Can anyone help me identify this 3 pin CPU fan socket?

tjrobinson

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Apr 23, 2006
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Hi,

I'm hoping somebody might be able to help me out. I've got an old Dell Optiplex GX150 and I'm trying to fit a new CPU fan. Unfortunately the motherboard socket for the fan itself is non-standard and I can't find a suitable adapter.

dell-optiplex-cpu-fan-cable.jpg


I've got a new 60mm fan with a standard 3 pin plug, but it doesn't fit the socket on the motherboard. Does anyone know of an adapter I could use? Does anyone know what this type of socket is called? I guess I could run it straight from the main power supply using a 4 pin to 3 pin adapter but I'd rather use the proper socket if possible.

Thanks :)
 

Grimmy

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Feb 20, 2006
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Your going to have to consult you manual, and find the schematic for the 4 pin out, on the dell MB.

The 3 pin pic that you have.. I believe:

1 (white) tach (for RPM reading)
2 (red) 12V+ or 5V+
3 (black) ground

The red and black are usually common colors for Voltage and ground.

I'm not sure if they have an adaptor for it, and since its 3 pin that you brought, your going to loose some kind a feature it has, I'm guessing fan control.

They do sell 4 pin CPU HSF if you look for them. Other then that your going to have to mod (cut wires / loose fan feature) or find an adaptor to work in place of it, still loosing fan control, if you are going to use that 3 pin on a 4 pin.

Or you might be able just to go out and find another fan that is 4 pin.
 

tjrobinson

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Apr 23, 2006
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Hi,

Thanks for the reply. I think I've confused you though, both the motherboard socket, the existing fan and the new fan are all 3 pin (white, red, black).

When I said 4 pin, I meant I could connect the new CPU fan straight to the main power supply from a standard 4 pin (molex?) connector. Obviously doing this would mean losing speed control, hence prefering to find an adapter which lets me plug my 3 pin fan plug into a 3 pin motherboard socket.

Hope that makes sense?
 

Grimmy

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Yes, you did confuse me.

Some MB have a 4 pin on the MB. So I remembered what I found on that as far what each pin did.

Though, since your saying the 4 molex power from the PSU, your going to loose RPM readings by powering it that way. When you power up your PC, it may stop at the POST screen saying you have some kind of monitor problem from not having any RPMs from the CPU fan as well. You may have to set the bios to ignore the CPU RPM, if you do it that way.

If you are sure it will not plug in correctly, you can use the other plug, by cutting the wire and re-wire the new fan to the old plug, or spending a few bucks on something that has a 2 pin from a 4pin molex plug.

Edit:

I guess this is what you may be looking for, if you want power from the PSU directly for the fan.

3 pin - PSU molex adaptor

812269f3-fec7-4a35-91c7-66ac89303d41.gif
 

joefriday

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Feb 24, 2006
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Yank out the black plastic bit surrounding the CPU fan socket with a plier. Very easy.
Now you can plug your standard 3pin fan plug in. Note that pin arrangement are the same.

Or, conversely, buy new fan, cut off connector and solder old connector onto it. That's what I did with my GX50.
 

tjrobinson

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Yank out the black plastic bit surrounding the CPU fan socket with a plier. Very easy.
Now you can plug your standard 3pin fan plug in. Note that pin arrangement are the same.

Yea, I was wondering about that. The pins certainly seem to line up, though I was worried about taking off the socket surround on the motherboard, just in case it breaks something.

Rewiring the new fan is a safer option, but I assume I'd need to do some soldering and my nearest soldering iron is 200 miles away.

I'll give the existing socket surround a little pull and see if it comes off easily.

And yes, there is a spider web on the cable!
 

Sleepy2

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If the wire on the existing plug and the new plug are similar gauge, you may be able to remove wires and steel end connections from the standard new plastic plug and move to the old dell plug and reuse it. No cutting or soldering required. Your photo shows small metal tabs locking the wires into the unusual three pin dell plug, press these down and pull the wire out of the plug. See if the new fans wires are removeable from the standard plug, although most I've seen have small plastic flaps which can be moved to unlock the wires - remove a wire and try fitting it into the dell plug.

(USB header pins - 9 or 10 - on old mother boards quite often have strange wiring layouts and require this to rearrange wiring on modern internal USB fittings such as card readers and case fittings for front USB ports)
 

tjrobinson

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Apr 23, 2006
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I just wrote a longer post but lost it, so I'll keep this brief.

- The black socket surround on the motherboard wouldn't come off.
- The wires on the new fan cable wouldn't fit into the old plug.
- I cheated and skipped the CPU fan socket, using one of these instead.

It's not ideal, but it works.
 

Grimmy

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The fan socket and plug on his current one is a 3pin.
There are no 4pin anywhere in that picture.

THANKS FOR POINTING THAT OUT AFTER HE TOLD ME.

After I did say:

Yes, you did confuse me.

JUST LOVE IT WHEN I SEE IT NEEDS TO BE TOLD TO ME BY SOMEONE ELSE THE 3RD TIME AROUND. :p

Edit:

LOL so the pastic 3 pin socket wouldn't come off. I would have just used the old plug from the other fan. I assume that it (fan being replaced) is no longer working, so why not just use its plug on the new fan. Using dikes, stripper, electrical tape should have done the job.

But I guess you found the same thing I found to use power off the PSU.
 
G

Guest

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I just had same problem...there is a small tab connecting socket surround to MB...I snipped it and surround came off easily...still having prob w/fan sensor tho.