IBM 2621421 Hardware Maintenance Manual - Page 22

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 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 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. 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. 14 ThinkPad i Series 1400 HMM