Dell Precision T3400 (Late 2007) - Manual (Page 241)

Adding and Replacing Parts
241
3 If you already have a speaker installed, remove the old speaker:
a Disconnect the speaker cable from the speaker connector on the
system board.
b Simultaneously grasp the bottom of the speaker with your index finger
and press down on the latch release tab with your thumb.
c Slide the speaker up and out of the three speaker slots.
1 speaker (optional) 2 latch release tab
3 speaker slots (3) 4 speaker cable
5 speaker connector on system
board
2 1
3
4
5