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Question

My fans in my desktop computer never stop running

Jan 23, 2015 5:38AM PST

Well my computer was custom built but not by me and i just have no clue how to fix my problem. when i shutdown my computer it makes all the normal shutdown noises and then my fans get a little quiet like they are about to turn off then about 3 seconds later they go full speed and just never stops. i have to turn the whole power supply off to get them to stop. the computer appears to be shutdown but its loud cause of the fans... and all fans are on the cpu fan the side fans and the power supply fan. any ideas why this happened or how i can fix it.

Discussion is locked

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Clarification Request
Do you have a DVM or access to one?
Jan 23, 2015 6:37AM PST

It sounds like something trying to restart. These fans should run on 12vdc. Generally motors use 12v and logic circuits use 5v. It would be good to know if any other voltages can be read at the PS connector on the motherboard.

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what?
Jan 23, 2015 6:53AM PST

what is dvm?

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It stands for Digital Volt Meter
Jan 23, 2015 8:59AM PST

but most are called "multimeters" as they can read ohms and amperes. What I was looking for is to see if you can measure voltages. It could sound as if your PC was completely powered but no rebooting or hanging on reboot. You said it makes all of the usual shutdown noises. One that's usually easy to hear is the clicking when hard drive heads park. That will be the last thing you'd notice when the PS shuts down and should confirm that shutdown actually took place.

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ahh yea i dont have one of those.
Jan 23, 2015 9:08AM PST

and yes i can hear my hard drive make that clicky noise and right after that sound is about when my fans start going full speed

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Answer
sounds like fans hooked
Jan 23, 2015 5:48AM PST

directly to the power supply instead of the motherboard. If they are hooked to the motherboard and keep running, then some other problem, either motherboard, or processor (someone bent a pin maybe?)

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what do you think i should do?
Jan 23, 2015 6:55AM PST

bent a pin? how do i fix that? and yea i think everything is hooked into the motherboard i mean i would assume so since i use the computer. i just dont understand...

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Something else to try
Jan 23, 2015 7:09PM PST

It could sound is if your PC didn't shut down but went into some other mode like standby. This could be a setting or maybe even a BIOS issue. Can you try making a live Linux CD and boot from that? Do a shutdown from the disk. If the PC shuts down normally and no fans keep running, it's hardware and not software. I don't know of any PSs or MBs that do a cooldown cycle but you didn't tell anything about your hardware. If determined to be hardware, I'd try resetting the BIOS to defaults or, at the extreme end, re-flashing your BIOS with the latest image.

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Answer
The fans are on because...
Jan 23, 2015 6:55AM PST

the power supply is getting an "on signal" from the cpu or something is not right on the PS. But when you reset (power off) then it work ok which suggest maybe PS is not the problem. However, PS are inexpensive and easy to replace. Good luck.

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Answer
So it's never worked right.
Jan 23, 2015 8:25AM PST

This could be caused by a bum install of the OS to bum boards, outdated BIOS and more. There is no one clear cause for this as causes are all over the map but in short it sounds like it's hanging on shutdown.

To sniff out if it's the BUM OS issue I boot SAFE MODE and shutdown from there. If that works you talk to those that installed the OS.
Bob

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It worked before only recently did this happen
Jan 23, 2015 8:45AM PST

Only for about the last 2 weeks has this problem been occurring. before it worked totally normal. and what is a BUM?>

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did you install
Jan 23, 2015 10:17AM PST

a software that is for reading temperatures or "controlling" temperatures?

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(NT) Did the SAFE MODE boot work OK?
Jan 24, 2015 1:12AM PST
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no
Jan 24, 2015 2:02PM PST

No it had no effect but the fans were really loud while i was in safe mode and when i shut down i couldnt tell that it it had shut down cause the fans were already running fast. umm also when i turned my power supply off to get them to stop when i tried rebooting my computer it too me like 3 hours to get it to come back on should i not do that again?

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Problems restarting sound capacitor related
Jan 24, 2015 9:42PM PST

Either they fail to charge or discharge properly. The potential issues are many. I posted above to try a bootable CD of Linux but you could use some utility with an embedded OS. Disconnect your hard drive and boot from something else. Shut down and see if the fans still act the same. If they do, you have a hardware issue. Your motherboard and power supply both contain electrolytic capacitors which can cause a variety of problems when they don't function properly.

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umm
Jan 25, 2015 3:04AM PST

I dont know how to boot from something else can you explain how to do that...

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Re: boot
Jan 25, 2015 3:17AM PST

If you put a bootable CDD/DVD in the CD drive, and boot with the hard disk disconnected, it boots from the CD/DVD.

If you put a bootable CDD/DVD in the CD drive, and boot with the hard disk still connected, thre boot behavior is undefined, because it's a setting in the BIOS. So it might be that it still boots from the hard disk. Then then you have to go into the BIOS setup to change that setting (magic key #1 early in the boot) or press the magic key #2 at that same early moment in the boot that lets you choose what device to boot form.

What those magic keys are should be mentioned in the user manual of your PC or motherboard. It's differnet for different makes and models. Since it was custom built I assume it came with the motherboard manual, so that's easy.

Kees

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Starting to sound like a hardware issue.
Jan 25, 2015 3:17AM PST

3 hours is beyond reason. Even this old Pentium 90 MHz booted faster.
https://www.youtube.com/watch?v=lv3igBzWqTA

At 3 hours something is broke, failing or there is some severe infection.

Did you inspect for BAD CAPS?

Your questions may be telling me you are new to PC repair work. Also, some of those questions are on google so you need to start applying yourself or you may end up with a big repair bill.
Bob

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ah, maybe
Jan 23, 2015 10:16AM PST

they have some fan control software interacting with the motherboard that is causing it. I thought it odd if they were all or most plugged direct to PSU that there would be any change between full on and full off.

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Answer
Ok guys, are we...
Jan 25, 2015 3:18PM PST

going to analysis this thing to death? If what OP said about the fan running very fast is true then the PS is no longer regulating. 350watts Antec PS at frys for $29. I got a Logisys case with 450w. ps. for $39 total today.

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OP says all fans...not just PS
Jan 25, 2015 5:23PM PST

It also doesn't sound as if this person has done anything that's been suggested or offered any clarification or updates. That's the best reason to move on, IMO.