Super wild arse guess - pin-outs for a 4-wire fan - Page 1
Forum section: electronics / beginners

author: groinksan
author_rank: Contributor
timestamp: February 01, 2020, 09:43:41 pm
content: 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 WI 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 isRED,) 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, based on the assumptionYELLOWusually means 12VDC in power supplies, and it is next to GND. 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 - Control2 - SENSE for fan #13, 7 - 12VDC4, 8 - GND6 - SENSE for fan #2Am I correct?

author: jceev
author_rank: Newbie
timestamp: February 01, 2020, 10:29:43 pm
content: Just an idea, but since you have the circuit board that the fan connector is attached to, can you determine (at least) power and ground by looking at the board layout? A lot of times the Cisco gear has PWM controlled fans to adjust airflow, so it may not be that easy...

author: groinksan
author_rank: Contributor
timestamp: February 01, 2020, 10:43:40 pm
content: That would be a good idea. Unfortunately, the board has zero discrete components and chips on it. The PCB also has an edge connector that slips into a slot on the switch - 34 fingers total, and looks somewhat like a mini PCI edge connector. Pins 4 and 8 do connect to the ground plane, particularly the copper around the mounting holes of the PCB. Pins 3 and 7 connect to six fingers on the edge connector, and there is a large plane for this network, which is why I would guess it is the 12VDC network. All the other pins have very fine traces to the edge connector, so I presume they're simply for signaling.

author: Jwillis
author_rank: Super Contributor
timestamp: February 02, 2020, 12:56:44 am
content: You should be able to separate each fan into 2 banks of 4 wires. Looking a the board theirs a consistency to the traces from left to right . Left 4 wires is one bank , Right 4 wires is second bank. Second bank has Red and black which are standard positive negative . So looking back at the first bank orange and grey are positive and negative. The second bank looks like a standard 4 wire with red blue yellow black. Standard 4 wire is Red (Pos) Black (Neg) Yellow (Sense) Blue (Con). Looking back at the first bank White (sense) ,Green(Con)This is the best guess I could come up with.

author: nonyhaha
author_rank: Newbie
timestamp: May 19, 2020, 05:39:17 am
content: Hello everybody,I was also looking to find out more details about this double fan.What I can tell you in my case is that my version of the fan has the pins alternating. 1-3-5-7 is on fan 1, 2-4-6-8 is on fan 2.

author: opensourcefan
author_rank: Contributor
timestamp: November 07, 2022, 04:43:37 pm
content: I found this thread when searching for the pinout of my fans. Some of the information isn't correct.The correct pinouts, discovered by scoping is as follows:The fan configuration and connector may be different but the wire colors appear to be consistent for the SUNON PSD1204PPBX-A model.12V - red and orangeGND - black and greyCONT (pwm) - yellow and whiteSENSE (tach) - blue and greenMy setup shown below has 2 sets of fans per connector for a total of 4 fans. Mine has the CONT yellow and white ganged together with the SENSE blue and green isolated to detect a single fan fail.