Lenovo Yoga A940 User Manual page 48

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.
8. Check that the power-supply cover fasteners (screws or rivets) have not been
removed or tampered with.
„ Handling electrostatic discharge-sensitive devices
Any computer part containing transistors or integrated circuits (ICs) should be
considered sensitive to electrostatic discharge (ESD). ESD damage can occur when
there is a difference in charge between objects. To protect against ESD damage,
equalize the charge between objects. Then, the machine, the part, the work mat, and
the person handling the part are all at the same charge.
Notes:
1. Use product-specific ESD procedures when they exceed the requirements noted
here.
2. Make sure that the ESD protective devices you use have been certified (ISO 9000)
as fully effective.
When handling ESD-sensitive parts:
• Keep the parts in protective packages until they are inserted into the product.
• Avoid contact with other people while handling the part.
• Wear a grounded wrist strap against your skin to eliminate static on your body.
• Prevent the part from touching your clothing. Most clothing is insulative and retains a
charge even when you are wearing a wrist strap.
• Use the black side of a grounded work mat to provide a static-free work surface.
The mat is especially useful when handling ESD-sensitive devices.
• Select a grounding system, such as those listed below, to provide protection that
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