Electrical safety

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 main units

•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. Attention: 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.

Attention: An electrical shock can occur only when there is a complete circuit. By observing the above rule, you may prevent a current from passing through your body.

–When using testers, 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; Instructions for these precautions 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

–Similar units to listed above

This practice ensures correct grounding of the units.

• If an electrical accident occurs:

2Hardware Maintenance Manual

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Lenovo L420, L421, L520 manual Electrical safety
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L420, L520, L421 specifications

The Lenovo L421, L520, and L420 are part of Lenovo's ThinkPad series, which is known for its reliability, durability, and performance. These models are designed primarily for business professionals and students, providing a blend of functionality and portability tailored for everyday computing.

The Lenovo L421 is equipped with the second-generation Intel Core processors, which enhance its performance and efficiency. It features a 14-inch LED backlit display, offering sharp visuals and sufficient screen real estate for multitasking. The L421 also sports a spill-resistant keyboard, ensuring that accidental spills do not affect the device's functionality. This model supports up to 8GB of RAM and incorporates various connectivity options, including USB 3.0 ports, HDMI, and an SD card reader, which makes it versatile for various peripherals.

The L520 is another solid offering from Lenovo, featuring a slightly larger 15.6-inch display for increased productivity. It shares many characteristics with the L421, such as the use of Intel’s second-generation processors. The L520 also emphasizes security with features like a fingerprint reader and a Trusted Platform Module (TPM) for data encryption, appealing to businesses that require stringent security measures. Its ExpressCard and docking station compatibility add flexibility, allowing users to tailor their setups according to their needs.

The L420, like its siblings, comes with an emphasis on performance and utility. With a 14-inch HD display, it offers vibrant visuals. The L420 also benefits from Lenovo's legendary keyboard design, which ensures a comfortable typing experience. This model is geared for users who require a balance between performance and portability without compromising on essential features. The same Intel Core processors and security features are incorporated, ensuring a reliable experience for professional applications.

All three models feature Lenovo's innovative Power Management technology, which optimizes battery life, allowing users to work longer hours without needing to recharge. Additionally, they are built with robust materials that ensure longevity, making them suitable for both office and on-the-go environments.

Overall, the Lenovo L421, L420, and L520 exemplify the ThinkPad series' commitment to performance, security, and durability, making them excellent choices for anyone looking for reliable laptops for professional use.
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