POST error codes
Each time you turn the computer on, it performs a series of tests to check that the system is operating
correctly and that certain options are set. This series of tests is called the Power-On Self-Test, or POST.
POST does the following:
• Checks some basic system-board operations
• Checks that the memory is working correctly
• Starts video operations
• Veries that the boot drive is working
POST Error Message Description/Action
Keyboard error
Cannot initialize the keyboard. Make sure the keyboard
is properly connected to the computer and that no keys
are held pressed during POST. To purposely congure
the computer without a keyboard, select Keyboardless
operation in Startup option to Enabled. The BIOS then
ignores the missing keyboard during POST.
Reboot and Select proper Boot device or Insert Boot
Media in selected Boot device
The BIOS was unable to nd a suitable boot device. Make
sure the boot drive is properly connected to the computer.
Make sure you have bootable media in the boot device.
Undetermined problems
1. Power-off the computer.
2. Remove or disconnect the following components (if connected or installed) one at a time.
a. External devices (modem, printer, or mouse)
b. Extended video memory
c. External Cache
d. External Cache RAM
e. Hard disk drive
f. Disk drive
3. Power-on the computer to re-test the system.
4. Repeat steps 1 through 3 until you nd the failing device or component.
If all devices and components have been removed and the problem continues, replace the system board.
20 Lenovo H520sHardware Maintenance Manual
