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CPU fan spins up momentarily, then stops and BIOS reports error

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  • BIOS
  • Fan
  • CPUs
Last response: in CPUs
November 2, 2013 1:57:29 AM

My fan was working correctly a few days ago. Today, I powered up my computer but the CPU fan was not spinning. The BIOS did not report any errors, though it reported the CPU fan RPM as zero. I opened up my case and tried to boot. The fan spins up momentarily, but stops spinning after the POST beep. The BIOS still did not report any error, even though it was configured to do so. I decided to ignore the problem and booted up again. This time, the fan spinned up momentarily, stopped after the POST beep, and the BIOS reported an error with the CPU fan and refused to boot. How do I solve this? I really don't want to replace the fan because it would take at least 3 weeks for a spare to arrive.

More about : cpu fan spins momentarily stops bios reports error

a c 80 à CPUs
November 2, 2013 2:25:23 AM

got another fan header on the motherboard?

can you replace the fan?

don't run machine or continually start it without the cpu fan running. it doesn't take much to destroy a cpu.
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November 2, 2013 2:29:15 AM

swifty_morgan said:
got another fan header on the motherboard?

can you replace the fan?

don't run machine or continually start it without the cpu fan running. it doesn't take much to destroy a cpu.


I have a 3 pin system fan header. The CPU fan uses 4 pins. I don't know which way to fit the 4 pin on the 3 pin.
Replacing the fan would be my last resort. I live in a remote area. It would take 3 weeks for another fan to arrive, wherever I buy one from.
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a c 80 à CPUs
November 2, 2013 2:45:38 AM

if you look closely at the 4pin, you see it will only fit one way and that it's also okay to put that 4pin on the 3pin header. try it. ( also,if it's not a cpu header it will not spin up but will run at a constant speed. and you may also have to disable the shut off or fan speed indicator in the BIOS or the machine may keep shutting down)................. replace the fan or replace fan/heatsink combo.
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November 2, 2013 4:07:17 AM

swifty_morgan said:
if you look closely at the 4pin, you see it will only fit one way and that it's also okay to put that 4pin on the 3pin header. try it. ( also,if it's not a cpu header it will not spin up but will run at a constant speed. and you may also have to disable the shut off or fan speed indicator in the BIOS or the machine may keep shutting down)................. replace the fan or replace fan/heatsink combo.


The fan spins and the BIOS reports the RPM correctly under the system fan. So the fan isn't faulty, I guess. What could be the issue now?
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a c 80 à CPUs
November 2, 2013 4:38:16 AM

if it didn't work on the old header, the old header is bad.............???? or are you saying the fan is still hooked to the old header?
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November 2, 2013 4:45:35 AM

swifty_morgan said:
if it didn't work on the old header, the old header is bad.............???? or are you saying the fan is still hooked to the old header?


The header is perfectly fine, as the fan spins up before the POST beep. I put the fan on the SYS_FAN header to see if the tachometer was bad, but the RPM is reported correctly. But putting the fan back on the CPU_FAN header makes the system report an error with the fan.
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Best solution

a c 80 à CPUs
November 2, 2013 4:55:03 AM

try a BIOS update.
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November 2, 2013 5:17:37 AM

swifty_morgan said:
try a BIOS update.


I have the latest BIOS... and the fan was working correctly a few hours ago. So I don't think it's a BIOS problem. Shall I plug in the System fan into the CPU_FAN header to check if the header has a problem?
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November 2, 2013 5:33:07 AM

I reset my BIOS and the issue disappeared. I still don't know what the problem was, but it's gone now. Thanks swifty_morgan.
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December 26, 2014 7:53:53 PM



* if you have a multimeter, measure CPU Fan Connector pins (usually 3 or 4) to find which one have +12v.? if you measure +12v and good Ground problem is the Fan, if you have another Fan test in same connector see if it spins. If you are Missing +12v at mobo."Cpu Fan Header", this is the problem.. Turn Pc off..disconnect CPU Fan 3 or 4 pin connector from the mobo. Take a look at the wires coming from Fan to Connector, the Black one is the Ground,usually first or last depending orientation, next to Black wire is Red (or Yel) which is +12v line missing he voltage from Cpu-Fan Header at Mobo. with sharp object disconnect this Red wire from the socket by pushing the latch out, pull the wire from the socket and locate any other Fan Header near-by, then add-extend this wire to the next Fan Header and connect to +12v line there (red). Connect Cpu-Fan Connector back to its header with Red Wire Pulled and carried to nearby Fan Header, recomending with series of any diode for back protection.Now turn on your pc and stop worrying about the Cpu Fan anymore.. However Fan speed will be constant since the applied regulated +12v it will be still recorded and reported via other pins connected to Mobo. Whether the problem caused by CPU or Mobo, this is the solution I overcome save me getting new CPU or Mobo..? Hoping people in same situation.. getting CPU-FAN ERRORS due Cpu-Fan Failures..Here is the By-Pass Solution.. Enjoy.. Teknofix-2014
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