IBM ThinkPad R40 2681 Hardware Maintenance Manual

Also see for ThinkPad R40: Special instructions User guide User manual Setup guide Hardware Maintenance Manual

Contents

If any unsafe conditions are present, you must determinehow serious the apparent hazard could be and whetheryou can continue without first correcting the problem.Consider these conditions and the safety hazards theypresent:v Electrical hazards, especially primary power (primaryvoltage on the frame can cause serious or fatalelectrical shock)v Explosive hazards, such as a damaged CRT face or abulging capacitorv Mechanical hazards, such as loose or missing hardwareTo determine whether there are any potentially unsafeconditions, use the following checklist at the beginning ofevery service task. Begin the checks with the power off,and the power cord disconnected.Checklist:1. Check exterior covers for damage (loose, broken, orsharp 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 groundcontinuity for 0.1 ohm or less between the externalground pin and frame ground.b. The power cord should be the type specified in theparts list.c. Insulation must not be frayed or worn.4. Remove the cover.5. Check for any obvious non-IBM alterations. Use goodjudgment as to the safety of any non-IBM alterations.6. Check inside the unit for any obvious unsafeconditions, such as metal filings, contamination, wateror 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 (screwsor rivets) have not been removed or tampered with.Handling devices that are sensitive toelectrostatic dischargeAny computer part containing transistors or integratedcircuits (ICs) should be considered sensitive to electrostaticdischarge (ESD.) ESD damage can occur when there is adifference in charge between objects. Protect against ESDSafety information20 ThinkPad R40