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- 7 Jul 2007
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I thought I'd post this in case anyone else ran into the same problem as me.
I'd bought this 230mm fan to replace a dead case fan, https://www.overclockers.co.uk/bitfenix-spectre-pro-rgb-fan-command-kit-230mm-fg-11b-bx.html, and at first I just couldn't get it to run at anything other than 100%.
I spent about half an hour swapping it to other fan headers with no luck, then disconnected it entirely and tried one of those 7v adapter cables, which seemed to work.
But, as soon as I reconnected the RGB header, it was back to 100%. I then had a quick check with a multimeter, and it turns out the 12V lines from the RGB header and fan headers are shorted together on the fan, so if you plug in both, no fan control settings, bios or otherwise will work, plus it's effectively running the fan from the RBG header, and shorting the RGB header on the mobo to the fan header, which isn't ideal.
In the end I managed to "fix" it by cutting a trace on the PCB which was shorting the two 12V lines together, now it works fine.
I know I could have just run it without the RGB, but it just seemed like such a weird issue. I don't have any other RGB fans, but surely this can't have been intentional by the manufacturer? I wondered if perhaps the same PCB is used for PWM controlled fans, so the constant 12v doesn't affect the speed, but surely shorting the headers on the mobo isn't a great idea anyway.
I'd bought this 230mm fan to replace a dead case fan, https://www.overclockers.co.uk/bitfenix-spectre-pro-rgb-fan-command-kit-230mm-fg-11b-bx.html, and at first I just couldn't get it to run at anything other than 100%.
I spent about half an hour swapping it to other fan headers with no luck, then disconnected it entirely and tried one of those 7v adapter cables, which seemed to work.
But, as soon as I reconnected the RGB header, it was back to 100%. I then had a quick check with a multimeter, and it turns out the 12V lines from the RGB header and fan headers are shorted together on the fan, so if you plug in both, no fan control settings, bios or otherwise will work, plus it's effectively running the fan from the RBG header, and shorting the RGB header on the mobo to the fan header, which isn't ideal.
In the end I managed to "fix" it by cutting a trace on the PCB which was shorting the two 12V lines together, now it works fine.
I know I could have just run it without the RGB, but it just seemed like such a weird issue. I don't have any other RGB fans, but surely this can't have been intentional by the manufacturer? I wondered if perhaps the same PCB is used for PWM controlled fans, so the constant 12v doesn't affect the speed, but surely shorting the headers on the mobo isn't a great idea anyway.