Antminer S9 autofreq fan speed override only working on one fan?

[myholdout]

As you may know, Bitmain is switching over to an auto-benchmarking/calibration model without any fan speed controls.  I just received a 14 TH/s S9 with auto-freq firmware installed (previously this speed model was fixed frequency).  I added the following to bmminer.conf:

"bitmain-fan-ctrl" : true,
"bitmain-fan-pwm" : "40",

Kernel log shows:
Set fixed fan speed=40
FAN PWM: 40

However it appears to only have affected the speed of the secondary fan (Fan6) while the primary fan (Fan3) is still on auto-speed.

Thoughts?

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[fanatic26]

The only thought is why are you screwing with the fans? The auto sensing firmware will run them as needed, you shouldnt be messing with it.

[fanatic26]

The auto frequency boards are different than the old fixed frequency so you cant use the old firmware.

Again I state, the software controls the fans for a reason, you should not be messing with the fan speeds.

[the_electronrancher]

It's not a very well built firmware - it also ignores a fixed frequency setting in the same file.  It's strange that it accepts your setting for one fan, but chalk it up to implementation issues.

Fanatic is right though, messing with the fans will not down clock the device - it will just run at the same power with poor cooling, meaning a shortened lifetime for your chips.

Take the suggestion and delete the configuration mods, let the fans run at the speed needed to properly cool the device.