# Another computer fan question



## 7843 (Jun 30, 2004)

Hi again. 

I am going to add some various fans to my computer (you may have seen my post about my unexpectedly powerful case fan...), but I'm not sure about the power that I can get from the +12v leads. 

My power supply is a 400W switchmode ATX PSU. It has the usuall connections. However, I have 2 CD drives and 2 hard disks, so all four of the large drive connectors are used, and one of the small ones (for my floppy drive). Connectors in themselves aren't an issue, I can make adapters, however, the power I can get over one lead is an issue. I have posted the table that is on the side of my PSU. My PSU has five sets of leads coming out of it - standard ATX, auxilarly ATX, 2 HD/floppy (remembering that each HD/Floppy thing has two large and one small drive connector on) and one extra connector (with some orange leads and things...) 

in total, therefore, there is 5 yellow (+12v) leads coming out of the PSU. Would these all be connected together inside the PSU? If so, can I load them up until I reach the max current for the 12v supply? Or can each lead take only their 'share' of the total (i.e. total current on 12v divided by 5)? 

On one of the HD/Floppy sets of leads, I have 2 cd drives and one floppy drive. If I also connected a couple of fans to this set of leads, so you think this would cause any problems to the drives? (as long as I was not going above the max current). Which brings me onto my next question. How do I know how much current my various drives draw? 

Thanks, all info and suggestions appreciated 

Tim 

P.S. If this doesn't make much sense, please tell me, and i will re-write it!! (its getting late...)


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## RZA (Sep 24, 2002)

With a 400W PSU, you can run 2 optical drives, a floppy, 2 harddrives, a vid card, a bunch of neon lights, and 4 case fans.

Youget yourself 2 Y adapters and spread apart the load. You'll end up having a few extra connections available for your fans.

I belive the current or power ratings can be found on your drives. A little sticker with serial num, and other info and then power consumption.


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## Worren (Jul 2, 2004)

Since you seem to be a modder how does this sound? Go to a hobby shop and get a 12 volt toy train transformer. Rig up a string of molexes into a power rail and hook it to the dc side. Set the fan voltages to where the noise just gets bad then tuck it away inside. Run the plug through one of the punch outs in back. Sounds crude but it works.


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## Volt-Schwibe (Jan 12, 2003)

i have heard this trick before.

i personally was thinking about doing this myself, but i just put all my fans on a 5v/12v switch using the red 5v and the yellow 12v and a black from one of the power leads as a source.


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## 7843 (Jun 30, 2004)

not bad ideas. I will consider them for future enhancements, however, for the moment I use the 'P4 Power' connection (which I don't need), and I got an extension cable for said connection, and cut one end off, and soldered the ends onto a switch.

I will start running out of plugs soon, and the toy train psu sounds like a good idea, as I have an old one lying around anyway.

Thanks guys

Tim


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