Help with fan module controll

[Ysjoelfir]

Hi everyone!
I recently scored a nice "little" fan module on ebay for one single euro.
It is an Comair Rotron JQ48B0X which was pulled from some unknown unit. I would love to know how to use the various controll wires those puppys have. As I searched through www.comairrotron.com I found a simmilar model named JQ48R7. Even though, the datsheed wasn't really helpfull at all, I could see that the wire colours that were used at my fan array seem to be fairly standard at that producer.
I have the following wires:

red -    supply voltage + 24 - 56 VDC
black -  ground
yellow - "programming wire" -> take a look at http://www.comairrotron.com/different-methods-control-fan-speed
white - part of tachometer output?
blue - part of tachometer output? -> http://www.comairrotron.com/methods-monitoring-fan-performance

I already tried to connect a 1k pot between yellow and black, but whatever resistance I give to that lead, it doesn't make any difference. I am scared giving a voltage directly onto that lead as described at the fan speed controll info page, as the pot-method should have the same effect but didn't work at all.
the white/blue should, as far as I understood, be a single blue/white striped wire, not two seperate? However, I can't get anything out of there at all.
Has anyone an Idea or information about that?
Thanks!

You can find some pictures of the fans attached. Please excuse the bad quality, I didn't find my better camera...

[picandmix]

Typically the fan control wire needs a PWM signal to control it.

As you can see from the screenshot of some other fans from that company, you need a PWM with a frequency around 1k to 10k and with an adjustable duty cycle, with an output voltage around 10v dc.

All you need is a 555 timer , plenty of examples on the web, here is just one, though you need to change the frequency components for 1khz , as the text describes.
http://www.dprg.org/tutorials/2005-11a/

[Ysjoelfir]

Hi picandmix and thank you for your reply!
I should have mentioned that I would like to avoid PWM, but I tried it (using my toellner frequency generator), just to ensure the fan does respond to anything at all. Even though I can't controll the duty cycle using the frequency generator, regarding to the datasheet the fan speed should drop noticably feeding a pure square wave to the controll pin which would be 50% duty cycle. But it doesn't do anything.
Am I missing something?