Fabricate a rpm-sensing cable ..

Joe Average · Post by **Joe Average** » Sun Feb 27, 2005 11:57 pm

Hi .. bought a rheobus fancontroller recently .. works fine.
But now I want to get the rpm-readings.. which means I have to fabricate some kind of split. How do I do it? Which colour goes where?

If U look at this link U´ll get the picture:

http://www.silentpcreview.com/files/ima ... m-mfc1.jpg

It´s the "C2" cable that needs to be made..
Thus: How do I do it?

Id like to cut the cable and resolder it somehow .. not poking in the connector.

.. forgot to mention I got 3-pin 120mm Papst fans

burcakb · Post by **burcakb** » Mon Feb 28, 2005 2:49 am

on a 3-pin connector, with the two ridges pointing up and the cable end pointing away from you, the lines counting from left to right

#1: Yellow. rpm sensor wire
#2: Red, voltage wire
#3: Black, ground wire

Joe Average · Post by **Joe Average** » Mon Feb 28, 2005 3:32 am

ok thx ..

so to create my own C2-cable I just need to (the easiest way) cut the cables from the 3-pin fan .. and then:

cut the cables on a new (another) 3-pin connector (for rpm-readings) and twin them all together according to my scheme below

[MB] <=== yellow ==========> [FAN]

[RHEOBUS] <============ red ===========> [FAN]

[RHEOBUS] + [MB] <========= black ==========> [FAN]

Is this the accurate way to solve this?

EDIT: nope it wasn´t didnt get the RPM ..

sthayashi · Post by **sthayashi** » Mon Feb 28, 2005 6:37 am

It may be a little trickier than that... You may also need to have the black wire go to the motherboard as well as the Rheobus.

cpemma · Post by **cpemma** » Mon Feb 28, 2005 6:56 am

Assuming you've plugged the speed wire onto the correct mobo pin (RHS with the key down:

0-12-RPM
... === ...

Then if the controller is using PWM you may get a garbage signal.

Tibors · Post by **Tibors** » Mon Feb 28, 2005 8:28 am

Or the fan was spinning so slow that the mobo couldn't read the speed. I've seen minimum readable speeds for mobo's anywhere between 600RPM and 1000RPM. Sometimes this minimum is dependend on settings in the BIOS too.

Joe Average · Post by **Joe Average** » Mon Feb 28, 2005 2:13 pm

sthayashi said "it may be a little trickier .."

Yep .. but I splitted the black cable to both MB and Rheobus (see scheme)

Tibors said "Or the fan was spinning so slow that the mobo couldn't read the speed."

The fan ran at full speed .. that should be 1600rpm .. that cant be too low

I still havent managed to read the rpm signal via the motherboard (MB) using the rheobus.. I would appreciate if someone could edit my scheme below to make it work

[Motherboard (MB)] <========= yellow cable ==========> [FAN]

[RHEOBUS-Red] <============ red cable ===========> [FAN]

[RHEOBUS-Black] + [MB] <====== black cable ==========> [FAN]

SebRad · Post by **SebRad** » Mon Feb 28, 2005 2:23 pm

Hi, what you have looks right. Can you put the fan back so its just on the motherboard header and check its all still working? Was it working before?
My board won't recognise <~1500rpm in bios nor in MBM till I adjust the divider (or whatever its called) then can get down to ~1000rpm
Seb

Joe Average · Post by **Joe Average** » Mon Feb 28, 2005 2:30 pm

Yep it works if i just plug in the fan directly to the mb

What setting in the BIOS did U say? something in PC-Health ?

ilh · Post by **ilh** » Mon Feb 28, 2005 2:33 pm

Is the rheobus black at ground or elevated?

Joe Average · Post by **Joe Average** » Mon Feb 28, 2005 2:38 pm

hmm dont understand what U mean by "elevated"

But when ive tried this far with a couple of different alternatives this is what happened:

1. Full fan speed .. controller indicating +7V (i.e. 12V) no RPM
This is when i have the black spiltted to both rheobus and mb

2. Adjustable fan speed ... but no rpm
This is when i cut the black to the mb