Lenovo 195143U, Hardware Maintenance Manual

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Important
Use only approved tools and test equipment. Some hand tools have handles
covered with a soft material that does not insulate you when working with
live electrical currents.
Many customers have, near their equipment, rubber floor mats that contain
small conductive fibers to decrease electrostatic discharges. Do not use this
type of mat to protect yourself from electrical shock.
v
Find the room emergency power-off (EPO) switch, disconnecting switch, or
electrical outlet. If an electrical accident occurs, you can then operate the switch
or unplug the power cord quickly.
v
Do not work alone under hazardous conditions or near equipment that has
hazardous voltages.
v Disconnect all power before:
– Performing a mechanical inspection
– Working near power supplies
– Removing or installing Field Replaceable Units (FRUs)
v
Before you start to work on the machine, unplug the power cord. If you cannot
unplug it, ask the customer to power-off the wall box that supplies power to the
machine, and to lock the wall box in the off position.
v
If you need to work on a machine that has exposed electrical circuits, observe the
following precautions:
– Ensure that another person, familiar with the power-off controls, is near you.
Attention: Another person must be there to switch off the power, if
necessary.
– Use only one hand when working with powered-on electrical equipment;
keep the other hand in your pocket or behind your back.
Attention: An electrical shock can occur only when there is a complete
circuit. By observing the above rule, you may prevent a current from passing
through your body.
– When using testers, set the controls correctly and use the approved probe
leads and accessories for that tester.
– Stand on suitable rubber mats (obtained locally, if necessary) to insulate you
from grounds such as metal floor strips and machine frames.
Observe the special safety precautions when you work with very high voltages;
Instructions for these precautions are in the safety sections of maintenance
information. Use extreme care when measuring high voltages.
v
Regularly inspect and maintain your electrical hand tools for safe operational
condition.
v
Do not use worn or broken tools and testers.
v
Never assume that power has been disconnected from a circuit. First, check that it
has been powered off.
v
Always look carefully for possible hazards in your work area. Examples of these
hazards are moist floors, nongrounded power extension cables, power surges,
and missing safety grounds.
v Do not touch live electrical circuits with the reflective surface of a plastic dental
mirror. The surface is conductive; such touching can cause personal injury and
machine damage.
Safety information
Introduction
17