Electricians!: Need help on re-wiring some fans.

[fleck]

Alright, so as I have mentioned before (I think), I am still using a plain vanilla case from before they even came in black. I have been running it without panels or fans and I finally decided to put it back together. Here it is in all its enemy-to-heat glory:

Alright, so I am now planning on modding old faithful here. Right now she's got one 80MM exhaust fan and it hasn't done anything for temps. There IS a place for an intake fan at the bottom of the front, believe it or not, and that's where me needing wiring help comes in. (Don't worry, I've already thought of modding the cover plate with a grille for [better] flow)

Check out the plug on this old case fan, probably as old or older than the case itself (next to the A64 system that the currently installed fan came from):

WTF is that? Did they even have those plugs in ATX boards? It could also be an old power supply fan, from a busted power supply, like this 120MM fan that came off my old fried PSU:

It's a sexy beast (albeit filthy as All Hell), but once again, THIS one only uses only TWO wires, which is the part that freaks me out, because I'm wondering if I can even make that work with a 3-plug connector.

In case you're wondering, here is the donor of the modern style plug:

Yeah, the one fan that is from back in the K7 days actually has the newer connector. I did briefly think about using it as my GPU HSF, but I'll be moving this 8600 in my non-intensive Linux box soon enough anyway.

Now, I think I get the basics here, but correct me if I'm wrong. On the 80MM fan with the 3 plugs, the colors basically correspond, black, red, (neg, pos), and white would match the yellow. I'm pretty sure I could plug that in and it would work. (I actually had a tech once convert all my fans to molex when a power surge killed my on-board plugs, so I know it has to work, if I have the technique down).

Now my question about the white, or yellow in new fans/molex connectors, is this a ground? I am wondering if I can get away with connecting the 120MM fan to a molex male that I have, but I would have to connect the red to the red, the black to the blacks, and just cap off the yellow?

Thanks in advance for any help or advice!

 

[Nhaz]

the newer fans third wire is most likely the speed monitoring wire.

so likely the black and red are pos neg and the yellow will be the monitoring wire.

 

[fleck]

the newer fans third wire is most likely the speed monitoring wire.

so likely the black and red are pos neg and the yellow will be the monitoring wire.

hey, thanks for the reply. i actually found out red is +12v, black is ground, and the other wire is indeed an RPM wire.

on the 120MM i'm going to connect the black and red to the molex and cap off the rest of the wires on the molex, and on the 80mm it's straight-forward. i got it figured out, thanks man!

 

[rboyer]

Clean those fans with some 409 or something before you throw them in. I have seen many touchscreen games fail due to dirty cooling fans. Just blowing some of the gunk off is worse than leaving it on because an unbalanced cheap chinese fan riding on a nylon bearing is worse than one that had the dust evenly adhered to it over time. As for a grille in the front you would be better off leaving an open hole there because more open space means less for dust to collect on and clog up. Then again you can also mount the fans so that they blow outward and stick a filter on the front of that hole, it won't totally eliminate having to take it apart to clean it every once in a while but if it's the biggest "air leak" in the case then it will catch most of the dust.

 

[mjonesjr]

Get yourself a fan controller and don't worry about re-wiring them. I have one I will sell you for $10 + shipping. It will control 4 fans.

 

[fleck]

Clean those fans with some 409 or something before you throw them in. I have seen many touchscreen games fail due to dirty cooling fans. Just blowing some of the gunk off is worse than leaving it on because an unbalanced cheap chinese fan riding on a nylon bearing is worse than one that had the dust evenly adhered to it over time. As for a grille in the front you would be better off leaving an open hole there because more open space means less for dust to collect on and clog up. Then again you can also mount the fans so that they blow outward and stick a filter on the front of that hole, it won't totally eliminate having to take it apart to clean it every once in a while but if it's the biggest "air leak" in the case then it will catch most of the dust.

There is apparently an idea related to HVAC that can be used on computers, people say that if you have more air blowing in than out it causes a positive pressure system in the case that keeps the dust from accumulating.

 

[fleck]

Get yourself a fan controller and don't worry about re-wiring them. I have one I will sell you for $10 + shipping. It will control 4 fans.

Nahhh, the whole point of resurrecting these two fans is not to spend any money. You've already seen I roll the Plain Vanilla way so I don't want or even need a controller, don't wanna mess with it. But thanks.

 

[mjonesjr]

There is apparently an idea related to HVAC that can be used on computers, people say that if you have more air blowing in than out it causes a positive pressure system in the case that keeps the dust from accumulating.

That is true. If you have more air incoming into the case, then it will create positive pressure. Thus eliminating the formation of dust.

I have 1x 140mm exhaust fan, 3x 240mm & 1x 120mm (soon to be 2x 120mm) intake fans. Than I also have my 120mm heat sink fan for the CPU and a 60mm fan on the video card. I NEVER have dust in my case.


Here is a link you may find interesting.
http://www.hardwaresecrets.com/article/496

 

[rboyer]

There is apparently an idea related to HVAC that can be used on computers, people say that if you have more air blowing in than out it causes a positive pressure system in the case that keeps the dust from accumulating.

Yeah I forgot that he's dealing with an old ass case. I'm used to working with sealed commercial applications with aluminum air filters. And that positive pressure system works but is not a guideline or anything because not everyone designs things that way.

 

[Wicked_Sludge]

i dont know about you guys, but all my dust comes FROM my cooling fans. meaning it cakes up on intakes and parts (namely my hard drives) facing the output of the case intake fan.

 

[mjonesjr]

i dont know about you guys, but all my dust comes FROM my cooling fans. meaning it cakes up on intakes and parts (namely my hard drives) facing the output of the case intake fan.

That is because you are drawing out more air than you are putting in. Check to make sure that you don't have more than the fan on the back of the PC as an exhaust fan.

 

[Wicked_Sludge]

my power supply has 2 fans that act as exhaust fans for the case. my CPU fan also acts as an exhaust fan.

i see how having positive case pressure would keep dust from getting in through grates and seams. but no matter how much case pressure you have, your intake fan(s) are drawing air...and any dust floating in it...in. how is positive case pressure supposed to prevent that?

 

[mjonesjr]

my power supply has 2 fans that act as exhaust fans for the case. my CPU fan also acts as an exhaust fan.

i see how having positive case pressure would keep dust from getting in through grates and seams. but no matter how much case pressure you have, your intake fan(s) are drawing air...and any dust floating in it...in. how is positive case pressure supposed to prevent that?

All of my intake fans if you put your hand up to them feel like they are blowing air out. That is how they don't draw in dust.

If I were you, since the power supply is acting like an exhaust fan (drawing air from within the case and blowing it out) I would turn the actual exhaust fan on the back of the case to make it another intake fan.

My PSU is a bottom mount unit, so it is drawing air from outside the case and blowing it out of the PSU outside the case.

 

[Wicked_Sludge]

lets look at my girlfriends newer dimension desktop. the case is assembled "backwards", so the CPU is toward the front. the CPU fan acts as an intake fan that blows accross the CPU then into the case. the only exhaust fan is a much smaller PSU fan. this case should have positive pressure (maybe not much). the CPU heat sink collects dust like mad due to the intake fan blowing air accross it.

as long as your intake fans are...intaking....they suck in any dust floating around in the air as well. thats just been my experience. admittedly, i havnt owned a lot of cumpters in my life (4).

the exhaust fan on my pc doubles as a CPU fan (it has fancy ducting on it). id hate to flip it around since i know pulling air is a more effective method of cooling than pushing it (not that i have cooling problems).

 

[mjonesjr]

That is a problem with all factory built PC's; they draw in dust like made because they do not have proper intake cooling. My Dell Dimension 9200 I have at work draws in dust like crazy because of the 2 fans it has (1 intake fan, and one exhaust/CPU fan) along with the exhaust fan the PSU has.

Here is some reading for you:
http://www.tomshardware.com/forum/238184-31-case-airflow-positive-negative-pressure
http://www.xoxide.com/computer-cooling.html

Here is a good positive vs. negative pressure video:
http://www.youtube.com/watch?v=Qe-2ZqmSGug