Power Supply or Motherboard?

[Ratman6161]

I have something really strange going on that I suspect must be the power supply.

Old system: Asrock z68 Pro3 motherboard with i7-2600L.

New system: Asrock AB350 Pro 4 AM4 motherboard with R51600. Other than the motherboard about the only other component thats new is the RAM since the old system was DDR3 and the new is DDR4. Also added a Samsung 960 EVO NVMe drive. Same power supply as the old system. Same Corsair AIO water cooler and all the fans.

Here is the issue: When I tell Windows 10 to shut down, it does so normally and everything appears normal except that the fans are still running at very low speed as is the pump on the Corsair cooler. Most of the fans are conn3ected directly to the motherboard, but one of the case fans is not. that one is a 12 volt connector directly to the power supply. It keeps running (very slowly) too. Sinc that one isnt connected to the motherboard, my guess is it must be something to do with the power supply???

Any recommendations on things to check other than just replace the PS?

 

[Torn Mind]

Could be software related.

If shutdown works fine in a Linux OS, for example, then something is up with the Windows install. You can try a LiveCD first. Then maybe install Linux on a storage drive.

 

[Ratman6161]

Could be software related.

If shutdown works fine in a Linux OS, for example, then something is up with the Windows install. You can try a LiveCD first. Then maybe install Linux on a storage drive.

I will try that. One additional factor however that I forgot to mention. Because the fans still run after shutdown, after the Windows shutdown completes, I've been turning off the switch on the power supply - figuring that the very small amount of juice going to the pump motor cant be good for it. Of course once I turn off the switch all power is removed and the fans stop. I generally use this system Thursday through Sunday so once I turn off that power switch on Sunday night, it will stay that way for several days. As soon as I turn the power supply switch back on, the fans spin up again.

 

[PianoMan]

Have you tried manually starting the power supply and checking the voltages?

I'd initially think PSU, but you mention that ALL fans run (even those connected to the motherboard). Not familiar with that cutting edge AMD chipset, but if the mobo allows voltages to still be applied - you should rule that out, and manually starting the PSU will do that easily.

To Torn's point - I am assuming this is a fresh build? So just a bare install of Windows?

 

[Ratman6161]

Have you tried manually starting the power supply and checking the voltages?

I'd initially think PSU, but you mention that ALL fans run (even those connected to the motherboard). Not familiar with that cutting edge AMD chipset, but if the mobo allows voltages to still be applied - you should rule that out, and manually starting the PSU will do that easily.

To Torn's point - I am assuming this is a fresh build? So just a bare install of Windows?

Relatively fresh build but no, not just windows - full set up. I've had it up and running since May with no other problems. I just noticed this issue a few weeks ago but It may have actually been doing this for a while and I just never noticed.

One thing I did try since my last comment was to disconnect all the front panel connectors from the case to the motherboard, including the power and reset buttons and also disconnect the fans that were connected to the motherboard. So I was in a configuration where the only fans connected to power where the ones connected directly to the PS. Those fans connected to the PS still spun up when I turned on the switch to the power supply.

From this I've pretty much concluded I need a new power supply. Cant even remember the brand of the one I have in there but I think it was an inexpensive one to begin with...and its 6 years old, so its probably about time.

 

[PianoMan]

Ok - then there u have it, though I admit I have never seen this specific type of sign of a PSU going bad. Learning point here! Good luck!


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[Ratman6161]

Ok - then there u have it, though I admit I have never seen this specific type of sign of a PSU going bad. Learning point here! Good luck!


Sent from my iPhone using Tapatalk Pro

New to me too. But over the weekend I said the heck with it and put in a new power supply. Problem solved. Nothing changed but the power supply so I'm assuming that was the issue. That old PS was 6.5 years old and I didn't remember till I removed it that it was an el-cheapo 600 watt, so I guess its somewhat surprising that it lasted this long. Replaced it with this one of these:
EVGA 650 GQ, 80+ GOLD 650W
https://smile.amazon.com/gp/product/B017HA3SQ8/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

Not exactly a high end unit but I've had good like with the 750 watt version that I've used in other systems. My system only pulls about 300 watts when maxed out, so I figured a 650 was plenty. Anyway, as I said, problem solved.

 

[PianoMan]

Good to hear! Tks for the closeout!


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