Connect a 4 Pin Fan to P4C800-ED (for RPM)- Where to Find Adapter?

  • Thread starter Thread starter QZ
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Q

QZ

I just built a new PC with P4C800-ED, and I replaced the case fans with
better ones, but I
got all 4 pin types, but now I want to monitor the RPM of one of the front
case fans. It is difficult to get to the fan, so I would prefer to get an
adapter to connect the fan to the mainboard, to monitor the RPM.
I have searched, and all I can find is a 4 pin to 3 pin w/o RPM wire.
Does anyone know of a 4 pin to 3 pin with RPM wire? (or a 4 pin to 4 pin
with addtl RPM wire, if it exists.)
Finding 3 pin to 4 pin adapters with RPM is easy, but of no use to me.

Thanks,
QZ
 
QZ said:
I just built a new PC with P4C800-ED, and I replaced the case fans with
better ones, but I
got all 4 pin types, but now I want to monitor the RPM of one of the front
case fans. It is difficult to get to the fan, so I would prefer to get an
adapter to connect the fan to the mainboard, to monitor the RPM.
I have searched, and all I can find is a 4 pin to 3 pin w/o RPM wire.
Does anyone know of a 4 pin to 3 pin with RPM wire? (or a 4 pin to 4 pin
with addtl RPM wire, if it exists.)
Finding 3 pin to 4 pin adapters with RPM is easy, but of no use to me.

Thanks,
QZ
Click to expand...

Good luck. Might as well swap out the 4-pin fans for 3-pin
fans. Seriously doubt that the 4-pin fans are wired for the
tachometer lead...just power.
 
Good luck. Might as well swap out the 4-pin fans for 3-pin
fans. Seriously doubt that the 4-pin fans are wired for the
tachometer lead...just power.
Click to expand...


I raised this question several months ago, after noticing that a
Panaflo 80 mm fan had space for a third wire where the wires enter the
fan motor body. But after some messages from other newsgroup people,
and consulting the Panaflo web site, it turns out that there is no way
to get fan monitoring out of a fan that wasn't designed with it.

Someone posted a "fix" for this problem, but considering the price of
fans, it simply wasn't worth it.

--W--
 
First of all, a "4 pin fan" is really a "2-pin" fan -- power (almost
always +12 volts) and ground.

And a "3-pin fan" is the same as the "2-pin" fan except that the fan
provides an additional signal, a tachometer output so that it's speed
(in RPMs) can be measured.

The tachometer signal isn't required. There ARE adapters from 4-pin fan
connections to 3-pin fan connections in both directions, they usually
cost about $2 but they are hard to find.

Generally, except for the CPU fan, the missing tachometer signal is
irrelevant. Systems can be set, and may be set, to "alarm" in some
cases if the speed is too low, but these alarms (in the BIOS and/or in
programs like Asus Probe) can be disabled.
 
Barry Watzman said:
The tachometer signal isn't required. There ARE adapters from 4-pin fan
connections to 3-pin fan connections in both directions, they usually
cost about $2 but they are hard to find.
Click to expand...

So, if the adapter has the tachometer wire, you are saying it can read the
RPM of a fan by connecting to the fan's 4 wire connection?
If so, do you know of any place that had them in the past?
Generally, except for the CPU fan, the missing tachometer signal is
irrelevant. Systems can be set, and may be set, to "alarm" in some
cases if the speed is too low, but these alarms (in the BIOS and/or in
programs like Asus Probe) can be disabled.
Click to expand...

How can Asus Probe's alarm work w/o tachometer, since, AFAIK, it goes by
RPM?
 
So, if the adapter has the tachometer wire, you are saying it can read the
RPM of a fan by connecting to the fan's 4 wire connection?
If so, do you know of any place that had them in the past?
Click to expand...
You said "had." I had a delta fan that drew a little too much current
for my MB header to supply. I got an adapter that converted the 3-pin
connector to a 4-pin molex, BUT it had a third connector that inserted
on the MB CPU FAN header so that the RPM function could still be
monitored while the fan drew current from the PSU. I got it from
KDComputers ( www.kdcomputers.com) almost three years ago, but
checking there now, I don't see it. They do still sell a simple 3-pin
to 4-pin adapter, but it has no ability to connect the tachometer.
These 3-pin-to4-pin adapters are easy to find online.
However, if you want to power a fan from the PSU and maintain its tach
function, I think you're going to have to buy a couple of these things
and mod them yourself because it looks like no one any longer sells
the cable I described, at least no vendor I can Google.
How can Asus Probe's alarm work w/o tachometer, since, AFAIK, it goes by
RPM?
Click to expand...

Ron
 
Milleron said:
I got an adapter that converted the 3-pin
connector to a 4-pin molex, BUT it had a third connector that inserted
on the MB CPU FAN header so that the RPM function could still be
monitored while the fan drew current from the PSU.
Click to expand...

No, I have a 4-pin fan, so I am looking for a 4-pin to 3-pin adapter with
RPM.
 
QZ said:
No, I have a 4-pin fan, so I am looking for a 4-pin to 3-pin adapter with
RPM.
Click to expand...

A 4pin fan won't have the RPM wire, since the 4 pins are for a 4pin HDD
Molex connector.
 
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