Power supply killer?

afseth · January 20

Hi, I recently bought a few used motherboard/CPU combos from a seller. The first combo worked perfectly at first. However when i tried the second one (note: with the same PSU), the motherboard LEDs turned on, but when i pressed the power button i only heard a click from the power supply and the system didnt start.

After that, the first motherboard/CPU combo also stopped booting because of the exact same problem with the power supply. I ended up replacing the power supply, but when i tested the second motherboard/CPU combo again.. You guessed it, same issue. Which has ultimately led me to think its the second motherboard/CPU combo..? Help.

Toryze · January 20

Have you tested it again and again to see if the power supply is completely dead now? My guess is that there's a short on the second motherboard, which could've led to some component within the PSU dying. This is only my guess, and you'll have to verify the issue on your end.

Eigenvektor · January 21

If the power supply makes an audible click, that's usually some kind of relay. Usually a protective circuit that kicks in to avoid damage. The actual culprit is most likely a short on the motherboard's side and the PSU turned itself off to avoid damage to itself.

Had the same happen when an old GPU died. PSU clicked and PC turned off. Had to wait ~10 minutes before I could turn the computer back on. The PSU was fine, the GPU unfortunately was not. It dying is likely what triggered the PSU to shut down.

Potatoes__ · January 21

I'd also carefully check both sides of the mobo to make sure that nothing is shorted out there, especially around the PSU connectors. Like a stray screw or metal shaving or whatever. And obviously make sure that the back of the board is not touching anything conductive when you are powering it.

seon123 · January 21

11 hours ago, Eigenvektor said:

Usually a protective circuit that kicks in to avoid damage.

It's typically the NTC bypass relay, which clicks every time you turn your PC on and off, just like old TVs. If a PSU's protections trigger, and it shuts off, it'll then of course switch off the relay.

18 hours ago, afseth said:

Hi, I recently bought a few used motherboard/CPU combos from a seller. The first combo worked perfectly at first. However when i tried the second one (note: with the same PSU), the motherboard LEDs turned on, but when i pressed the power button i only heard a click from the power supply and the system didnt start.

After that, the first motherboard/CPU combo also stopped booting because of the exact same problem with the power supply. I ended up replacing the power supply, but when i tested the second motherboard/CPU combo again.. You guessed it, same issue. Which has ultimately led me to think its the second motherboard/CPU combo..? Help.

What model PSUs, motherboards, and CPUs? If you have a multimeter and a paper clip, you can check if the PSUs output any voltage, 5Vsb when turned off, and the normal voltages when turned on.