What's the PWR_FAN header for?

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

On Fri, 29 Jul 2005 01:39:32 GMT, milleron
<millerdot90@SPAMlessosu.edu> wrote:

>On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
>I've assumed that it's the proper place to connect the three-pin fan
>header plug from my PSU (Antec TruePower II). I don't think the
>manual says anything more about it than to label it.
>Clearly, it would NOT be there to provide power to that particular
>fan, so I deduce that it's there to provide rpm monitoring for the PSU
>fan.
>
>But the only fan speeds I can find reported are the CPU and the
>CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
>nVidia Monitor. What am I missing or misunderstanding here?
>
>Thanks,
>
>Ron

See 2-24 of the manual (PDF), it's just another fan header.

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

In article <ts1je11pu259rvaj146cb5ee2v6c1fh4ie@4ax.com>,
miller.90@spamlessosu.edu wrote:

> On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
> I've assumed that it's the proper place to connect the three-pin fan
> header plug from my PSU (Antec TruePower II). I don't think the
> manual says anything more about it than to label it.
> Clearly, it would NOT be there to provide power to that particular
> fan, so I deduce that it's there to provide rpm monitoring for the PSU
> fan.
>
> But the only fan speeds I can find reported are the CPU and the
> CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
> nVidia Monitor. What am I missing or misunderstanding here?
>
> Thanks,
>
> Ron

The Premium manual lists CPU, CHA1, CHIP as the three fan
speed monitoring channels. It would seem they ran out of
channels, and considered the CHIP header to be more important
than the PSU header. Now, normally, there would be no need
to put +12V on that header, but perhaps +12V and GND are the
only connections.

Assuming your board has an ITE IT8712 hardware monitor chip,
there are actually five fan control channels and five fan
monitoring channels. If the motherboard has a GAME/MIDI header,
two pins from the fan control group and two pins from the
fan monitoring group, are hijacked to make joystick interface
pins. That leaves three channels of fan control and three
channels of RPM monitoring. Seeing as the manual lists
CPU, CHA1, CHIP as the monitor headers, any other headers
are at best just power plugs for fans. You could check to see
if they have power, by plugging in a fan (with the power off!).

Paul

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

On Thu, 28 Jul 2005 22:36:56 -0500, Ed <spam@hotmail.com> wrote:

>On Fri, 29 Jul 2005 01:39:32 GMT, milleron
><millerdot90@SPAMlessosu.edu> wrote:
>
>>On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
>>I've assumed that it's the proper place to connect the three-pin fan
>>header plug from my PSU (Antec TruePower II). I don't think the
>>manual says anything more about it than to label it.
>>Clearly, it would NOT be there to provide power to that particular
>>fan, so I deduce that it's there to provide rpm monitoring for the PSU
>>fan.
>>
>>But the only fan speeds I can find reported are the CPU and the
>>CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
>>nVidia Monitor. What am I missing or misunderstanding here?
>>
>>Thanks,
>>
>>Ron
>
>See 2-24 of the manual (PDF), it's just another fan header.

Thanks for the reply, but I did read the manual before posting.
Although the PWR_FAN header is pictured there on 2-24, it certainly
does not state that it's "just another fan header" and definitely does
not say anything about its rpm-monitoring capability. In fact, it
gives no information about it (other than that it's not governed by
Q-Fan), which is why I posted the question here.



Ron

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

Some power supplies have a separate lead that can be plugged into the Fan
Header on the motherboard. The motherboard will then controll the power
supply fan or it will just monitor the speed of the fan.


"milleron" <millerdot90@SPAMlessosu.edu> wrote in message
news:ts1je11pu259rvaj146cb5ee2v6c1fh4ie@4ax.com...
> On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
> I've assumed that it's the proper place to connect the three-pin fan
> header plug from my PSU (Antec TruePower II). I don't think the
> manual says anything more about it than to label it.
> Clearly, it would NOT be there to provide power to that particular
> fan, so I deduce that it's there to provide rpm monitoring for the PSU
> fan.
>
> But the only fan speeds I can find reported are the CPU and the
> CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
> nVidia Monitor. What am I missing or misunderstanding here?
>
> Thanks,
>
> Ron

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

On the P4C800 the header reads the power supply fan fine, if you have a
supply with the lead. It outputs it to the Asus Probe program. Funny they
wouldn't do that on your board as well.
"milleron" <millerdot90@SPAMlessosu.edu> wrote in message
news:1ovke19sl828fgl7vg90bgo4m2r8anuhv9@4ax.com...
> On Fri, 29 Jul 2005 01:47:16 -0400, nospam@needed.com (Paul) wrote:
>
>>In article <ts1je11pu259rvaj146cb5ee2v6c1fh4ie@4ax.com>,
>>miller.90@spamlessosu.edu wrote:
>>
>>> On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
>>> I've assumed that it's the proper place to connect the three-pin fan
>>> header plug from my PSU (Antec TruePower II). I don't think the
>>> manual says anything more about it than to label it.
>>> Clearly, it would NOT be there to provide power to that particular
>>> fan, so I deduce that it's there to provide rpm monitoring for the PSU
>>> fan.
>>>
>>> But the only fan speeds I can find reported are the CPU and the
>>> CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
>>> nVidia Monitor. What am I missing or misunderstanding here?
>>>
>>> Thanks,
>>>
>>> Ron
>>
>>The Premium manual lists CPU, CHA1, CHIP as the three fan
>>speed monitoring channels. It would seem they ran out of
>>channels, and considered the CHIP header to be more important
>>than the PSU header. Now, normally, there would be no need
>>to put +12V on that header, but perhaps +12V and GND are the
>>only connections.
>>
>>Assuming your board has an ITE IT8712 hardware monitor chip,
>>there are actually five fan control channels and five fan
>>monitoring channels. If the motherboard has a GAME/MIDI header,
>>two pins from the fan control group and two pins from the
>>fan monitoring group, are hijacked to make joystick interface
>>pins. That leaves three channels of fan control and three
>>channels of RPM monitoring. Seeing as the manual lists
>>CPU, CHA1, CHIP as the monitor headers, any other headers
>>are at best just power plugs for fans. You could check to see
>>if they have power, by plugging in a fan (with the power off!).
>>
>> Paul
>
> Thanks, Paul. So it looks as though the header marked "PWR_FAN" is,
> in reality, for any fan OTHER THAN the "PWR FAN" because all the PSU
> fan requires is rpm monitoring, but the only thing that header
> actually provides is power. Asus was really stupid on this one, then.
>
> Ron

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

I've got an Antec 480 and it typically runs at about 1850 rpm at idle and
maybe 2300 rpm in 2D Apps. In 3D games it typically runs at about 4500 rpm.
This is with ambiant room temps of about 82 degrees this time of year.
"milleron" <millerdot90@SPAMlessosu.edu> wrote in message
news:7h8ne15j547fqlm9alfk3j2udq4nk9hdom@4ax.com...
> On Sat, 30 Jul 2005 15:44:17 GMT, "Tom Dauphin"
> <tdauphin@earthlink.net> wrote:
>
>>On the P4C800 the header reads the power supply fan fine, if you have a
>>supply with the lead. It outputs it to the Asus Probe program. Funny they
>>wouldn't do that on your board as well.
>
> Well, this board does have a game-port header, so, as Paul explained,
> Asus seems to have pirated a connection from the PWR_FAN header to
> make the game port functional. It's the best explanation I've had so
> far. I have my PSU plug connected to the PWR_FAN header, and there's
> no readout ANYwhere.
> Too bad, because I'm really curious about how much variation there is
> in the TruePower II's fan.
> Interestingly, Paul has a reference stating that on my board, the CHIP
> header provides monitoring. However, I do have a small 80mm fan with
> rpm sensing connected there, and there's no readout for that one,
> either. The only two I can see are CPU and CHA1_FAN which, probably
> not coincidentally, are the only two headers on this board controlled
> by Q-Fan.
>
>>"milleron" <millerdot90@SPAMlessosu.edu> wrote in message
>>news:1ovke19sl828fgl7vg90bgo4m2r8anuhv9@4ax.com...
>>> On Fri, 29 Jul 2005 01:47:16 -0400, nospam@needed.com (Paul) wrote:
>>>
>>>>In article <ts1je11pu259rvaj146cb5ee2v6c1fh4ie@4ax.com>,
>>>>miller.90@spamlessosu.edu wrote:
>>>>
>>>>> On my A8N-SLI Premium, one of the fan headers is labeled "PWR-FAN."
>>>>> I've assumed that it's the proper place to connect the three-pin fan
>>>>> header plug from my PSU (Antec TruePower II). I don't think the
>>>>> manual says anything more about it than to label it.
>>>>> Clearly, it would NOT be there to provide power to that particular
>>>>> fan, so I deduce that it's there to provide rpm monitoring for the PSU
>>>>> fan.
>>>>>
>>>>> But the only fan speeds I can find reported are the CPU and the
>>>>> CHA1_FAN. This is true in BIOS, Asus Probe, Lavalys Everest, and
>>>>> nVidia Monitor. What am I missing or misunderstanding here?
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Ron
>>>>
>>>>The Premium manual lists CPU, CHA1, CHIP as the three fan
>>>>speed monitoring channels. It would seem they ran out of
>>>>channels, and considered the CHIP header to be more important
>>>>than the PSU header. Now, normally, there would be no need
>>>>to put +12V on that header, but perhaps +12V and GND are the
>>>>only connections.
>>>>
>>>>Assuming your board has an ITE IT8712 hardware monitor chip,
>>>>there are actually five fan control channels and five fan
>>>>monitoring channels. If the motherboard has a GAME/MIDI header,
>>>>two pins from the fan control group and two pins from the
>>>>fan monitoring group, are hijacked to make joystick interface
>>>>pins. That leaves three channels of fan control and three
>>>>channels of RPM monitoring. Seeing as the manual lists
>>>>CPU, CHA1, CHIP as the monitor headers, any other headers
>>>>are at best just power plugs for fans. You could check to see
>>>>if they have power, by plugging in a fan (with the power off!).
>>>>
>>>> Paul
>>>
>>> Thanks, Paul. So it looks as though the header marked "PWR_FAN" is,
>>> in reality, for any fan OTHER THAN the "PWR FAN" because all the PSU
>>> fan requires is rpm monitoring, but the only thing that header
>>> actually provides is power. Asus was really stupid on this one, then.
>>>
>>> Ron
>>
>
> Ron

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

On Sat, 30 Jul 2005 15:58:32 GMT, milleron <millerdot90@SPAMlessosu.edu>
wrote:

> I have my PSU plug connected to the PWR_FAN header, and there's
>no readout ANYwhere.
>Too bad, because I'm really curious about how much variation there is
>in the TruePower II's fan.

Just plug it into the RPM-monitored header that isn't the CPU fan. Since
the PSU fan isn't powered by header, any fan-speed control of the board
won't affect it, you'll just get the current rpm readout.

Cheers - Jaimie