cpu fan not working

[JohnJAdamson]

Hi
I've had a computer for around 6 months now and it has seen much heavy use
but has been very stable.
Anyway about 2 weeks ago it crashed with a blue stop screen. I hoped that it
was a one off freak event but it crashed again yesterday.
I took the back off and noticed that the CPU fan wasn't working. It's power
lead is connected into the motherboard. There are 2 other 3 pin connectors
on the motherboard for other fans so I tried it in those with no success. I
happen to have a spare fan which I tried but which also didn't work. Which
lead me to believe there might be something wrong with the motherboard. I
used a volt meter to measure the voltage across the red and black pins and
it came with around 4.5 volts.
Am I right in thinking the fan needs 12v to work?

I haven't got any wires to connect the fan to a battery to test it. But the
fact that another fan didn't works leads me to suspect that the fans are
alright.

So has anyone got any advice regarding what might be amiss and what
components I should buy. I've had a look using Goolge and the Power Supply
Unit (PSU) keeps coming up as a possible culprit.
Thanks

 

[philo]

Hi
I've had a computer for around 6 months now and it has seen much heavy use
but has been very stable.
Anyway about 2 weeks ago it crashed with a blue stop screen. I hoped that
it was a one off freak event but it crashed again yesterday.
I took the back off and noticed that the CPU fan wasn't working. It's
power lead is connected into the motherboard. There are 2 other 3 pin
connectors on the motherboard for other fans so I tried it in those with
no success. I happen to have a spare fan which I tried but which also
didn't work. Which lead me to believe there might be something wrong with
the motherboard. I used a volt meter to measure the voltage across the red
and black pins and it came with around 4.5 volts.
Am I right in thinking the fan needs 12v to work?

I haven't got any wires to connect the fan to a battery to test it. But
the fact that another fan didn't works leads me to suspect that the fans
are alright.

So has anyone got any advice regarding what might be amiss and what
components I should buy. I've had a look using Goolge and the Power Supply
Unit (PSU) keeps coming up as a possible culprit.

if the power headers on the mobo are bad
just power the cpu fan from one the the power leads designed for connection
to your harddrives.

 

[Mxsmanic]

I took the back off and noticed that the CPU fan wasn't working. It's power
lead is connected into the motherboard. There are 2 other 3 pin connectors
on the motherboard for other fans so I tried it in those with no success. I
happen to have a spare fan which I tried but which also didn't work. Which
lead me to believe there might be something wrong with the motherboard. I
used a volt meter to measure the voltage across the red and black pins and
it came with around 4.5 volts.
Am I right in thinking the fan needs 12v to work?

I haven't got any wires to connect the fan to a battery to test it. But the
fact that another fan didn't works leads me to suspect that the fans are
alright.

I had a similar problem with a cheap motherboard. The power to the
fan failed, and so the fan stopped, and the CPU overheated, with
permanent damage. At first I thought the fan itself had gone bad, but
in fact it was the power to the fan. But the MB was ruined either
way, so I had to replace it (the MB and CPU). I still have the fan,
though.

 

[chris]

Hi
I've had a computer for around 6 months now and it has seen much heavy use
but has been very stable.
Anyway about 2 weeks ago it crashed with a blue stop screen. I hoped that it
was a one off freak event but it crashed again yesterday.
I took the back off and noticed that the CPU fan wasn't working. It's power
lead is connected into the motherboard. There are 2 other 3 pin connectors
on the motherboard for other fans so I tried it in those with no success. I
happen to have a spare fan which I tried but which also didn't work. Which
lead me to believe there might be something wrong with the motherboard. I
used a volt meter to measure the voltage across the red and black pins and
it came with around 4.5 volts.
Am I right in thinking the fan needs 12v to work?

I haven't got any wires to connect the fan to a battery to test it. But the
fact that another fan didn't works leads me to suspect that the fans are
alright.

So has anyone got any advice regarding what might be amiss and what
components I should buy. I've had a look using Goolge and the Power Supply
Unit (PSU) keeps coming up as a possible culprit.
Thanks

You can try inside your bios under power management and see if there's
an on\off,I'd just hard wire as suggested.

C.

 

[Tim]

I had a similar problem with a cheap motherboard. The power to the
fan failed, and so the fan stopped, and the CPU overheated, with
permanent damage. At first I thought the fan itself had gone bad, but
in fact it was the power to the fan. But the MB was ruined either
way, so I had to replace it (the MB and CPU). I still have the fan,
though.

Which CPU?

 

[Mxsmanic]

Which CPU?

I think it was an AMD Athlon 1500+ ... it was whatever came with that
cheap computer, and it was an AMD processor. The fact that the AMD
processor reacted so inelegantly to a fan failure is why the machine I
built to replace it uses an Intel processor.

 

[David Maynard]

Tim writes:




I think it was an AMD Athlon 1500+ ... it was whatever came with that
cheap computer, and it was an AMD processor. The fact that the AMD
processor reacted so inelegantly to a fan failure is why the machine I
built to replace it uses an Intel processor.

I like that phraseology for what I presume was catastrophic failure: an
'inelegant response'.

Indeed

 

[Mxsmanic]

I like that phraseology for what I presume was catastrophic failure: an
'inelegant response'.

Well, it didn't burst info flame, at least, but it had a funny smell
and part of the plastic in the CPU fan mounting had softened slightly
where it contacted the radiator. I know it got to at least 130° C,
and probably much more.

 

[Tim]

I think it was an AMD Athlon 1500+ ... it was whatever came with that
cheap computer, and it was an AMD processor. The fact that the AMD
processor reacted so inelegantly to a fan failure is why the machine I
built to replace it uses an Intel processor.

I wasn't until AMD's Athlon64 that they finally got built-in thermal
protection, shutting the system down if they overheat. Pentium 4s go a step
further and actually throttle down the CPU speed and continue to work. I
think Intel's thermal protection patents delayed AMD's own thermal
protection.