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 non-IBM alterations. Use good
judgment as to the safety of any non-IBM 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
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.
Protect against ESD damage by equalizing the charge so
that the machine, the part, the work mat, and the person
handling the part are all at the same charge.
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:
v Keep the parts in protective packages until they are
inserted into the product.
v Avoid contact with other people.
v Wear a grounded wrist strap against your skin to
eliminate static on your body.
v Prevent the part from touching your clothing. Most
clothing is insulative and retains a charge even when
you are wearing a wrist strap.
v 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.
v Select a grounding system, such as those listed below,
to provide protection that meets the specific service
Note: The use of a grounding system is desirable but
not required to protect against ESD damage.
ThinkPad R30 and R31