Lenovo MT 1871 Hardware Maintenance Manual page 22

Safety information
– 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:
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.
v Do not service the following parts with the power on
when they are removed from their normal operating
places in a machine:
– Power supply units
– Pumps
– Blowers and fans
– Motor generators
and similar units. (This practice ensures correct
grounding of the units.)
v If an electrical accident occurs:
– Use caution; do not become a victim yourself.
– Switch off power.
– Send another person to get medical aid.
18
R50/R50p, R51 Series
Another person must be there to switch
An electrical shock can occur only when