PC won't boot or POST -- might be the PSU?

My PSU is a Corsair HX850 that I've been using for around 4.5 years.

 

Unfortunately this morning I woke up to my PC turned off (I almost always leave it on overnight) and making a clicking sound.

 

The fan on my CPU cooler seems to power on fine, but nothing else (no other fans or other components) does. When I first power it on, the CPU cooler fan revvs up fine, but then I start hearing a clicking sound every few seconds. At first I thought it might be my HDD, but I unplugged that and still no go. Googling around made me think the clicking is coming from the PSU.

 

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There's a video of my PC. Also noticeable is the red LED flickers a bit with each click. It's hard to tell if the CPU cooler fan is slowing down at all, though. In the video I didn't have a mobo speaker plugged in, but I have since put one in and still no post. There is a very faint beep, I think, but post is supposed to be pretty loud I thought.

 

Anyone have a clue?

My first suspicion would be the PSU, yes.

Any ideas on how I could help narrow it down to the PSU alone? That was what I was assuming for awhile as well, but after posting this issue on another forum someone said they had a similar issue and it ended up being the mobo. So who knows.

Any ideas on how I could help narrow it down to the PSU alone? That was what I was assuming for awhile as well, but after posting this issue on another forum someone said they had a similar issue and it ended up being the mobo. So who knows.

 

By your description and watching the video, it does appear to be a power issue more than anything else. Do you notice the hard drives powering down along with the rest of the system?

 

You could also try some basic diagnostics to see if it fixes the issue, even temporarily:

 

• Reseat the RAM sticks
  
• Unplug the computer, hold down the power button for 10 seconds, plug it back in and power it on
  
• Reset the BIOS jumper
  
• Inspect the motherboard for any scorched components, blown capacitors or anything else weird
  
• Try swapping components with another working system.
  

 

Sometimes you have to be careful with the last one as one bad component could ruin perfectly working ones. I don't see any issue with getting another power supply to test it with. I just wouldn't put the potentially broken power supply in a working system.

Small update: I don't think it's the PSU.

 

I did the paperclip test posted at the top of these forums, but instead of a system fan (wasn't really sure how to connect a 3pin system fan directly to the psu), I used an old molex harddrive. Harddrive seemed to power up fine and there was no clicking. The fan on the PSU itself only started up briefly before stopping, but I think the HX850 is a fanless model.

 

Edit-

I forgot to say that prior to removing the PSU, it did sound like my harddrives were stopping briefly before starting up again with each of the clicks.

Using a molex hard drive only "tests" two of the 3 rails on the PSU - 12V and 5v. And those would actually be on different rails than the rest of the system. Furthermore, HDDs aren't as sensitive to voltage fluctuations and don't even see the Power Good signal. I would not take your test as a definitive answer that "it's not the PSU".

 

Really, a more definitive test is a dedicated PSU tester. Or put in a "known good" PSU.

Tried another PSU test and so far it looks good. I connected it to the old mobo I used until last year, along with a single stick of ram+cpu fan. Powered up fine, no clicking, and a single beep for post (which for my mobo is good).

 

On to testing each part, QQ.

We're up and running.

 

I ended up unplugging almost everything from the mobo, and still had the same issue. I removed the mobo from the case and only had a ram stick plugged in. It gave me 5 beeps for post. I thought 5 beeps meant something to do with the CPU, but I found a youtube video that lead me to finding it was the ram. I had my ram stick plugged into the 2nd ram slot so I put it in the first slot. I then got a 1 beep post. Woot!

 

I unplugged my psu from the mobo, put the mobo back in my case and plugged the PSU back in. Started it up, but I was back to square one. Once more I took everything out, did the same thing as before, and again one beep for post.

 

This time I left the PSU plugged in and put the mobo back in the case. It continued giving me one beep. So I just slowly put parts back in while testing power up after each part. Finally got everything plugged back up and here we are.

 

In the end, I'm not really sure what the issue was.