IBM ThinkPad T21, Hardware Maintenance Manual

Page: 20 / 182

v
After service, reinstall all safety shields, guards, labels,
and ground wires. Replace any safety device that is
worn or defective.
v
Reinstall all covers correctly before returning the
machine to the customer.
Electrical safety
Observe the following rules when working on electrical
equipment.
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 main units
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.
Safety information
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ThinkPad T20, T21, T22, T23 (MT 2647/2648)