Have you tried all power connectors ?
Are you sure your power supply is ok ?
Check the fuse, it's probably on the same position as the Bitburner boards:
http://www.burninmining.com/news/ (first picture)
Yes, both power connectors is not working. With watt meter it show only psu power draw about 6 watt.
How do I check if the fuse is blown with multimeter? I got 0 knowledge about this kind of stuff but I got multimeter for my Bitfury Oct Kit.