Table 1. FRU tests (continued)

FRU

Applicable test

 

 

 

Optical drive

1.

Diagnostics ➙ Other Devices ➙ Optical Drive

 

2.

Interactive Tests ➙ Optical Drive Test

Memory

1.

If two DIMMs are installed, remove one of them and run Diagnostics ➙ Advanced

 

 

Memory Tests.

 

2.

If the problem does not recur, return the DIMM to its place, remove the other one,

 

 

and run the test again.

 

 

TrackPoint or pointing

If the TrackPoint does not work, check the configuration as specified in the BIOS Setup

device

Utility. If the TrackPoint is disabled, select Automatic to enable it.

 

After you use the TrackPoint, the pointer may drift on the screen for a short time. This

 

drift can occur when a slight, steady pressure is applied to the TrackPoint pointer.

 

This symptom is not a hardware problem. If the pointer stops after a short time, no

 

service action is necessary.

 

If enabling the TrackPoint does not correct the problem, continue with the following:

 

• Interactive Tests ➙ Mouse

Touch Pad

If the Touch Pad does not work, check the configuration as specified in the BIOS Setup

 

Utility. If the Touch Pad is disabled, select Automatic to enable it. If enabling the Touch

 

Pad does not correct the problem, continue with the following:

 

• Interactive Tests ➙ Mouse

Power system checkout

To verify a symptom, do the following:

1.Turn off the computer.

2.Remove the battery pack.

3.Connect the ac power adapter.

4.Check that power is supplied when you turn on the computer.

5.Turn off the computer.

6.Disconnect the ac power adapter and install the charged battery pack.

7.Check that the battery pack supplies power when you turn on the computer.

If you suspect a power problem, see the appropriate one of the following power supply checkouts:

•“Checking the ac power adapter” on page 34

•“Checking operational charging” on page 35

•“Checking the battery pack” on page 35

•“Checking the backup battery” on page 36

Checking the ac power adapter

You are here because the computer fails only when the ac power adapter is used.

•If the power problem occurs only when the docking station or the port replicator is used, replace the docking station or the port replicator.

•If the power-on indicator does not turn on, check the power cord of the ac power adapter for correct continuity and installation.

•If the computer does not charge during operation, go to “Checking operational charging” on page 35.

To check the ac power adapter, do the following:

1.Unplug the ac power adapter cable from the computer.

2.Measure the output voltage at the plug of the ac power adapter cable. See the following figure:

34Hardware Maintenance Manual

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Lenovo L520, L421, L420 manual Power system checkout, Checking the ac power adapter
Page 39 Page 41

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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