IBM THINKPAD A20M, Hardware Maintenance Manual

Page: 22 / 158

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.
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.
Safety inspection guide
The purpose of this inspection guide is to assist you in
identifying potentially unsafe conditions. As each machine
was designed and built, required safety items were
installed to protect users and service personnel from injury.
This guide addresses only those items. You should use
good judgment to identify potential safety hazards due to
attachment of non-IBM features or options not covered by
this inspection guide.
If any unsafe conditions are present, you must determine
how serious the apparent hazard could be and whether
you can continue without first correcting the problem.
Consider these conditions and the safety hazards they
present:
v
Electrical hazards, especially primary power (primary
voltage on the frame can cause serious or fatal
electrical shock)
v
Explosive hazards, such as a damaged CRT face or a
bulging capacitor
Safety information
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ThinkPad A20m/p, A21m/p, A22m/p