I have a bunch of fans that I removed from a Cisco switch we were dumping. Fan is a SUNON PSD1204PPBX-A. Specs: 12 VDC, 12.2 W
I tried Googling for the pin-out assignments, but could not find one. So, I'm using the process of deduction. There are a total of eight pins on the connector. The fan is actually two fans in one, so I'm sure each fan is a typical 4-wire fan. However, unlike 4-wire fans used in PCs, the colors on my fan don't match up.
Checking continuity first, pins 1 and 5 are on the same network, as well as pins 4 and 8. Based on the color of the wires, I'm guessing that pins 1 and 5 are Control (pin 1 is RED,) and pins 4 and 8 are GND.
Next, pins 3 and 7 are also on the same network. My guess is that these pins are 12VDC. The remaining pins are 2 and 6, and each pin has its own network, therefore my guess is this is the SENSE signal, as the switch is capable of detecting a bad fan.
So in summary:
1, 5 - Control
2 - SENSE for fan #1
3, 7 - 12VDC
4, 8 - GND
5 - SENSE for fan #2
Am I correct?