I’m really hoping it was a power supply issue as that can be replaced easily.
I actually do not have a pNode device myself so my diagnosis will be a slight shot in the dark. Is there any type of power indicator LED on the power supply itself? If there is you can try plugging in the power supply without plugging in the pNode to it and see if the power indicator lights up.
Did you notice any smoke or does anything smell burned? With everything unplugged try smelling both the power supply and the pNode separately. If you do there could have been a short in the motherboard PCB or a burned-out component.
In the event, it was just the fan that malfunctioned you should still be able to get the pNode to boot. Although not recommended to run it for a long time without the fan for testing purposes you can try.
If the board had a popped capacitor this is replaceable by someone who knows what they are doing and has skills/equipment to resolder a new cap.