Question PSU voltages slightly low ?

Feb 12, 2021
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I have had some PSU issues so I measured the voltages of the motherboard and CPU connectors, most are about 0.1V off the correct voltage. The voltage of the 12V CPU connectors is 11.79V and the 3.3V connections on the motherboard connector are at 3.24V. The multimeter say that it has a reading within 0.5% of the reading (0.06V for 12V and 0.0165V for 3.3V) which [?]
 
Feb 12, 2021
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Make and model of your PSU and it's age? You will also need to factor in that age will cause the capacitors or VRM's to degrade and deliver less power to the components.
I have Corsair CX550, it's about 1 and a half years old.
 
Feb 12, 2021
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That's not how it works. The .5% is the error of the meter. This .5% is error can be pretty much neglected for practical purposes. The spec is 11.4-12.6V. That is where you want your 12V rail(s) to read.
Oh I understand, thank you for clearing that up.
 
Feb 12, 2021
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That's not how it works. The .5% is the error of the meter. This .5% is error can be pretty much neglected for practical purposes. The spec is 11.4-12.6V. That is where you want your 12V rail(s) to read.
If output voltages are alright could anything else be wrong the PSU? My computer won't start at all with no fan spin so I'm lead to believe that it is a PSU issue.
 
Even if the voltages are in spec, PSUs can still be defective. Do you have another PSU to test out to make sure it's a PSU problem? No fan spinning is an indication of a PSU problem, but the worst that can happen is that you can claim the warranty to Corsair and get a new one.
 
Feb 12, 2021
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Even if the voltages are in spec, PSUs can still be defective. Do you have another PSU to test out to make sure it's a PSU problem? No fan spinning is an indication of a PSU problem, but the worst that can happen is that you can claim the warranty to Corsair and get a new one.
I don't have another PSU on hand, I will try to find someone to borrow one from.
 
I have had some PSU issues so I measured the voltages of the motherboard and CPU connectors, most are about 0.1V off the correct voltage. The voltage of the 12V CPU connectors is 11.79V and the 3.3V connections on the motherboard connector are at 3.24V. The multimeter say that it has a reading within 0.5% of the reading (0.06V for 12V and 0.0165V for 3.3V) which [?]
Instead of analyzing your testing methodology, let's roll back to troubleshooting your actual problem.

What are the "PSU issues" you're experiencing and what makes them "PSU issues"?
 
Ok. Let me rephrase and you tell me if I have this correct.

Paper clip in PSU makes PSU turn on.

Turning on via the motherboard doesn't always work. But it does if you let the system sit for a while.

The heavy load thing is confusing. Are you saying it shuts down and doesn't turn back on when you perform heavy loads?

What motherboard, GPU, CPU, etc. are we using here?

And it's only a 1.5 year old PSU, so this is the CX550 with the black letters on the gray label, correct?
 
Feb 12, 2021
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Instead of analyzing your testing methodology, let's roll back to troubleshooting your actual problem.

What are the "PSU issues" you're experiencing and what makes them "PSU issues"?
My computer has no fan spin and will not post when I press the power button, I have tried breadboarding and this does not solve the problem, the orange motherboard power indicator is on as usual when the PSU is switched off from the back but plugged in. This has happened multiple times, when it happens, it usually takes a few days and then it starts working perfectly normally again for a while and the cycle repeats, this has happened 6 times.

Sometimes the time is not correct when it boots again so I have changed the CMOS battery, which has not fixed the problem. There is no fan spin at all not even in the PSU but there is fan spin in the PSU when I test it with a paper clip in the motherboard power connector.

I am not 100% sure but when I strain it with heavier loads like gaming, it seems to stop working although it might be a coincidence since I have only noticed this recently.

Whenever this happens I had turned off the computer the night before and it does not turn on in the morning, it has not crashed whilst it has been running or stopped working after short amounts of time of being shut down either.
 
Feb 12, 2021
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Ok. Let me rephrase and you tell me if I have this correct.

Paper clip in PSU makes PSU turn on.

Turning on via the motherboard doesn't always work. But it does if you let the system sit for a while.

The heavy load thing is confusing. Are you saying it shuts down and doesn't turn back on when you perform heavy loads?

What motherboard, GPU, CPU, etc. are we using here?

And it's only a 1.5 year old PSU, so this is the CX550 with the black letters on the gray label, correct?
Yes it is the one with black writing on the grey sticker, I'm not sure about the heavy loads as I game fairly often so it might be a coincidence.

CPU: AMD Ryzen 5 2600
Mobo: ROG Strix X470-F Gaming
GPU: msi GeForce GTX 1050 Ti
RAM: Corsair Vengeance LPX 8GB (x2)
SSD: WD Blue 250GB SSD
HDD: Seagate Barracuda 2TB HDD
 
Yes it is the one with black writing on the grey sticker, I'm not sure about the heavy loads as I game fairly often so it might be a coincidence.

CPU: AMD Ryzen 5 2600
Mobo: ROG Strix X470-F Gaming
GPU: msi GeForce GTX 1050 Ti
RAM: Corsair Vengeance LPX 8GB (x2)
SSD: WD Blue 250GB SSD
HDD: Seagate Barracuda 2TB HDD
Ok. Also, you said:

the orange motherboard power indicator is on as usual when the PSU is switched off from the back but plugged in.
If the PSU is "off" from the back, the orange LED should not be on. Or, rather, it should eventually turn off as the capacitors in the PSU discharge.

Not saying this couldn't be a PSU issue, but it could equally or more so be a motherboard issue.
 
Feb 12, 2021
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Ok. Also, you said:



If the PSU is "off" from the back, the orange LED should not be on. Or, rather, it should eventually turn off as the capacitors in the PSU discharge.

Not saying this couldn't be a PSU issue, but it could equally or more so be a motherboard issue.
Sorry, this was a mistake, the orange LED stays on when the switch on the back of the PSU is on it is off when the switch is off as it should be.
 

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