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Maximus V Gene - Fan header 1, low voltage

adam2104
Level 7
Anyone else having trouble with the chassis_fan1 connector? My connector is putting out 3v LESS than the other connectors. For example:

With fan control enabled in the BIOS and set to the "Standard" profile:
chassis_fan1 reads 5v
chassis_fan2 reads 8v
chassis_fan3 reads 8v

With fan control DISABLED in the BIOS, after a reboot:
chassis_fan1 reads 9v
chassis_fan2 reads 12v
chassis_fan3 reads 12v

Because of this my fans are running wonky. Anyone else see this issue? Ideas on how to resolve?
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18 REPLIES 18

Spathi wrote:
You may want to check it has not done something unexpected. It is obvious that the CPU header voltage/pulse commands are being directed to some or all chassis fans as well.


Check what now?

The fan headers should be 12v. At the very least, all the fan headers should put out the same voltage. They should be consistent. I have four PWM fans in my machine, one on the CPU, and three on the case. In actuality which fan I connect doesn't matter, chassis_fan1 is always reading several volts lower than the other headers, even if I disable all motherboard control.

responses very good! )

Shamino
Moderator
the new bios i have verified its 12v when disabled fyi

Shamino wrote:
the new bios i have verified its 12v when disabled fyi

When will this new BIOS be released?

I am having the same issue using bios 0903.

Disabling q-fan for chassis fan 1-3, but not for CPU, will give the results 9v, 12v, 12v.

However, also disabling q-fan for CPU fan will give 12v, 12v, 12v as expected for chassis fan 1-3.

Unfortunately, even with q-fan for CPU and chassis fan 1-3 disabled, I am not able to get Fan Xpert 2 to work properly, it will give the result 9v, 12v and 12v on the chassis fan.

As a matter of fact, when the CPU load goes up, the voltage on chassis fan 1 will increase too, up to 12v.

Is this something that will be fixed in a future bios update?

MathWiz wrote:
I am having the same issue using bios 0903.

Disabling q-fan for chassis fan 1-3, but not for CPU, will give the results 9v, 12v, 12v.

However, also disabling q-fan for CPU fan will give 12v, 12v, 12v as expected for chassis fan 1-3.

Unfortunately, even with q-fan for CPU and chassis fan 1-3 disabled, I am not able to get Fan Xpert 2 to work properly, it will give the result 9v, 12v and 12v on the chassis fan.


Select RPM fix mode and set max value for CPU fan on Fan Xpert 2, and you will get 12V for fan 1.
Voltage level on fan 1 behaves as it is switched by PWM signal for CPU fan.
I'm afraid this is not a software issue but a hardware issue.
I've tried latest bios 1101 but issue still remains.

In fact sth is completely wrong with CHA_FAN_1:

10732

Fan min RPM is 579 (c.a. 45% of max), whereas controllable range is 90-100% 😞

Two identical fans on CHA_FAN_1 and CHA_FAN_2 work with two completely different characteristics 😞

Bios 1101.

M.

adam2104
Level 7
Its annoying for sure. I don't understand why one header is different from the rest. Fan headers should be 12v, not 3v lower than the other two. Nothing in the manual describes this behavior. Sounds like a bug to me.

adam2104
Level 7
Yep. That's the same thing I see, two identical fans. I stopped using chassis_fan_1. It's broken.