[SOLVED] Computer Not Turning On With A Different Working PSU! How To Fix it?

[Joezhang07]

I have 2 Non-Brand SFF which are Pre Builts with normal consumer non-proprietary parts but I have noticed the PSU has no Power Switch and when I plug a PSU with an on-off switch both computers refuse to turn on. It works perfectly on the Non-Switched PSU and my Switched PSU works fine on other desktops. This is completely mind-boggling and have been pulling my hair out.

Computer 1:
CPU:i5 3470
RAM: 12GB DDR3
MB: Gigabyte GA-B75-D3H
PSU: Power Man 300 w

Computer 1:
CPU:i5 4590
RAM: 8GB DDR3
MB: Gigabyte GA-B75-D3H
PSU: Power Man 300 w 80 Plus Gold

 

[Lutfij]

Is this your motherboard?
https://www.gigabyte.com/Motherboard/GA-B75M-D3H-rev-10#ov
I can't find a GA-B75-D3H.

Can you source a reliably built PSU, from your friend or neighbor who owns a PSU that has at least 450W of power for the entire system? If so, use that to power the system's up(individually) and see if they function.

It's possible the unit with the rocker switch is faulty/failing or that the rocker is in the off state permanently. Also, how do you have the rams loaded out on both system's?