3 pin fan connectors ?

April 1, 2008 at 06:09:43
Specs: WinXP Pro SP2, 2.8G.B. Dual Core 3 G.B.
I purchased and installed a EasyWatch fan controller monitor and temp monitor that fits into any 3.5" bay at the front of your PC Tower .Since I had two of these 3.5" bays at the front on my PC empty and the easywatch shows you the information in a lite LCD display I figured it would be a nice addition to my PC . It does dress up the front panel ,my problem is the three fan monitor 3 pin male connectors will not fit into any of the fans 3 pin female ends inside my case so that I can get the RPM reading on the EasyWatch ? The temp monitor sensor's are all in place and Iam getting raadings on the temps however the fan display is only giving me a series of zero's because I cannot connect the fans to the EasyWatch by Aerocool ? Anyone have any suggetions ,I even tried opening up the plastic cover on the male ends and still no joy ? Any suggestions or links to a site with some kind of adapter would be greatly appreciated !
Thanks Nick

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April 1, 2008 at 12:21:52
The connectors from the EasyWatch are male for a reason.
You do not plug the EasyWatch into the male pins on the mboard headers. You plug the 3 wire female connector from fans into the male connectors from the EasyWatch. The CPU fan must be connected to the CPU fan header; you can't plug it into the EasyWatch unless you can find a Y cable so you can connect both. It is meant to monitor case fans, or a PS fan.
The EasyWatch wiring provides the power to the fans through it's wiring and two of the three connections to each fan - you don't need to connect the fans other than the cpu fan to the mboard.

If you were to connect only the EasyWatch to the mboard headers you would get zero rpm and you might damage the mboard or the EasyWatch - two of the 3 pins on the header are powered - it's the fans that produce the rpm output it reads, not the mboard.

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April 2, 2008 at 06:58:18
Thank you for yor reply and info reguarding my post on the EasyWatch ! Iam aware that the connectors on the M.B. are male pins that supply power to the fans ! The problem is when I unplug them the male connectors from the EasyWatch 3 pin male plugs will not fit over the 3 pin female dell supplied plugs ? I even tried opening up the plastic cover on the easywatch male plugs and still could not get the pins to plug into the female fan connector ? If Iam to use a Y adapter then the EasyWatch would not be able to show the 2 readings off one connector ,they supply 3-3 pin male plugs and the display has RPM1,2 & 3 ! They must be plugged in seperatly in order to get 3 readings from 3 differant fans .One fan I installed a slot fan called a System Blower a exhuast fan that helps pull hot air out of the tower would'nt you know it has a four pin connection the P.S.U. has extra's available ,so I cannot monitor that one! Iam woundering if I can bypass the plugs and splice the wiring together ? Again thanks for your reply ,still would aprreciate any info on hooking up fan connections and work arounds when the OEM plugs and a accesssory's do not match up ?
Take Care Nick

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April 2, 2008 at 13:03:58
I took a look at the info for the Dell XPS400 series.

I had assumed Dell wasn't pulling it's proprietary crap anymore, outside of maybe the PS and case fittings, or custom optical drive fronts, but apparently they still are. This model series at the very least has an oddball mboard, and an oddball PS.

support docs

I looked at both the HTML service manual and the PDF owners manual.
It seems it has two fans mounted vertically connected via proprietary cables with oddball end connectors, and the two fan headers on the mboard may be much larger than standard ones.
There is absolutely no info about what the pinouts of the headers are (what each pin is for).

As I said above, some headers for the cpu fan have 4 pins - the fourth pin is for reducing the cpu speed under certain conditions - in that case, if the fan has three wires, on a standard mboard, a standard 3 pin hole female fan connector can sometimes go on in either of 2 positions on the 4 pins - one position works, the other does not.

"One fan I installed a slot fan called a System Blower a exhuast fan that helps pull hot air out of the tower would'nt you know it has a four pin connection"

Sounds like that was meant to be plugged into a standard 4 pin cpu fan header that some recent mboards have.
3 in a row of the 4 wires are wired exactly the same as for 3 wire fans. That should work fine with the Easywatch 3 pin connector if you plug into the right 3 pin holes in a row.

There is insufficient info in these manuals, so I cannot tell you how to hook up the oddball end connectors from the fans, and I cannot tell you if the fan cables have their wires in the standard pattern or not. The only thing I can suggest is for you to look on the mboard near the headers to see if there is labelling next to the pins - e.g. + and - for power, r? or something else for rpm.

The 3 male pins on each connector from the EasyWatch are probably arranged and wired in the standard pattern, and they fit onto a standard female connector for a 3 wire fan only one way - the pin holes are closer to one side.
power + polarity is in the middle, the wire color might be red; power - polarity (power ground, also serves as rpm ground) is on one end, the wire color might be black; rpm is on the other end, the wire color might be yellow, or some other color not black or red.

If you can't confirm what pin on the mboard header is for what, or what wire from the fans is for what, you risk damaging something if you splice the wires from the fans to the EasyWatch.
You can get standard 3 position female connectors (the holes are spaced at 1/10" , .10", intervals) from places that have electronic part and install them on the fan wires yourself, but you have to be able to determine what each wire is for.
AND as I said previously, the cpu fan MUST be connected to the mboard header.

On second thought using a Y wiring arrangement to connect the cpu fan to both the EasyWatch and the mboard header could also damage the mboard circuits and the Easy Watch circuits - two pins on the EasyWatch male 3 pin connectors are powered from the EasyWatch wiring AND two pins on the header are powered - connecting the Y wiring may cause a short! (although sometimes you don't have that problem with low voltage DC circuits)

If you don't want to take the risk of messing with any of that, you may be able to install a standard case fan inside the case somewhere and monitor that with the EasyWatch.


The EasyWatch would hook up fine if the system had a standard mboard with standard fan headers and the system had standard fan connectors from the fans (they've been the same since at least the mid 90's). You take the chance you're going to run into this proprietary crap when you buy a Dell system.
As far as I know, other brand name systems do not have this problem, except possibly for models that have special server mboards. At least, HP and Compaq have not used other than standard mboards for a long, long time.

Most brand name system builders DO NOT make the mboards in their models - they are supplied to them by major mboard manufacturers.
Look on the mboard for an obvious model number printed on it in larger characters, often between the slots or near the center of the mboard. If you find that there may be other places where the pinouts for the fan headers can be looked up, etc. On the other hand, this oddball mboard may not have that.

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April 3, 2008 at 05:58:06
Hi Tubesandwires,
I want to thank you for the wealth of information ou provided me ! I think I will play it safe and not mess with the fans with the oddball connectors. Your are certainly correct that this is a Del board ,right under model # it says system board >Dell Inc.! Now the system blower I installed onlt cost me twn dollars so if I was to mess it up trying to change the connector or find a 3 wire to four wire adapter. However the extra exhaust poer it gives my system is significiant and I hate to destrot it .In the end I believe leaving well enough alone is best ,I can live wwithout knowing what RPM the fans are spinning at. The temp monitors are all giving me readings ,as we speak my CPU is at 46C the VGA 38C and overall temp inside case is 32C ! Again thank alot for your info ,Iam going to copy your reply and then get out my owners manual and see what info it supplies me on the fan connections ? Your time and knowledge is greatly appreciated !
Take Care Nick

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April 3, 2008 at 08:13:32
The support docs link near the beginning of response 3 has the manuals for your model series. As I've already said, there is nothing in them I could find that would help.
Brand name system manuals almost always omit most if not all mboard pinout info, even if the mboard is a standard one.
They seem to assume if you bought a brand name system you're unlikely to ever need that info.

There are lots of relatively quiet case fans with standard female connectors you could custom mount to do the same thing as your blower fan. E.g. Startech's Mutant Mods fans are cheap, dual ball bearing, and not bad regarding noise.

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April 4, 2008 at 09:14:33
Thanks again Tubesandwires, you have been a great source of information reguarding the subject of my post! You are correct on there being alot of fans you can add to a PC to improve air flow inside the PC tower. In fact I have one installed already called a System Blower ! Its a slot fan however it actually takes up two slots because of the thickness of this powerful exhaust fan. When I first installed the ball bering fan it was so loud ,or perhaps it just seemed very loud because my PC was so very quiet. However after it was running for a couple of days it seemed to quiet down ,or I just adapted to the sound ? If it continued to seem so loud to me I would have removed it! Well I stated I have given up on tryng to hook up any on the Dell fans to the EasyWatch and the System Blower has a four pin plug ,so I cant hook that one up unless I knew enough to safley splice into the correct wires and was able to have it work properly and safley by doing that ? Just seeing the RPM of one fan isnt worth messing up my PSU or any other part of the PC ! Thanks again and have a nice weekend !
Take Care Nick

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April 4, 2008 at 10:02:03
"System Blower has a four pin plug ,so I cant hook that one up unless I knew enough to safley splice into the correct wires and was able to have it work properly and safley by doing that ?"

See the info in response 3 as well as the following.

The 4 pin holes in the female connector from the fan are probably wired and arranged the same as for a standard 3 wire fan for 3 of the 4 wires, 3 in a row being in the same order. The pins and pin holes are probably spaced the same - at .10" intervals - and will line up with each other. If the wires are colored, if there is a red wire, that probably goes on the center pin on the EasyWatch male connector - that would be either the second or third pin hole of the four. If there is a black wire that pin hole goes on the pin that has a black wire if that is what the Easy watch has. The other pin hole on the other side of the red wire goes on the other pin for rpm on the EasyWatch male connector.

If that isn't what wiring colors you see, the pinouts (what each pin connects to) for the 4 pin hole fan connector may be in the docs that came with it or on the manufacturer's site.
Another clue is the pins on the male connectors from the Easywatch are probably not dead center in the plastic that holds them, and the pin holes in the female connector from the fan are probably not dead center in the plastic that holds the female wire ends - they are probably closer to one side. The male connector will probably only go on the female connector facing one way. If that's the case, there are only two possible positions the male connector can plug into the female connector - one should work fine, the other will not.

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April 5, 2008 at 06:34:30
Thank's once again Tubesandwires again I have copied your reply into the same document as your other reply, Iam going to take a look at trying to make the System Blower give me some RPM readings on the EasyWatch ! I also want to apoligize for the many typos in my previous reply to you ! I was in a hurry and did not proof read the reply ,its embarassing to see so many mistakes in my typing. I will let you know if Iam able to get the slot fan to work with the EasyWatch ! Have a great weekend and Thanks Again
Take Care ,Nick

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