Chapter 7. FRU replacement notices

This chapter presents notices related to removing and replacing parts. Read this chapter carefully before replacing any FRU.

Screw notices

Loose screws can cause a reliability problem. In the ThinkPad Notebook, this problem is addressed with special nylon-coated screws that have the following characteristics:

•They maintain tight connections.

•They do not easily come loose, even with shock or vibration.

•They are harder to tighten.

•Each one should be used only once.

Do the following when you service this machine:

•Keep the screw kit (for the P/N, see “Miscellaneous parts” on page 153) in your tool bag.

•Always use new screws.

•Use a torque screwdriver if you have one.

Tighten screws as follows:

•Plastic to plastic

Turn an additional 90 degrees after the screw head touches the surface of the plastic part:

•Logic card to plastic

Turn an additional 180 degrees after the screw head touches the surface of the logic card:

•Torque driver

If you have a torque driver, refer to the “Torque” column for each step.

•Make sure that you use the correct screw. If you have a torque screwdriver, tighten all screws firmly to the torque shown in the table. Never use a screw that you removed. Use a new one. Make sure that all of the screws are tightened firmly.

•Ensure torque screw drivers are calibrated correctly following country specifications.

© Copyright Lenovo 2011

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Lenovo L420, L421, L520 manual FRU replacement notices, Screw notices
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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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