Heatsink Fan doesn't run

[Richard Harvey]

I am trying to build a computer with:
- an ASUS M3A32-MVP Deluxe motherboard
- an AMD Phenom processor (with heatsink)
- an Ultra 600 watt ATX Power Supply
- Kingston memory (4GB)

When I put it together the first time and plugged it in, the LED light on the motherboard lit up; but, the heatsink fan didn't start up. I checked the system all over and brought in a consultant to look at it and he decided that the motherboard wasn't working.

I returned the motherboard for repair and they sent me a new motherboard.

I've put it together again with just the items listed above and the heatsink still doesn't run.

I have plugged the heatsink fan into the CPU-fan socket of the motherboard.

I have connected the power source to the motherboard via a 24-pin connector.

I have connected the power source to the motherboard via a 4-pin + 12v connector.

I think my next step is to replace the heatsink fan, but ...

Does the heatsink fan require anything other than power to run?
Specifically
- if the processor is malfunctioning, will that stop the heatsink fan?
- if the memory is malfunctioning, will that stop the heatsink fan?
- is it possible that the power supply is putting out enough energy to light the LED light, but not enough to run the heatsink fan?

Any other ideas as to why the heatsink fan doesn't work?

[davy]

The fan should run as soon as you press the power 'ON' button, you need to check if the fan spins easily and not jamming on anything, it does seem unreal that two mobos have the same problem... but one never knows and guess there is always a first time.

The fan could be faulty so better to test it first and can be done quite easily, you can of course check the fan by connecting a 12V battery or 12V dc power supply to the two power leads, the fans should spin providing the dc polarity is correct.

NOTE: Some fans have three wires one is for the tacho pulse that reads the fans RPM, this wire can be ignored. all the fan needs is about 12V of dc power to run.

Wonder if this 'tacho' wire has been connected into its connector correctly during manufacture displacing the 12 volt feed... maybe worth looking into?

As you mentioned there could well be a problem with the 12 volt rail on the power supply and this needs to be checked too if the fan appears to run ok.

davy

[Richard Harvey]

Thanks Davy for the quick response.

I'll test the heatsink fan separately and let you know what happens. It'll be a couple of days before I get back.

Thanks, Richard

[davy]

You could use a small wall wart set between 9 and 12V, bear in mind the dc polarity, if you connect the wrong way the fan won't spin....

... the knack in making the connections to the plug is to use two fine sewing needles or tacking pins push them in at the wire end is easier than pushing them at plug pin end, just hold the wires on to them is easier.

davy