Lenovo 11A9000DGE, Hardware Maintenance Manual

Page: 9 / 118

• 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.
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 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:
• Electrical hazards, especially primary power (primary voltage on the frame can cause serious or fatal
electrical shock).
• Explosive hazards, such as a damaged CRT face or bulging capacitor
• Mechanical hazards, such as loose or missing hardware
The guide consists of a series of steps presented in a checklist. Begin the checks with the power off, and the
power cord disconnected.
Checklist:
1. Check exterior covers for damage (loose, broken, or sharp edges).
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
continuity for 0.1 ohm or less between the external ground pin and frame ground.
b. The power cord should be the appropriate type as specified in the parts listings.
c. Insulation must not be frayed or worn.
4. Remove the cover.
5. Check for any obvious alterations. Use good judgment as to the safety of any alterations.
6. Check inside the unit for any obvious unsafe conditions, such as metal filings, contamination, water or
other liquids, or signs of fire or smoke damage.
7. Check for worn, frayed, or pinched cables.
Chapter 1
.
Important safety information
3