[SOLVED] PSU only turns on when left off for a few hours, otherwise I just get fan spin and a clicking noise

Jan 21, 2019
2
0
10
0
I have a Cooler Master V750S that only turns on after left off for a few (~10-12 at most) hours. If I try to turn it on too soon, I've tried at 3-4 hours after turning it off, I get some fan spin and a click, then nothing. From what I've found online, it might be a short? After being started however, the power supply performs perfectly normally; there's no random shutting off or anything. I know it's a problem with the power supply because it exhibits the same behaviour when plugged into my personal rig and when I try doing the paper clip test.

I got it for free recently when an office was upgrading their PCs, so I'm just hoping that this can be fixed as it's a shame to see a pretty decent power supply go to waste. Unfortunately the warranty on it has run out as it was sold in a system instead of individually, otherwise it would still be covered.

It's usage in the office was that the PC would be turned on at the start of the day and used until the end of the day, so the problem could have existed before their upgrade and never have been noticed.

Here are the parts in the PC if it helps:
Mobo: GA-B85M-D3H
CPU: Intel i7 4790
RAM: G.SKILL Ares 2 x 4GB DDR3
GPU: GeForce GTX 750Ti
PSU: Cooler Master V750S (as aforementioned)
Storage: Toshiba 1TB HDD

Thank you for taking time out of your day to read this.
 
The problem might be due to the primary capacitor failing. If so, capacitor replacement is not too difficult.

However, the PSU should be checked out by someone with experience/expertise just to verify what component(s) is/are failing and suitable replacements made (if possible).

But this diagnostic and remedial work could be expensive. It might be cheaper to just buy another (new) PSU.

CAUTION! PSU's contain high voltage inside. This voltage might remain even after switching off and disconnecting from power source. So there is the possibility of getting an electric shock if one is not very careful when working inside the PSU!! Therefore any work inside the PSU should only be carried out by competent personnel who know what they are doing.

EDIT: Could try another known working PSU in the computer as a test. If this other PSU runs the computer without issue, then the original PSU must be faulty. If there are persistent problems with the test PSU installed as well, then the motherboard may be faulty.
 
The problem might be due to the primary capacitor failing. If so, capacitor replacement is not too difficult.

However, the PSU should be checked out by someone with experience/expertise just to verify what component(s) is/are failing and suitable replacements made (if possible).

But this diagnostic and remedial work could be expensive. It might be cheaper to just buy another (new) PSU.

CAUTION! PSU's contain high voltage inside. This voltage might remain even after switching off and disconnecting from power source. So there is the possibility of getting an electric shock if one is not very careful when working inside the PSU!! Therefore any work inside the PSU should only be carried out by competent personnel who know what they are doing.

EDIT: Could try another known working PSU in the computer as a test. If this other PSU runs the computer without issue, then the original PSU must be faulty. If there are persistent problems with the test PSU installed as well, then the motherboard may be faulty.
 
I had a similar problem but it wasn't the PSU at all. This was on an ASUS motherboard and redoing the heat conductive paste on the chip set heat sink corrected it. It's worth a try if that mobo's chip set heat sink is removable.

The heat builds up all day while it's running and when you turn it off it takes some time to cool off when the fans aren't running. One way to test if this is the problem is to remove the side panel of the case and see how long it has to sit before it will start again. If it is a shorter amount of time than before it's likely the cause.
 
Jan 21, 2019
2
0
10
0
Thank you both very much for answering. I'm almost absolutely certain the problem is with the power supply, so I suppose there is no easy solution and the only way to fix it would be to get someone with more experience to diagnose the issue within the PSU. I don't think I'll try and fix it though because I was only hoping to upgrade my own PC with it (I have a Cooler Master 550W OEM PSU in there right now) and it's not a necessity. Besides, the PSU can still be used perfectly normally once it's started, so I can use the PC/PSU normally if I have any 24/7 applications. In fact, it's been on the entire day and still on now running an idle game just because.

Thanks again for answering, and I guess I'll just leave this open as the problem isn't really solved. Maybe someone will have a miraculous amazing fix with just one click of a button, but until then I'll just deal with it I suppose.
 

ASK THE COMMUNITY