Newly built pc motherboard get no power

Tharuka

Honorable
Jan 11, 2014
23
0
10,520
hi all
i built a new pc last nyt but motherboard doesnt start.
CPU is AMD A4
MOBO GIGABYTE F2A55-DS3
PSU Coolermaster Thunder 600w
 

Tharuka

Honorable
Jan 11, 2014
23
0
10,520
please help me. im wondering about the 20 th pin of the main power connecter in mobo user manual its say -5V but psu 20 th pin is blank.(i mean there is no wire)
 

Tharuka

Honorable
Jan 11, 2014
23
0
10,520
AMD A4 4000 dual core
GIGABYTE GA-F2A55-DS3 Sata 2 USB 2 HDMI RAID ATX
patriot signature 4GB single DDR3 -1600
WD 3.5 green iTB
PIONEER SATA OEM DVD rw
Coolermaster THUNDER 600W