Fan power

  • Thread starter Thread starter Eric
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Eric

I have here an ASUS CUW-AM motherboard
(http://h10025.www1.hp.com/ewfrf/wc/...ct=60421&os=209&printable=yes&encodeUrl=true&).
I only see 2 connectors for fan power.
On the spec sheet they are labeled PS_FAN and SYS_FAN.
The CPU fan is plugged in to the one labeled SYS_FAN.
This board was in a mini tower and I moved it into a mid tower.
I don't know if the mini tower had a case fan or if it worked.
I plugged the mid tower case fan into the PS_FAN port and it didn't do
anything.
I plugged the case fan into the SYS_FAN port and the CPU fan into the PS_FAN
port, then the case fan ran and the CPU fan didn't.
I'm guessing the PS part means power supply, as to say the mini tower had a
separate plug for a fan in the power supply.

Is a PS_FAN port supposed to power a case fan and/or CPU fan?
Are they the wrong type of fan for it or is the port just dead?
Is there any way to revive a dead fan power port on a motherboard?
Is it critical to have a working case fan in a mid tower that has working
fans on the power supply and CPU?
 
The power cords from the power supply are 12 volt.
The fans should have the voltage listed on them.
Most of them are 12 volt.
Try them out.
 
Eric said:
I have here an ASUS CUW-AM motherboard
(http://h10025.www1.hp.com/ewfrf/wc/...ct=60421&os=209&printable=yes&encodeUrl=true&).
I only see 2 connectors for fan power.
On the spec sheet they are labeled PS_FAN and SYS_FAN.
The CPU fan is plugged in to the one labeled SYS_FAN.
This board was in a mini tower and I moved it into a mid tower.
I don't know if the mini tower had a case fan or if it worked.
I plugged the mid tower case fan into the PS_FAN port and it didn't do
anything.
I plugged the case fan into the SYS_FAN port and the CPU fan into the PS_FAN
port, then the case fan ran and the CPU fan didn't.
I'm guessing the PS part means power supply, as to say the mini tower had a
separate plug for a fan in the power supply.

Is a PS_FAN port supposed to power a case fan and/or CPU fan?
Are they the wrong type of fan for it or is the port just dead?
Is there any way to revive a dead fan power port on a motherboard?
Is it critical to have a working case fan in a mid tower that has working
fans on the power supply and CPU?
Click to expand...

Read the manual. My interpretation of PS_FAN is that of the
header for the Power Supply Fan tachometer. That is, PS_FAN
supplies no power to drive a fan but will read the fan speed
of the fan the PSU, which is driven internally off the PSU
circuitry. There should be a separate header for the CPU fan.
This one might be linked to feedback controls to regulate the
CPU fan speed.
 
Squire said:
The power cords from the power supply are 12 volt.
The fans should have the voltage listed on them.
Most of them are 12 volt.
Try them out.
Click to expand...
Actually, the drive cables have 5 volt circuits too, but the fan knows
which voltage to use.
 
Ghostrider said:
Read the manual. My interpretation of PS_FAN is that of the
header for the Power Supply Fan tachometer. That is, PS_FAN
supplies no power to drive a fan but will read the fan speed
of the fan the PSU, which is driven internally off the PSU
circuitry. There should be a separate header for the CPU fan.
This one might be linked to feedback controls to regulate the
CPU fan speed.
Click to expand...

Of course it was a donated computer that I pulled the motherboard from, and
I'm putting it into a slower computer we already had, so we have no manual
for it. I think you must be interpreting it right though if I understand
you. I did plug in the power supply from the computer the motherboard was
in, which had a separate plug for the fan, and the fan did work. The power
supply on the computer we're moving the motherboard into has no separate
plug for it's fan, it just works. That PS_FAN port must be just telling the
power supply to turn on the fan, while the SYS_FAN port is actually
supplying power.

I'm guessing it's not going to cause any serious damage not to run the case
fan, since the fan on the CPU and the fan in the power supply both work.
The air from the power supply fan is actually blowing down into the PC so
I'm just leaving out the case fan and guessing that will get enough air
flowing out where the case fan was.
 
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