Dell OptiPlex 740 - Manual (Page 207)

System Board Components
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 2 floppy drive 3 power supply
4 chassis intrusion switch (optional) 5 system board 6 heat sink assembly
7 hard drive
1 speaker connector
(INT_SPKR) 2 processor socket (CPU) 3 memory module connectors
(DIMM_1, DIMM_2, DIMM_3,
DIMM_4)
4 power connector
(PW_12V_A1) 5 SATA drive connectors
(SATA2, SATA3) 6 SATA drive connectors (SATA0,
SATA1)
7 front-panel connector 8 power connector 9 intrusion switch connector