Lenovo 3000 C305 All-In-One - Manual (Page 8)

Hardware Maintenance Manual
6
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.
Remember: 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.
Remember: There must be a complete circuit to 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.
Regularly inspect and maintain your electrical hand tools for safe •
operational condition.
Do not use worn or broken tools and testers.
•
Never assume • that power has been disconnected from a circuit. First,
check that it has been powered-off.
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.
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.
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.)
If an electrical accident occurs: •
– Use caution; do not become a victim yourself.
– Switch off power.
– Send another person to get medical aid.