Dell Precision T3400 (Late 2007) - Manual (Page 257)

Adding and Replacing Parts
257
5 Slide the power supply toward the front of the computer by approximately
one inch.
6 Lift the power supply out of the computer.
Replacing the Power Supply
1 Slide the power supply into place.
2 Replace the four screws that secure the power supply to the back of the
computer chassis.
3 Reconnect the DC power cables.
1 power supply screws (4)
1