How do I know that my power supply is the fault and not my motherboard

I have a ps4 pro that i bought used for 40 bucks knowing it had a issue were you was unable to power it on. ive tested to plug it in and it wont turn on ive tried booting in to safe mode but still no light no beep etc. I also tried to put my ps4 slim hdd in just to see if i would at least get it to boot but still nothing. so im not sure if its a motherboard fault and not a psu. when i plug in the ps4 i hear a crackle but thats it and im pretty sure thats normal. Correct me if im wrong, but i dont hear it all the time when trying to plug it in so im not sure. Ive tried testing it with a multi meter but its hard cause my testing pins are short and dont reach in to the metalconnector in the power supply. is there a way for me to test out the powersupply to actually know that thats the cause. I dont want to put in 70 dollars on a part just for it not be the problem.

Thanks and sorry for my broken English im Swedish there for im not so good

Best of regards Joseph