Dell OptiPlex 740 - Manual (Page 177)

System Board Components
1 drive-release latch 2 optical drive 3 power supply
4 chassis intrusion switch (optional) 5 hard drive 6 card slots (2)
7 system board 8 heat sink assembly
1 fan connector (FAN_CPU) 2 processor socket
(CPU) 3 power connector
(PW_12V_A1)
4 memory module connectors
(DIMM_1, DIMM_2, DIMM_3,
DIMM_4) 5 power connector
(POWER1) 6 SATA drive connectors
(SATA0, SATA1)
7 front-panel connector
(FRONTPANEL) 8 fan connector
(FAN_HDD) 9 intrusion switch
connector (INTRUDER)
10 CMOS reset jumper (RTCRST) 11 battery socket
(BATTERY)
12 internal USB (USB1)
13 standby (AUX_PWR_LED) 14 PCI Express x16
connector (SLOT1)
15 PCI connector (SLOT2)
16 password jumper (PSWD) 17 serial connector
(PS2/SER2)
18 slim floppy drive
connector (DSKT)