6. Measure the voltage of the backup battery. Refer to
the following table for voltages:
If the voltage is correct, replace the system board.
If the voltage is not correct, the backup battery has
been discharged. Replace the backup battery.
If the backup battery discharges quickly after
replacement, replace the system board.
Wire Voltage (V dc)
+ +2.5 to +3.7
−Ground
Power Management Features
Three power management modes are provided by the
computer to reduce power consumption and prolong
battery power.
Standby Mode: When in standby mode the following
occurs:
The LCD backlight turns off.
The hard disk motor stops.
Events that cause the computer to enter standby mode:
Standby requested by the Fn key. (Fn+F3)
No activity under auto-standby enabled by the
ThinkPad Features program.
Events that cause the computer to exit or resume standby
mode:
(Resume) Any key operation.
Suspend Mode: When in suspend mode, the
following, in addition to the two actions of standby mode,
occur:
The LCD is powered off.
The hard disk is powered off.
The CPU is stopped.
Notes
1. In the ThinkPad Features Program, the computer
can be set to “Will not suspend even if LCD is
closed.”
2. When the computer is powered with ac power
and is used with one of the communication PC
cards, the computer enters
standby mode
; the
PC card and application program remain active.
3. The computer cannot enter suspend mode while
a communication link is running.
104 IBM Mobile Systems - ThinkPad HMM Volume 3