a connector can cause a short circuit in a PCA.
NOTE
For service purposes, the upper part of the all-in-one is, in effect, the "scanner" and the
base part is the "printer." Together, they also act as a photocopier (all models of the HP LaserJet
3050/3052/3055 all-in-one) or fax machine (HP LaserJet 3050 all-in-one and HP LaserJet 3055
all-in-one), but the service description here is simplified by referring to copier or fax functionality
only when specifically necessary.
Hint
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.
Electrostatic discharge
CAUTION
The all-in-one contains components that are sensitive to electrostatic
discharge (ESD). Always perform service work an ESD-protected workstation. If an ESD-
protected workstation is not available, discharge body static by grasping the print engine chassis
before touching an ESD-sensitive component. Ground the print engine chassis
before
servicing
the all-in-one.
100
Chapter 5
Removal and replacement
ENWW