Dell Precision T3400 (Late 2007) - Manual (Page 208)

208
Adding and Replacing Parts
8 Connect a power cable to the hard drive and to the power supply.
9 Connect the serial ATA cable to the back of the drive and to the SATA
connector on the system board.
1 sliding-plate lever 2 hard-drive holder with hard drive
The optional third hard drive is
located in the lower 5.25-inch
drive bay for desktop computers.
1
2