IBM ThinkPad R30 Hardware Maintenance Manual page 19

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:
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:
cause electrical shock. 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; these instructions 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.
Another person must be there to switch
There must be a complete circuit to
ThinkPad R30 and R31
13