Power system checkout, Checking the ac power adapter – Lenovo E40-70 Notebook User Manual

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• Plastic parts, latches, pins, or connectors that have been cracked or broken by excessive force
• Damage caused by liquid spilled into the system
• Damage caused by the improper insertion of a personal-computer card (PC card) or the installation of

an incompatible card

• Improper disc insertion or use of an external optical drive
• Fuses blown by attachment of a non-supported device
• Forgotten computer password (making the computer unusable)
• Sticky keys caused by spilling a liquid onto the keyboard
• Use of an incorrect ac power adapter on laptop products

The following symptoms might indicate damage caused by non-warranted activities:
• Missing parts might be a symptom of unauthorized service or modification.
• Check for obvious damage to a hard disk drive. If the spindle of a hard disk drive becomes noisy, the hard

disk drive might have been dropped or subject to excessive force.

Power system checkout

To verify if a battery pack or an ac power adapter is functional, do the following:

1. Turn off the computer.
2. Connect the ac power adapter.
3. Turn on the computer. If the computer can be turned on, it means that either the battery pack or the ac

power adapter is functional.

4. Insert a straightened paper clip into the novo button to reset the computer. If the computer is still

powered on, it means that the ac power adapter is functional.

5. Turn off the computer.
6. Disconnect the ac power adapter and turn on the computer. If the computer can be turned on, it

means that the battery pack is functional.

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

“Checking the ac power adapter” on page 22

“Checking the external battery pack and the operational charging” on page 23

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 adapter for correct continuity

and installation.

• If the computer does not charge during operation, go to “Checking the external battery pack and the

operational charging” on page 23.

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 illustration:

Pin

Voltage (V dc)

1

+20

2

0

3

Ground

(20V)

1

3

2

22

Hardware Maintenance Manual

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