Unable to post if 4 pin case fan is connected to board

[Cobalt1704]

System will post, but only if the 4 pin case fan connector is not attached to the motherboard. It boots fine if the fans are connected to the PSU etc., as long as they are not connected to the board. Advice?

 

[Lutfij]

Can you please list your specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

Have you tried disassembling and reassembling outside of chassis with the assumed culprit chassis fan plugged in? Speaking of chassis fan, what fan are we talking about? Perhaps a picture of the fan should help. One other point, are you referring to the 4pin molex connector or a 4pin PWM connector?

 

[Cobalt1704]

Can you please list your specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

Have you tried disassembling and reassembling outside of chassis with the assumed culprit chassis fan plugged in? Speaking of chassis fan, what fan are we talking about? Perhaps a picture of the fan should help. One other point, are you referring to the 4pin molex connector or a 4pin PWM connector?

CPU: AMD FX-9590
Cooler: Fractal Celsius s36
Motherboard: Asrock 990fx extreme9
Ram: 16GB Crucial Ballistix
SSD: 120GB Sata II Generic Micron
GPU: Zotac GTX 960
PSU: EVGA 750G1
Chassis: Thermaltake Suppressor F51
OS: Win 10 Pro

Haven't tried breadboarding it again yet, the issue came up after two weeks of normal operation. The 4 pin connector I'm referring to is the PWM connector. With it attached, the system won't post, without it everything else boots fine. But without any case fans running I doubt it would run long before overheating.

One case fan is a 4 pin PWM, the others are all three pins. The two PSU cables I have: one is a 4 pin molex connector with three headers, the other is the same but with one of the 4 pin molex being a 4 pin PWM connector. That's the one I'm trying to use, the other one works fine. It seems that the motherboard doesn't like the cable with the PWM connector.