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Power Supply Fan starts and stops repeatedly?

by pencewd_01 / September 10, 2010 12:04 PM PDT

Just noticed that my power supply fan starts and stops repeatably? Will it eventual just stop and screw my pc up?

Should I go ahead and get a new power supply?

I haven't had any over heating or crashing issues with it.

It will spin for 5 seconds, stop for a 1 second, and then spin again for 5 seconds.

power suppy is 650 or 600 watts

Could a connection just be loose? I have never opened up my power suppy, but I built this pc.

specs below:
System Information report written at: 09/10/10 21:02:30
System Name: PENCEWD-PC
[System Summary]

Item Value
OS Name Microsoft Windows 7 Ultimate
Version 6.1.7600 Build 7600
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Name PENCEWD-PC
System Manufacturer System manufacturer
System Model System Product Name
System Type x64-based PC
Processor Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s)
BIOS Version/Date Phoenix Technologies, LTD ASUS P5N-D ACPI BIOS Revision 1204, 1/7/2010
SMBIOS Version 2.4
Windows Directory C:\Windows
System Directory C:\Windows\system32
Boot Device \Device\HarddiskVolume2
Locale United States
Hardware Abstraction Layer Version = "6.1.7600.16385"
User Name pencewd-PC\pencewd
Time Zone Central Daylight Time
Installed Physical Memory (RAM) 4.00 GB
Total Physical Memory 4.00 GB
Available Physical Memory 2.66 GB
Total Virtual Memory 8.00 GB
Available Virtual Memory 6.52 GB
Page File Space 4.00 GB
Page File C:\pagefile.sys

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New designs do that.
by R. Proffitt Forum moderator / September 11, 2010 12:03 AM PDT

Ask the machine's maker if they used thermally controlled fans. If so, BONUS. The fans last much longer.

However it can annoy some users which we'll have to find a way to keep the fans running.

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Power Supply Fan, External fan starts and stops repeatedly?
by baap123 / June 17, 2015 8:11 AM PDT

I did cleanup of Desktop from dust etc, and this problem started, did PSU check it is working fine, but when connected to Motherboard it is failing. I removed CPU too. What could be wrong ?
Last attempt, will apply thermal compound and try again.

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What techs do...
by R. Proffitt Forum moderator / June 17, 2015 8:38 AM PDT

Is when the motherboard fan control fails like that, the better techs offer to connect the fan direct to the power supply, change the motherboard or add an small speed control board.

Some motherboards have other case fan connections so I try that for case fans since one might have failed.

If it's just a wonky speed control we can avoid replacing the motherboard. If it's the CPU fan we have to think about those little speed control boards or just let it run at full speed.

EXAMPLE: http://www.newegg.com/Product/Product.aspx?Item=N82E16835118217
Some review tried it on a water pump? Strange idea. It's for fans.

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it's working correctly
by James Denison / June 17, 2015 6:02 PM PDT

It's summer. Your indoor temp is probably higher, so it's kicking on when it didn't during winter. Make sure you have more than just the PSU fan to exhaust heat from the case.

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Power Supply Fan starts and stops repeatedly?
by baap123 / June 18, 2015 8:47 AM PDT

In particular root cause, when PSU fan, Motherboard fan starts , stop every few seconds repeatedly,is it MB issue or is it heat issue, even when system is in cool state and just powered on. I understand when Temp shoots up, either MB or System fan spins at high speed till temperature has come down. PSU , i tested by short circuiting and PSU fan works fine , this is happening only with Motherboard.

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this is a fan on the motherboard?
by James Denison / June 18, 2015 9:28 AM PDT

Is it the CPU fan, or one of the SYS fans?

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Sys Fan, Cpu Fan, PSU Fan
by baap123 / June 18, 2015 12:35 PM PDT

PSU Fan, CPU Fan, Fan connected to MB, all 3 same behavior.

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Time to move to old fan supply methods.
by R. Proffitt Forum moderator / June 18, 2015 12:57 PM PDT

Sometimes the motherboard fan connections die. There are cheap fixes for that.

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not a good sign
by James Denison / June 18, 2015 5:00 PM PDT

I'd replace the PSU or at least try another known good one to test if the old one is bad. A multimeter will tell if old PSU voltage is wrong, but won't do load test on it. The alternate is to plug all fans direct to a power cord from the PSU and if they still act the same speeding up and down, especially at the same time, you must replace the PSU.

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Power Supply Fan starts and stops repeatedly?
by caliskaz / June 30, 2015 9:31 AM PDT

pencewd_01, it might just be a fan that’s being controlled by temperature feedback. Since you cleared your desktop from dust, you might have lower temperature of the fan regulating temperature properly. You can check that from OEM. Please note that almost all PSU fans for laptops are thermally controlled and I highly suspect that the one you’re referring to will also be thermally controlled.

(tagline removed)

Note: Moderator edited out tagline link. Please don't add taglines as your web site promotion isn't allowed here.

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I changed the PSU, and viola.
by Rezolution77 / February 4, 2016 10:17 PM PST

The nice thing about hardware, that is, if you have the needed parts.
Unfortunately, doing this, did not answer my question.

What fixed it, was answered. .......But Why???
And could the psu function again normally, with proper maintenance?

Here is one I haven't tried yet, but may, if time and patience allow.

Samm, a trusted tech had this to say....

OK, please follow these instructions very carefully :

1) Disconnect the power cord from the back of the computer & open up the case.

2) Wear an anti-static band, or, at very least discharge static by touching a metal surface.
(of course, nothing on the inside of your pc)

3) Disconnect the PSU's power connectors from the motherboard.

4) Remove PCI cards & disconnect ALL drive cabling from the MOTHERBOARD.
-Also disconnect any internal USB fly leads from the motherboard.

5) Now, you should have ONLY the cpu+heatsink/fan, memory, & video card installed.
Locate the round silver battery in the bottom right corner of the board.
Just below it, a plastic jumper (cap) should be covering (pins 1+2) with pin 3 open/bare.
It will be marked JP1.

6) Next, move the jumper (cap) to cover (pins 2-3) instead.
Leave in this position for 30 seconds, then, return the jumper to its original position (pins 1-2).

6) Reconnect the psu's power connectors to the motherboard.
Make sure that the case speaker or buzzer is connected also.

7) Make sure the only external devices connected are the keyboard/mouse & monitor. Reconnect the front panel power switch (case wiring labeled PWRSW )

Cool Turn on. ( make sure your psu switch is also on, and now plugged in )

What happens, i.e do you hear any beeps? Does the power stay on this time?
Do the keyboard lights flash up once?

-Personal Note -
When you re-installed the cpu into the new motherboard, did you remove the old thermal compound & reapply fresh compound to the cpu and/or heatsink?

If you didn't, then DO NOT POWER ON THE SYSTEM - Until you have.

Anyway, I will listen in on this discussion, hoping a 3rd echelon tech can be more specific.

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