Lenovo M50-70 Notebook - Manual (Page 9)

5
Safety information
Safety inspection guide
The purpose of this inspection guide is to assist you in identifying potential
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 according to the attachment of non-Lenovo 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 a bulging capacitor
• Mechanical hazards, such as loose or missing hardware
To determine whether there are any potential unsafe conditions, use the
following checklist at the beginning of every service task. 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. Turn 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 the frame ground.
b. The power cord should be the type specified in the parts list.
c. Insulation must not be frayed or worn.
4. Check for cracked or bulging batteries.
5. Remove the cover.
6. Check for any obvious non-Lenovo alterations. Use good judgment as to the
safety of any non-Lenovo alterations.
7. 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.
8. Check for worn, frayed, or pinched cables.
9. Check that the power-supply cover fasteners (screws or rivets) have not
been removed or tampered with.