I recently installed an Aquaero 6 Pro USB to control the fans in my main computer. The Aquaero 6 seems to be working normally. I then tried to add the passive heatsink to the controller, but this causes a loud hissing sound. This can be heard when the power is on, but before the computer starts up. It can also be heard after the computer starts up. When I remove the passive heatsink the noise disappears. I have checked the positioning of the thermal pads, and the passive heatsink. Each time I put the heatsink onto the controller the noise appears, and it disappears when I remove the heatsink.

I was wondering if anyone had any ideas about how to fix this problem. Many thanks in advance.

Hi Shoggy

Thanks for the reply. Sorry it took so long for me to respond, but I've been away on business and holidays. I take it the resistor you want me to remove is the one circled in red on the image below?

https://1drv.ms/i/s!An_Ro27ONKbOfpIsPjqlYFIPdjU

Update.

I removed the resistor as you suggested and re-fitted the heatsink. The hissing sound has completely disappeared, and the Aquaero controller appears to be working perfectly.

Many thanks for your help with solving this problem.