[SOLVED] Case fans sometimes stuck at 100% on startup/wake

[Platinum_Gamer]

Hi, my specs are:
ASRock Z370m Pro4 mobo
Be Quiet 802 case
3x 140mm Pure Wing 2 (3 pin) fans

Currently I have all 3 case fans attached to a splitter which is attached to CHA_FAN1. I moved it there about a week ago when I was playing around with my fan setup and cable management.

However, now sometimes on boot or wake, the fans would spin at 100% and won't change even when using ASRock's A-Tuning software. The temps are not high enough to hit the 100% speeds as this normally happens on cold start. To fix, I'd need to put my PC to 'Sleep' and wake it up. It'll work sometimes. A full restart never fixes the problem.

I have unplugged and re-plugged it into CHA_FAN1. The connections look fine to me.

Anyone know why it only happens sometimes? Should I move it back to CHA_FAN2 which was my setup before?

 

[lvt]

Do both CHA_FAN1 and CHA_FAN2 have 4-pin connectors?

 

[Paperdoc]

Those are 3-pin fans. MOST mobo fan headers with 4 pins can be configured correctly for either 3-pin or 4-pin fans. But also they often have an "auto" setting which attempts to test what fan type is connected and make its own adjustment. That auto system may be making errors.

First. check again the connections of your fans to the Splitter. On the Splitter there will be only ONE output with all four pins. You MUST connect one of your fans to that one output so its speed signal can be sent back to the mobo host header.

Go into BIOS Setup - see mobo manual p. 72. Select the fan header you are using. Look for an option to set the header MODE to either PWM or Voltage (aka DC Mode) and set to DC Mode. Then check that header's Temp Source and ensure it is set to Motherboard, not CPU. Use Esc to get back to the main Monitor Menu (p. 72) and click on EXIT at upper right. See p. 78. Choose Save Changes and Exit to save and reboot.

 

[Platinum_Gamer]

Those are 3-pin fans. MOST mobo fan headers with 4 pins can be configured correctly for either 3-pin or 4-pin fans. But also they often have an "auto" setting which attempts to test what fan type is connected and make its own adjustment. That auto system may be making errors.

First. check again the connections of your fans to the Splitter. On the Splitter there will be only ONE output with all four pins. You MUST connect one of your fans to that one output so its speed signal can be sent back to the mobo host header.

Go into BIOS Setup - see mobo manual p. 72. Select the fan header you are using. Look for an option to set the header MODE to either PWM or Voltage (aka DC Mode) and set to DC Mode. Then check that header's Temp Source and ensure it is set to Motherboard, not CPU. Use Esc to get back to the main Monitor Menu (p. 72) and click on EXIT at upper right. See p. 78. Choose Save Changes and Exit to save and reboot.

My CHA_FAN headers are unusual. They are 4 pin but none of them support PWM and there is no Auto setting in the Motherboard or a setting to switch PWM<>Voltage. They are only voltage controlled.

My splitter (should've pasted this earlier) is https://www.amazon.com.au/gp/product/B08MVPLMW2/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1, 4-pin input to three 4-pin outputs. I'll double check all the output connections again but they should be all be solid.

I'll double check my BIOS again but CHA_FAN1 should be watching Motherboard temps atm.

Think that header could be faulty?

Edit: I've taken a look inside again, see nothing wrong with the header or connectors. Switched it back to CHA_FAN2 and see what happens