Dell OptiPlex 740 User Manual page 207

CAUTION: Before you begin any of the procedures in this section, follow the safety instructions located in the Product Information Guide.
CAUTION: To avoid electrical shock, always unplug your computer from the electrical outlet before removing the computer cover.
NOTICE: Be careful when opening the computer cover to ensure that you do not accidentally disconnect cables from the system board.
1 optical drive
4 chassis intrusion switch (optional)
7 hard drive
System Board Components
1 speaker connector 2 processor socket (CPU)
(INT_SPKR)
4 power connector 5 SATA drive connectors
(PW_12V_A1) (SATA2, SATA3)
7 front-panel connector 8 power connector
2 floppy drive 3 power supply
5 system board 6 heat sink assembly
3 memory module connectors
(DIMM_1, DIMM_2, DIMM_3,
DIMM_4)
6 SATA drive connectors (SATA0,
SATA1)
9 intrusion switch connector