CHFAN2 on 800 G5 SFF Not Working 65w TDP CPU 9700

[blazen2051]

The fans I used to connect to CHFAN2 are indeed 4-pin 12V PWM fans. That's why I'm confused.

When the "increase fan speed when idle" setting in BIOS is set to 0%, the CPU fan works, but the CHFAN2 fans don't rotate.
I tried setting the "increase fan speed when idle" to values greater than 0% and I could hear an obvious speed-up of both CPU fan and the PSU fan, but the fans connected to CHFAN2 still don't work at all.
I also tried adding load to CPU to increase its temp to trigger the cooling, but the CHFAN2 fans are still motionless.
I moved a fan from CHFAN2 to use the CPUFAN, it worked ok. So I'm sure my own fans can function.

I cant trigger the CHFAN2 to turn on even when i stress test the cpu 

[NonSequitur777]

@blazen2051,

The CHFAN2 power/PWM connector should work, and as a matter of fact, once you install a 95-watt and higher TDP processor in your HP EliteDesk 800 G5 SFF as I did in my upgrade project, your system would actually issue a start-up error if you haven't connected a cooling fan to the CHFAN2 connector.

If your CHFAN2 connector is somehow inoperative, no worries, just use a cooling fan splitter cable/PWM fan hub to the CPUFAN connector.  In my experience, these cooling fan connectors can easily handle 2 or 3 cooling fans.

Hope this was helpful.

Kind Regards,

NonSequitur777

[blazen2051]

thanks for the tip i might have to do that. But from what I saw only 1 fan the master fan will be controlled via pwm and rest would be running at full speed. I heard not to exceed 1amp total current per fan header. The CHFAN2 does work but not when i connect a 4 wire fan, but 3 wire fan works fine but @ full speed and its noisy. So im going to install a fan controller and split it for 1x intake and 1x exhaust fan, and control the speed of the fans, so i dont have to buy a whole new set of fans. I'll post pictures once I have all wired up

[NonSequitur777]

@blazen2051,

Yes, the 1amp is indeed an accepted guideline, so, for example: 3 x AVC DA12025B12L 120x120x25mm 4-Pin DC 12V 0.3A PWM or 2 x AVC DS09225R12H 92x92x25mm 4-Pin DC 12V 0.41A PWM Cooling Fans would do just fine.

Kind Regards,

NonSequitur777

[blazen2051]

I got it all wired up, so far running stress test im getting 83C max and 4.55ghz avg. with lid on and intake and exhaust at lowest setting. If i cant keep the temp below 75-80c on the stress test im might have to cut a hole 120mm for the cpu fan