Can psu pass self test but still be faulty?

[Mcnumpty]

Brand new x570 build working fine for a week but today dead as a dodo

 

Disconnected all psu cables pressed self test and green light and psu fan spins

 

Reconnect system totally dead not a single sign of life

 

But if I only connect 24 pin and 8 pin cables from psu to motherboard

 

And yes I know the next bit isn't how you self test psu

 

But if I press self test I get 1/2 a second of pc trying to start leds light up etc

 

This kind of suggests that though the psu passes self test the 12v rail or something may not actually be fully functional

 

So is the self test very basic?

 

Ie it only checks power goes into psu and fires up the fan? But doesn't guarantee a fully functional psu?

 

By the way it's a 10 year old ax860i the only not new part in the pc though in 10 years its never let me down yet

 

And no sadly I don't have a spare psu to double check with.

 

Sorry for any errors but the writing in this forum comes up tiny on my phone but zooming means can't see all the page width at same time

[Mcnumpty]

So to update

 

I jump started psu.. Using 4th and 5th pin down.. That's with the latching clip facing right which should be correct I think guess having all black psu cables can be a nuisance sometimes

 

And connected a pump which I guess is around 10w

 

The pump didn't run or at least I couldn't feel any vibration from it putting my finger on it

 

So leaning towards yes the psu can pass self test yet still be faulty

 

Unless some one can definitely tell me otherwise before I go shell out £150 or so for a new psu tomorrow