Apple PowerBook (3400 series) - Manual (Page 171)

17 Lower the keyboard into place.
If part of the keyboard doesn’t lie flat within the enclosure, gently press that
area down with your hand.
18 Remove the cloth from the display.
19 Slightly close the display so it is at a 90-degree angle to the computer.
90
°
171 Installing a Macintosh PowerBook RAM Expansion Card