Lenovo ThinkPad T400s 2823 Hardware Maintenance Manual

Contents

Electrical safetyObserve the following rules when working on electrical equipment.v Find the room emergency power-off (EPO) switch, disconnecting switch, orelectrical outlet. If an electrical accident occurs, you can then operate the switchor unplug the power cord quickly.v Do not work alone under hazardous conditions or near equipment that hashazardous voltages.v Disconnect all power before:– Performing a mechanical inspection– Working near power supplies– Removing or installing main unitsv Before you start to work on the machine, unplug the power cord. If you cannotunplug it, ask the customer to power-off the wall box that supplies power to themachine, and to lock the wall box in the off position.v If you need to work on a machine that has exposed electrical circuits, observe thefollowing precautions:– Ensure that another person, familiar with the power-off controls, is near you.Attention: Another person must be there to switch off the power, ifnecessary.– Use only one hand when working with powered-on electrical equipment;keep the other hand in your pocket or behind your back.Attention: An electrical shock can occur only when there is a completecircuit. By observing the above rule, you may prevent a current from passingthrough your body.– When using testers, set the controls correctly and use the approved probeleads and accessories for that tester.– Stand on suitable rubber mats (obtained locally, if necessary) to insulate youfrom grounds such as metal floor strips and machine frames.Observe the special safety precautions when you work with very high voltages;Instructions for these precautions are in the safety sections of maintenanceinformation. Use extreme care when measuring high voltages.v Regularly inspect and maintain your electrical hand tools for safe operationalcondition.v Do not use worn or broken tools and testers.v Never assume that power has been disconnected from a circuit. First, check that ithas been powered off.v Always look carefully for possible hazards in your work area. Examples of thesehazards are moist floors, nongrounded power extension cables, power surges,and missing safety grounds.Important:Use only approved tools and test equipment. Some hand tools have handlescovered with a soft material that does not insulate you when working with liveelectrical currents.Many customers have, near their equipment, rubber floor mats that contain smallconductive fibers to decrease electrostatic discharges. Do not use this type of matto protect yourself from electrical shock.Safety information 3