Mellanox InfiniBand SX6018 - Switch - EMC only - $300 OBO

Got 4xNoctua NF-A4x20 and replaced 4 super noisy stock fans out of HELL.
Default pinout is as follows (you 're looking at terminals, with two smaller hooks facing down, holes facing away):
1.Red +12v
2.Blue Tachometer(RPM)
3.Yellow PWM
4.Black GND

I've unmounted stock fan block, removed wires from white connectors, removed black connectors from Noctua fans, connected wires as above. Below is Noctua color wiring, same layout
1.Yellow +12v
2.Green RPM
3.Blue PWM
4.Black GND

After connecting all of them to board PWM takes effect (without active alarms fans go from ~20% to ~40% in cycles, which makes it unbearable). Even with Noctua low-noise adapter (which kinda makes cycles smoother) it was more irritating that running with 100% speed.
So, I removed PWM wire from each connector. System detects all fans, but can't control them, and it's really quiet!
So, my advice would be to get 3-pin fans and wire them the same way so you would know if one of them really fails.
It's probably not possible to control fans from PPC board, tc daemon just reads data there.

If that helped, please endorse: https://goo.gl/RfjbnG

 

Since this thread had a little more fan-mod talk than the Beware of EMC switches sold as Mellanox SX6XXX on eBay thread I thought I'd ask here. Does anyone know what the slowest fan RPMs the SX6012 will tolerate without alarm?

edit:
About 2 months after this original post I swapped out the two Yate Loon D80SM-12 80mm fans I modded piggyback style on the switch for two Sanyo 9S0812P4F01 fans. I split the tach lead to two headers each; so the switch reads it like the two fans are four. These fans are PMW, 2800 RPM and reading 2600 - 2700ish in MLNX-OS. No fan alarms with this setup and CPU_BOARD_MONITOR2 temps in the low 60s.

 

did you found the slowset fan RPMs?
at least delta efb0412hhd 8200rpm 9.43cfm 0.15amp pwm fan is not enough, first it will set 60% after boot up,then it will 40% 100% and then 40% 100% loops(in sx6012 log )
after I cut pwm wire. everything is ok , fan light remain green , no alerts messages . The temperature is 5 degrees higher than origin fan.
Will try 9200rpm 11000rpm pwm 13000 rpm fan if I have time