A few days ago, my desktop PC just stopped turning on. Pressing the power switch elicits no response altogether.

This is the sum total of the troubleshooting steps I've done:

  • Super-newbily switched power supply I/O switch off and on a number of times as recommended in the PSU manual.
  • Also very newbily watched a YouTube video about the power supply "paperclip test" and verified that yes, I can jumpstart it with a paperclip.
  • Exhausted my entire knowledge of electronics by unplugging all of my PC case's power switch/reset switch/case LED plugs from the motherboard and then tried to test if the case power switch is busted by closing the motherboard power switch circuit by touching a flat-head screwdriver to the two switch pins. Absolutely nothing happened. No PSU startup.

I do not own any testing tools like a multimeter or know much about electronics. I also value my time and would rather not spend hours diagnosing the problem if the balance of probabilities says "replace component X".

Should I just go ahead and buy a new PSU? Or are there some simple tests I can do using what I have around home that would give a clearer picture of whether it's the mobo or the power supply unit?

(FWIW, it's a 350W DiabloTek PSDA350 DA Series 350-Watt ATX Power Supply which I got for like $14.99 off of Amazon.ca one fine day. Always been a noisy bugger. Have a vague recollection of assuring myself it had enough juice to run my simple hardware when I bought it two years ago.)

  • Can you use another PSU? Can you test the PSU on the other system? – Tom Apr 17 '16 at 5:12
  • If changing PSU won't solve the problem, then motherboard is broken. – Alexiy Apr 17 '16 at 6:11
  • @Tom, I'm afraid not easily. I only have the one PC, and only the one power supply in it... – user1911388 Apr 17 '16 at 17:32
  • In my opinion your PSU is broken 80 percents. – Tom Apr 18 '16 at 5:00
  • Ordered a new one last night - I want a new nice quiet one anyway. If that don't fix it, I'll have to get serious :) By the way, @Tom, I assume this means inability to short-circuit the motherboard power switch doesn't necessarily indicate a motherboard problem? – user1911388 Apr 18 '16 at 16:01

It was the power supply. Replaced the two-year old 350W DiabloTek unit with a brand new fanless 460W Sea Sonic unit and it's humming away. And by humming, I mean humming barely audibly!

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