bought 12v - 9v cable, now fan is all screwy

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FearTheCow

Supreme [H]ardness
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May 2, 2006
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I bought a cable to run my scythe S-flex fan at 9v instead of 12v. I plugged it into my MB and the fan started up fine, then stopped spinning and the middle of the cable got war/hot. I unpluugged from MB and plugged the fan/adapter into a molex connector, the fan started/ran fine except an annoying ticking noise. I unplugged the 12v-9v cable and plugged the fan back into the MB, the fan now pulses, it literally looks like it is getting juice for about 2-3 seconds then isnt for 2-3 seconds, anyone have an idea what happened and what I can try to fix this? The pulsing happens whether I use the MB or a molex connector. I really hope the fan isnt jacked up, freaking thing was $20 and I only got it a week ago :(

Cable I bought - http://www.jab-tech.com/12v-to-9v-Cable-pr-2040.html
 
I would never use a cable like that especially on a motherboard. With the temperature controled voltage ramps that you can control (including max speed percentage) I really don't see a need for that.

For lower voltage, I have always used the +12 and the +5 as the ground to get 7V. Have an old system with a fanbus and the fans ran at 7V all the time. With the new motherboards being able to lower the speed at idle temps for the HSF and the quieter 120mm fans in the case, I have no need for the fanbus in this system.

It looks like that cable is dropping voltage using a resistor or something (whatever is under the shrink wrap) and whatever resistor it was using probably fried and took out your motherboard fan controller.

I never trust mystery cables.
 
What Paragon said. If you want to run the fan slower, just make your own cable that swaps out the +5V and the ground wires so the fan will run at 7V - and then hook that up to a power supply molex, not a motherboard header. Have you tried the fan directly hooked to a molex? At least would tell you if it is the fan or the MB header.
 
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