Question PC only boots when nothing extra is plugged into the PSU

[Gaelican]

In short i have a pc with parts that are known good other than the PSU and mobo, which i dont know how well they work. Basically right now i can only boot if only the cpu and motherboard power are plugged in. If i try to plug in a GPU or a storage then the fans will spin for a second then stop. Im thinking this is the PSUs fault but i wanted to see if theres anything i can do to fix this, or can it be the mobo causing this issue?

Also just to add, this pc was working when i last tried (2 years ago) with the same components except fhe psu, also the psu is 650w which should be easily enough

 

[rgd1101]

make and model of the psu?
just the wattage is not enough need to know if the psu is a good model

 

[Ralston18]

If the computer is booting then there is at least a boot drive and memory.

Even if PSU is 650 watts that is no guarantee it is fully operational. Make, model, age, condition also matter.

One thing you can do is test the PSU voltages.

Reference:

https://www.lifewire.com/how-to-manually-test-a-power-supply-with-a-multimeter-2626158

Not an "under load" test but may reveal some problem within the PSU.

 

[Gaelican]

PSU is corsair CS650M. I guess i misused the word boot, i meant that i could get into the bios. I will try checking the voltages as soon as i can, but i know the voltages in the cpu and motherboard cable are fine

 

[Gaelican]

make and model of the psu?
just the wattage is not enough need to know if the psu is a good model

If the computer is booting then there is at least a boot drive and memory.

Even if PSU is 650 watts that is no guarantee it is fully operational. Make, model, age, condition also matter.

One thing you can do is test the PSU voltages.

Reference:

https://www.lifewire.com/how-to-manually-test-a-power-supply-with-a-multimeter-2626158

Not an "under load" test but may reveal some problem within the PSU.

Its corsair CS650M