The front case fan on our 1600SC died and replacement seems to be extreamly pricy ($100+ on ebay)

It appears to be a fairly run of the mill 120mm x 38mm dc fan but a couple of weird things I have a question about.

The connector seems to be odd. While it is a 3 pin connector, it has a weird key/interlock on it that I cannot find on any 'generic' replacement fans. So, I was gonna just lop off the old connector and hook it to a new 'off the shelf' fan. That brings me to this:

The wires are red/white/black in the connector. Red/black are easy but the white is what I am concerned about. It is my understanding that this is usually a signal to report rpm on but I am wondering about this fan. It is a JMC/DATECH 1238-12BHTA and I have read some pdf's that indicate the white wire is for 'PWM' (see here http://www.jmcproducts.com/product [...] 12_PWM.pdf ) so I am wondering, can I just use an off-the-shelf red/black/yellow wire fan and hook it up to the red/black/white wire connector of this JMC fan? Whadda ya think?

thanks
don