General safety. Lenovo E73z, 10Bl

Chapter 2. Safety information

This chapter contains the safety information that you need to be familiar with before servicing a computer.

General safety

Follow these rules to ensure general safety:

• Observe good housekeeping in the area of the machines during and after maintenance.

• When lifting any heavy object:

1. Ensure you can stand safely without slipping.

2. Distribute the weight of the object equally between your feet.

3. Use a slow lifting force. Never move suddenly or twist when you attempt to lift.

4. Lift by standing or by pushing up with your leg muscles; this action removes the strain from the muscles in your back.

Attention: Do not attempt to lift any objects that weigh more than 16 kg (35 lb) or objects that you think are too heavy for you.

• Do not perform any action that causes hazards to the customer, or that makes the equipment unsafe.

• Before you start the machine, ensure that other service representatives and the customer's personnel are not in a hazardous position.

• Place removed covers and other parts in a safe place, away from all personnel, while you are servicing the machine.

• Keep your tool case away from walk areas so that other people will not trip over it.

• Do not wear loose clothing that can be trapped in the moving parts of a machine. Ensure that your sleeves are fastened or rolled up above your elbows. If your hair is long, fasten it.

• Insert the ends of your necktie or scarf inside clothing or fasten it with a nonconductive clip, approximately

8 centimeters (3 inches) from the end.

• Do not wear jewelry, chains, metal-frame eyeglasses, or metal fasteners for your clothing.

Remember: Metal objects are good electrical conductors.

• Wear safety glasses when you are: hammering, drilling, soldering, cutting wire, attaching springs, using solvents, or working in any other conditions that might be hazardous to your eyes.

• After service, reinstall all safety shields, guards, labels, and ground wires. Replace any safety device that is worn or defective.

• Reinstall all covers correctly before returning the machine to the customer.

Electrical safety

CAUTION:

Electrical current from power, telephone, and communication cables can be hazardous. To avoid personal injury or equipment damage, disconnect the attached power cords, telecommunication systems, networks, and modems before you open the computer covers, unless instructed otherwise in the installation and configuration procedures.

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Observe the following rules when working on electrical equipment.

Important: Use only approved tools and test equipment. Some hand tools have handles covered with a soft material that does not insulate you when working with live electrical currents. Many customers have, near their equipment, rubber floor mats that contain small conductive fibers to decrease electrostatic discharges.

Do not use this type of mat to protect yourself from electrical shock.

• Find the room emergency power-off (EPO) switch, disconnecting switch, or electrical outlet. If an electrical accident occurs, you can then operate the switch or unplug the power cord quickly.

• Do not work alone under hazardous conditions or near equipment that has hazardous voltages.

• Disconnect all power before:

– Performing a mechanical inspection

– Working near power supplies

– Removing or installing Field Replaceable Units (FRUs)

• Before you start to work on the machine, unplug the power cord. If you cannot unplug it, ask the customer to power-off the wall box that supplies power to the machine and to lock the wall box in the off position.

• If you need to work on a machine that has exposed electrical circuits, observe the following precautions:

– Ensure that another person, familiar with the power-off controls, is near you.

Remember: Another person must be there to switch off the power, if necessary.

– Use only one hand when working with powered-on electrical equipment; keep the other hand in your pocket or behind your back.

Remember: There must be a complete circuit to cause electrical shock. By observing the above rule, you may prevent a current from passing through your body.

– When using a tester, set the controls correctly and use the approved probe leads and accessories for that tester.

– Stand on suitable rubber mats (obtained locally, if necessary) to insulate you from grounds such as metal floor strips and machine frames.

Observe the special safety precautions when you work with very high voltages; these instructions are in the safety sections of maintenance information. Use extreme care when measuring high voltages.

• Regularly inspect and maintain your electrical hand tools for safe operational condition.

• Do not use worn or broken tools and testers.

• Never assume that power has been disconnected from a circuit. First, check that it has been powered-off.

• Always look carefully for possible hazards in your work area. Examples of these hazards are moist floors, nongrounded power extension cables, power surges, and missing safety grounds.

• Do not touch live electrical circuits with the reflective surface of a plastic dental mirror. The surface is conductive; such touching can cause personal injury and machine damage.

• Do not service the following parts with the power on when they are removed from their normal operating places in a machine:

– Power supply units

– Pumps

– Blowers and fans

– Motor generators and similar units. (This practice ensures correct grounding of the units.)

• If an electrical accident occurs:

– Use caution; do not become a victim yourself.

– Switch off power.

4 ThinkCentre E73z Hardware Maintenance Manual