Friends computer wont turn on

[Toobaked]

Hello friends,
Today I helped a friend change the PSU on his computer. He had a spektra PSU and changed to the EVGA 750 Bronze 80 plus. His motherboard is the B85-G43 an I5 4460 CPU and an ASUS strix 950 GPU. The problem is that after changing the PSU the computer fans would turn on for less than a second and didn't turn on. I checked the connections of MOBO cable and CPU cable but they were correctly connected. All cables were fine and connections were ok. We were wondering if the problem came from the MOBO or the PSU. Maybe the PSU was defected or while changing the MOBO there was something that messed it up. Please Help
Thank you

 

[Valkyrieneos]

Similar thing happened to me a while ago when I plugged a usb connected led strip intended for tv use into my pc case which either had a diffrent voltage or made the power supply limit get overtaken by the demands. Unplug all usb devices and try start it including mouse and keyboard. Also try using a diffrent hdmi cable or switching the cable ends around . Try putting the monitor turned on before you try power the pc

 

[Toobaked]

We changed back to the old PSU and computer worked fine. I believe that problem is in the new PSU

 

[jsmithepa]

Obvious things to check: inspect connectors' pins, nothing unusual? Connectors sit flushed with Mobo's headers? PSU has 120/240 selector switch?