7v case fan mod = higher 12v rails?

hydroponik

Senior member
Oct 2, 2006
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I just replaced a 120mm thermaltake fan with an identical one I had in storage, however I totally forgot I did a 7v mod on my old (broken) fan.

When I started up the new one, my reported 12v rail said something like 11.8, however when I modded back to 7v due to the noise, the 12v rail went up to 12.9. I thought it was supposed to be the other way around?
 

EarthwormJim

Diamond Member
Oct 15, 2003
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Usually the 3.3 and 5v rails are created from the 12v rail now days. Maybe the dc/dc converter (or regulator, not sure what's used) for the 5v didn't like having current fed into it's output and messed with the 12v system?


Where were these readings taken from? If it's from software, there is a HUGE margin of error from where your motherboards measures voltages.
 
Jun 14, 2010
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Get a Voltage control IC 7806 it will reduce the supply voltage from 12v to 6v and you can connect the fan to 12v line.

It's a small IC with three legs. one is +ve input, second is comman ground or -ve and the third one is +ve output.
 

EarthwormJim

Diamond Member
Oct 15, 2003
3,239
0
76
Get a Voltage control IC 7806 it will reduce the supply voltage from 12v to 6v and you can connect the fan to 12v line.

It's a small IC with three legs. one is +ve input, second is comman ground or -ve and the third one is +ve output.

Yes a regulator is a good idea. It's amazing how handy the 78xx series is.
 

hydroponik

Senior member
Oct 2, 2006
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The readings were from software, I know it won't be 100% accurate, but it seemed weird to me that the voltage would be stronger after doing this mod.

Oh well, I don't think it's a huge issue as my system is still stable, I was just curious.