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Service Hints & Tips

Document ID: GSMH-3BFL7C

TP 755CD/CDV - Power Management Features

Applicable to: World-Wide

Power Management Features:
Three power management modes are provided by the computer to save 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.
- The CPU clock is set to the lowest speed.

Events that cause entering of standby mode:
Standby requested by the Fn key. (Fn+ F3) No activity under auto-standby enabled by the feature utility.

Events that cause exiting or resuming of standby mode:
(Resume) Any key operation.

Suspend Mode:
When the computer. enters the suspend mode, the following occurs:
- The LCD backlight turns off.
- The LCD power is powered-off.
- The hard disk is powered-off.
- The CPU clock is set to the lowest speed.
- The CPU is stopped.

In the ThinkPad Features Program, the computer can be set to "Will not suspend even if LCD is closed". When the computer is powered with ac power and is used with one of the following IBM PC cards, the computer will only enter the standby mode. The PC card and application program remain active.
- 3270 Emulation Credit Card Adapter
- 5250 Emulation Credit Card Adapter
- Token-Ring 16/4 Credit Card Adapter
- Credit Card Adapter for Ethernet

The following conditions prevent the computer from entering the suspend mode.
While the communication link is running. When a serial mouse or external pointing device has been selected in the Config menu of the Easy-Setup.

Events that cause the computer. to enter the suspend mode:
- Suspend mode is requested by the Fn key (Fn+ F4).
- The LCD is closed.
- The keyboard is opened.
- The specified time has elapsed from the last operation with the keyboard, mouse, hard disk drive, parallel connector, diskette drive, or the AC Adapter is plugged in. The time is specified by Suspend Timer in the ThinkPad Features program.
- The battery condition is low. The battery power indicator blinks (orange).
- The PS2 OFF command is set in the ThinkPad Features program.

Events that cause exiting or resuming of the suspend mode:
- (Resume) The LCD is opened.
- (Resume) The keyboard is closed.
- (Resume) Real time clock alarm signaled.
- (Resume) Ring indicator (RI) signaled by serial or PCMCIA device.
- (Resume) The Fn key is pressed.
- (Exit) Timer conditions are satisfied to enter hibernation mode.

Hibernation Mode:
When in hibernation mode, the following occurs:
The system status, RAM, VRAM, and setup data are stored on the hard disk. The system is powered-off.

Events that prevent the computer from entering the hibernation mode.
A serial mouse or external pointing device has been selected in the Config menu of the Easy-Setup. The computer is powered with ac power and one of the following IBM PC cards is used.
- PCMCIA Data/FAX Modem
- High Speed PCMCIA Data/FAX Modem
- 3270 Emulation Credit Card Adapter
- 5250 Emulation Credit Card Adapter
- Token-Ring 16/4 Credit Card Adapter
- Credit Card Adapter for Ethernet

Events that cause the computer. to enter the hibernation mode:
- Pressing the Fn key (Fn+ F12).
- Timer conditions are satisfied in suspend mode.

Critical low battery condition:
Event that causes the &c. to exit the hibernation mode. The power-on switch is operated.

When power is turned on, the hibernation history of the boot record on the hard disk is recognized and system status is restored from the hard disk to resume operation.

Port Replicator Power Overload:
If intermittent power shut-downs occur while using PCMCIA-2 devices through a port replicator, suspect an over-current problem. Some PCMCIA devices use too much power, and if the maximum usage of each device occurs simultaneously, the
total current could exceed the replicator limit, thereby causing a power shut down. Remove each device one at a time and repeat the sequence until problem fails to return. Ten determine the cause.

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	Hint Category	Hardware Maintenance Information
	Date Created	15-11-96
	Last Updated	01-04-98
	Revision Date	13-03-99
	Brand	IBM ThinkPad
	Product Family	ThinkPad 755CD, ThinkPad 755CDV
	Machine Type	9545
	Model	Various
	TypeModel
	Retain Tip (if applicable)	N/A
	Reverse Doclinks and Admin Purposes