I'm putting together my first PC and have run into another problem. My liquid cooler is installed and working, but the four fans in my Sama S40 case won't spin. The fan hub has a dangling cable labeled PWM, and I was told it may also need SATA power from the PSU. However, I can't find a SATA power connector anywhere on my Raidmax AED 850W non-modular power supply or among the cables in the case. My motherboard is a B850M Eagle Wi-Fi 6E. I connected one case fan directly to a SYS_FAN header and it spun, so the fans work. How can I power the hub?
2 Answers
The PWM lead from the hub is mainly for sending fan-speed control and possibly tachometer information to the motherboard. It usually isn’t enough to power all the fans. Look through every fixed cable bundle coming from the non-modular PSU, especially behind the motherboard tray and near the drive bays, for a wide, flat SATA power plug. It may be tucked away or connected to another SATA plug in a chain. Don’t connect it to a motherboard SATA data port. If you still can’t find one, check the PSU’s exact cable layout or contact the manufacturer before using an adapter. For now, you can run the case fans from the motherboard’s SYS_FAN or CHA_FAN headers, as long as you don’t exceed the header’s combined current limit.
The liquid cooler isn’t the source of this issue. Its pump and radiator fans use their own PWM connections, with the lighting connected separately if applicable. The four case fans are controlled by the case fan hub, so that hub needs its own power connection in addition to the PWM cable. Trace the hub’s cables carefully and check whether its power lead is hidden behind the motherboard or already connected to a PSU cable. If the hub has no SATA or Molex power lead at all, it may be a hub that expects power through a motherboard fan header, in which case its manual or model label should confirm that.
The cooler is connected and working normally. My problem is only with the four fans mounted in the case.
I bought the PSU used and didn’t receive a manual. I tested one of the case fans on a SYS_FAN header and it spun, so the fans themselves are fine. It looks like the hub is the part that isn’t receiving power.