PWN failing on two fans?

Bazippy · 25 Jan 2020 at 22:34

So messing with my fans ive noticed highish temps on my aio cpu cooler. Messed around with settings and realized the fan speed of these were stuck at about 600rpm. Using Argus monitor.
Went into bios to manually up them to full speed which did its job. Back in windows and they are now stuck full speed. all other fans working normal and controlled by Argus. Swapped my spare pwm fan to the cpu header and it was controllable. same software, same cpu header.
Back in bios moved the fan headers to DC from PWM on the two affected fans and they are controllable in windows again with arus monitor. Is this a thing?

Maximus hero maximus hero viii
The fans are Noiseblocker Silent Pro PWM 120mm

EsaT · 26 Jan 2020 at 11:08

Have you tried those fans one at time?
If they work well with PWM that way, mobo might struggle to properly pull PWM signal to ground with two fans.

Bazippy · 26 Jan 2020 at 12:10

They are on separate headers. One is cpu one is next to it can't remember it's name. They work as one. Adding a different pwm fan to the second header gives control to the new fan only. It's bizarre working lovely in DC mode. It looks if I changed the fans I'd get normal pwm control. It's as if the pwm module on both fans has died.

doyll · 26 Jan 2020 at 14:34

What Esat said

Strange problem. Normally a header can PWM control 7-10 fans .. part of reason PWM splitter hubs only have 8 headers.

Maybe try controlling them with variable voltage?

Bazippy · 26 Jan 2020 at 16:58

doyll said:
What Esat said

Strange problem. Normally a header can PWM control 7-10 fans .. part of reason PWM splitter hubs only have 8 headers.

Maybe try controlling them with variable voltage?

Got control over them fine, on the asus board in bios you can change from pwm to dc. That gave me back normal control. Just no idea how a fan can fail at pwm but still work. Anyway pc is running like a chilly dream now

doyll · 26 Jan 2020 at 18:24

Bazippy said:
Got control over them fine, on the asus board in bios you can change from pwm to dc. That gave me back normal control. Just no idea how a fan can fail at pwm but still work. Anyway pc is running like a chilly dream now

Motherboard PWM control is not working as it should .. in other words it's defective. You could exchange motherboard, but might have similar problem with replacement.