Apple PowerBook (3400 series) - Manual (Page 173)

21 While continuing to hold the keyboard in place, replace the three screws on the bottom
of the Macintosh PowerBook.
Not too tight: Take care not to overtighten the screws. Tighten them only until
they are snug (when you feel resistance to your turning motion). It’s better to
leave them a bit loose than to make the screws too tight.
22 Turn over the computer and prepare to use it.
Replace the battery and reconnect the power adapter and any cables you
removed before installing the RAM expansion card.
1 Gently but firmly squeeze the
keyboard and the other parts of
the computer together. 2 While squeezing the parts together,
reinstall the three screws into the bottom
of the computer.
173 Installing a Macintosh PowerBook RAM Expansion Card