Apple Macintosh PowerBook 1400 - Manual (Page 27)

m You can also put your computer to sleep by closing the display.
When the computer is in sleep, a small green light flashes in the upper-right
corner of the display.
After closing the display, be sure to check that the sleep light is blinking (at
the top-right edge of the display). If you don’t see the blinking light, open the
display and use the Control Strip or the Special menu to put the computer in
sleep.
Note: You may notice that the computer sleeps when the display is not closed
completely. Sleep is initiated by a magnet-controlled switch that may engage
before the display is flush with the lower part of the computer’s case. Also,
you may need to open the display to an angle of about 45 degrees to
disengage the sleep switch. (Then press any key, except Caps Lock or the
trackpad button, to wake the computer.)
For information on other ways of putting the computer to sleep, see the
“Batteries & Power” topic of Mac OS Guide, available in the
Guide (h) menu.
Sleep indicator
27 Getting Started