I picked up some Delta TCF1212DE as I've been having trouble keeping GPU temps under control even with three EK Vardar (the 3k rpm ones). I wired the new fans so that only the RPM and PWM signal is coming from the mainboard (Asus ProArt X570 WiFi Creator), the power and ground are connected to a dedicated PCIE power supply cable since these fans are 3.9A each, well above the roughly 1.2A that my mainboard is capable of driving on each of it's fan headers.
The fans start and run, but speed control is inverted - i.e. if I set them to 100% they stop, and if I set them to 0% they go into their 6,000rpm jet engine mode. Unfortunately, since Asus' software doesn't allow me to just make a reverse/inverted fan curve, and since SpeedFan (which supposedly has an option to invert PWM logic) doesn't seem to recognize any fan controls on this mainboard, I'm worried that my only option is going to be to resort to building a 74HC logic inverter as suggested on the EE stack exchange... But the PCB and BOM cost for even a small project like that can easily reach a hundred or more dollars, and it'd be just to fix something that I should be able to do by flipping a bit somewhere in the BIOS or SMC firmware or something... I just need to figure out where!
As I'm aware, this style of PWM is more common with industrial equipment, but it seems like it's perfectly electrically compliant, so I really do suspect this should be doable in the BIOS... just a "Invert PWM logic" checkbox or something!
Anyone run into this before or have any suggestions?