Lenovo 2765PAU - ThinkPad T400 14.1" Notebook, Service Manual, Page: 33 / 94

Sleep (standby) or hibernation problems
Problem:
The computer enters sleep (standby) mode (the sleep/standby indicator
turns on) immediately after Power-on self-test (POST).
Solution:
1. Make sure that:
v
The battery is charged.
v
The operating temperature is within the acceptable range. See
“Specifications” on page 70.
2. If these items are correct, have the computer serviced.
Problem:
The
critical low-battery error
message is displayed, and the computer
immediately turns off.
Solution:
The battery power is getting low.
Do either of the following:
v
Connect the AC adapter to the computer and plug it into an electrical
outlet.
v
Replace the battery with a fully charged one.
Problem:
When you take action to return from sleep (standby) mode, the computer
display remains blank.
Solution:
1. Check whether an external monitor was turned off while the computer
was in sleep (standby) mode.
2. Do either of the following:
v
Turn on the external monitor to display the image on it.
v
Press Fn+F7 to bring up the image on the computer screen.
Note: If you use the Fn+F7 key combination to apply a presentation
scheme, press Fn+F7 at least three times in three seconds.
3. If the problem persists, do the Solution in the following Problem.
Chapter 3. Solving computer problems
25