Lenovo 20L5, Hardware Maintenance Manual, Page: 41 / 114

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.
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.
Power management
To reduce power consumption, the computer has three power management modes: screen blank, sleep, and
hibernation.
Sleep mode
When the computer enters sleep mode, the following events occur in addition to what occurs in screen blank
mode:
• The LCD is powered off.
• The hard disk drive or solid-state drive is powered off.
• The microprocessor stops.
To put your computer into sleep mode, press Fn+4 or open the Start menu, click Power , and then click
Sleep . To return to normal operation, press the Fn key only.
In certain circumstances, the computer goes into sleep mode automatically:
• After a period of inactivity specified in power plan settings
• When the battery power is low
Hibernation mode
In hibernation mode, the following occurs:
• The system status, random access memory (RAM), video random access memory (VRAM), and setup data
are stored on the hard disk drive or solid-state drive.
• The system is powered off.
Note: If the computer enters the hibernation mode while it is docked to the docking station or the port
replicator, do not undock it before resuming normal operation. If you do undock it and then try to resume
normal operation, you will get an error message, and you will have to restart the system.
If you have defined one of the following actions as the event that causes the system to go into hibernation
mode, perform that action.
• Closing the lid.
• Pressing the power button.
Also, the computer goes into hibernation mode automatically after a period of inactivity specified in power
plan settings.
When the power is turned on, the computer returns from hibernation mode and resumes operation. The
hibernation file in the boot record on the hard disk drive or solid-state drive is read, and system status is
restored from the hard disk drive or solid-state drive.
Symptom-to-FRU index
This section contains following information:
• “Numeric error codes” on page 36
Chapter 4
.
Related service information
35