Handling Devices That Are Sensitive To Electrostatic Discharge - IBM ThinkPad R40 Hardware Maintenance Manual

Safety information
If any unsafe conditions are present, you m ust determ ine
how serious the apparent hazard could be and whether
you can continue w ithout first correcting the problem.
C onsider these conditions and the safety hazards they
present:
• Electrical hazards, especially primary power (prim ary
voltage on the frame can cause serious or fatal
electrical shock)
• Explosive hazards, such as a dam aged CRT face or a
bulging capacitor
• M echanical hazards, such as loose or missing hardware
To determ ine whether there are any potentially 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 dam age (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 m eter to m easure 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 type specified in the
parts list.
c. Insulation m ust not be frayed or worn.
4. Remove the cover.
5. Check for any obvious non-IBM alterations. Use good
judgm ent as to the safety of any non-IBM alterations.
6. Check inside the unit for any obvious unsafe
conditions, such as metal filings, contam ination, w ater
or other liquids, or signs of fire or sm oke 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 tam pered with.
Handling devices that are sensitive to
electrostatic discharge
Any com puter 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
2 0 ThinkPad R40