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
– 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 intent of this inspection guide is to assist you in
identifying 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.
Consider these conditions and the safety hazards they
v Electrical hazards, especially primary power (primary
voltage on the frame can cause serious or fatal
v Explosive hazards, such as a damaged CRT face or
v Mechanical hazards, such as loose or missing
The guide consists of a series of steps presented in a
checklist. Begin the checks with the power off, and the
power cord disconnected.
1. Check exterior covers for damage (loose, broken, or
2. Power-off the computer. Disconnect the power cord.
3. Check the power cord for:
a. A third-wire ground connector in good condition.
Use a meter to measure third-wire ground
ThinkPad R30 and R31 HMM