Apple PowerBook (3400 series) - Manual (Page 168)

15 Lay the card flat, then gently press the card into the socket.
You need to exert some pressure to insert the card’s connector into the socket.
It’s all right to wiggle the card to move it or to insert one side and then the
other, but be very careful not to bend or bow the card.
Make sure the keyboard cables are still properly connected.
Check to see that the RAM card is properly seated
in its socket. Press down firmly on these two
areas and be sure that the RAM card
has clicked into place.
Check to see if either of these keyboard cables has
been pulled out of its socket on the logic board.
168 Appendix C