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. Regu-
larly 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 your-
self.
–Switch off power.
–Send another person to get medical aid.
Safety Inspection Guide
The intent of this inspection guide is to assist you in identi-
fying potentially unsafe conditions on these products. Each
machine, as it was designed and built, had required safety
items installed to protect users and service personnel from
injury. This guide addresses only those items. However,
good judgment should be used 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. Con-
sider these conditions and the safety hazards they present:
Electrical hazards, especially primary power (primary
voltage on the frame can cause serious or fatal elec-
trical shock).
14 ThinkPad 390X / i 1700 HMM