Monday, May 09, 2016

Lenovo ThinkPad P40 Yoga – How to replace the keyboard – How to test the power supply – How to test the battery pack – Laptop repair and Service

Category: Laptop Repair and Servcie 

Contents of this article 

  • How to test the AC adapter
  • How to remove the Key board 
  • How to test the battery pack 

Lenovo ThinkPad P40 Yoga 

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.
If you suspect a power problem, see the appropriate one of the following power supply checkouts:
“Checking the ac power adapter”
“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.
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:
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
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.
3. 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 Keyboard
Remove the screws that secure the keyboard.
Push hard in the direction shown by the arrows to unlatch the front edge of the keyboard (the edge that is close to you).
Note: Depending on the model, your computer might look different from the following illustration.
Pivot the keyboard slightly upward as shown by the arrow .Then turn over the keyboard as shown by the arrow.
Note: Depending on the model, your computer might look different from the following illustration.
Detach the connectors and remove the keyboard.