Category: Laptop Repair and Service
Contents of this article
- How to test the AC adapter
- How to test the RTC battery
- How to remove passwords
Lenovo ThinkPad Yoga 15
Power system checkout
To verify a power symptom, 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
emergency reset hole 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.
Checking the built-in battery and operational
charging”
“Checking the coin-cell battery”
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 system status indicator does not
blink three times when an ac power source is connected, check the power cord of
the ac power adapter for correct continuity and installation.
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
Note: Output voltage of pin 2 of the ac power adapter might differ from
the one you are servicing.
3. If the voltage is not correct, replace the
ac power adapter.
4. If the voltage is acceptable, replace the
system board.
Note: Noise from the ac power adapter does not always indicate a defect.
Checking the built-in battery and operational charging
Note: Noise from the ac power adapter does not always indicate a defect.
Checking the built-in battery and operational charging
This computer supports only batteries
specially designed for this specific system and manufactured by Lenovo or an
authorized builder. The system does not support unauthorized batteries or
batteries designed for other systems. If an unauthorized battery or a battery
designed for another systems is installed, the system will not charge.
To check for detailed battery status information, do the following:
To check for detailed battery status information, do the following:
For 7: Open the Power Manager
program and click the Battery tab.
For 8.1: Open the Lenovo Settings
program and click OK.
To check whether the battery charges properly
during operation, do the following:
1. Discharge the battery until the remained
battery power is less than 50%.
2. Connect the computer to ac power to charge
the battery.
If the battery status icon in the Windows
notification area indicates that the battery is not charging, remove the
battery and let it return to room temperature.
3. Reinstall the battery. If the battery is
still not charging, replace the battery pack.
4. Check the battery status icon again. If
the same error still exists, replace the system board.
Checking the coin-cell battery
To check the coin-cell battery, do the
following:
1. Disconnect the battery connector.
2. Remove the coin-cell battery.
Measure the voltage of the coin-cell battery.
See the following illustration
If the voltage is correct, replace the system
board.
If the voltage is not correct, replace the
coin-cell battery.
If the coin-cell battery discharges quickly
after replacement, replace the system board.
How to remove the power-on
password
If a supervisor password has been set and is
known to the service technician, do the following to remove the power-on
password:
1. Turn on the computer.
2. When the ThinkPad logo comes up,
immediately press F1.
3. Type the supervisor password to enter the
ThinkPad Setup program.
4. Select Security.
5. Select Password.
6. Select Power-On Password.
7. Type the current supervisor password in
the Enter Current Password field. Then leave the Enter
New Password field blank, and press Enter twice.
New Password field blank, and press Enter twice.
8. In the Changes have been saved window,
press Enter.
9. Press F10 to save changes and exit the
ThinkPad Setup program.
How to remove the hard disk
password
To remove a user hard disk password that has
been forgotten, when the supervisor password and master hard disk password are
known, do the following:
1. Turn on the computer.
2. When the ThinkPad logo comes up,
immediately press F1 to enter the ThinkPad Setup program.
3. Select Security.
4. Select Password.
5. Select Hard-disk x password,
where x is the letter of the hard disk drive. A pop-up window opens.
6. Select Master hard disk password.
7. Type the current master hard disk password
in the Enter Current Password field. Then leave the Enter
New Password field blank, and press Enter twice.
New Password field blank, and press Enter twice.
8. Press F10. 9. Press F10 to save changes
and exit the ThinkPad Setup program.
The user hard disk password and the master
hard disk password have been removed.
