Lenovo E420 Laptop User Manual


 
Power problems
Print these instructions now and keep it with your computer for reference later.
If your computer is getting no power at all, check the following items:
1. Verify the power switch. Refer to “System-status indicators” on page 12. The power switch is
illuminated whenever the computer is on.
2. Check all power connections. Remove any power strips and surge protectors to connect the ac power
adapter directly to the ac power outlet.
3. Inspect the ac power adapter. Check for any physical damage, and make sure that the power cable is
rmly attached to the adapter brick and the computer.
4. Verify the ac power source is working by attaching another device to the outlet.
5. Remove all devices and then test for system power with minimal devices attached.
a. Disconnect the ac power adapter and all cables from the computer.
b. Close the computer display, and turn the computer over.
c. Remove the battery. Refer to “Replacing the battery” on page 77.
d. Remove the memory (SO-DIMM). Refer to “Replacing memory” on page 93.
e. Remove the PCI Express Mini Card. Refer to “Installing and replacing a PCI Express Mini Card for
wireless LAN/WiMAX connection” on page 90.
f. Remove the hard disk drive. Refer to “Replacing the hard disk drive” on page 79 .
g. Wait for 30 seconds, and then reinstall the SO-DIMM and the known good battery or the ac power
adapter to test the computer with minimal devices attached rst.
h. Reinstall each device one at a time that you have removed in the earlier steps.
If your computer does not run on battery power, check the following items:
1. Remove and reseat the battery to make sure that it is properly connected. Refer to “Replacing the
battery” on page 77
.
2. Swap batteries with another similar model, if available.
If another similar ThinkPad model is available, then verify that the battery pack works in the other
computer and that the battery pack for the other model works in this computer.
3. Verify the battery-status indicator. Refer to “Power-status indicators” on page 13.
A power button problem
Problem: The system does not respond, and you cannot turn off the computer.
Solution: Turn off the computer by pressing and holding the power button for 4 seconds or more. If the
system is still not reset, remove the ac power adapter and the battery.
Startup problems
Print these instructions now and keep them with your computer for reference later.
If you receive an error message before the operating system loads, check the following item:
Follow the appropriate corrective actions for Power-on self-test error messages.
If you receive an error message while the operating system is loading the desktop conguration after the
POST is completed, check the following items:
1. Visit the Lenovo Support Web site at http://www.lenovo.com/think/support and search for the error
message.
152 User Guide