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4-pin PMW fan with only 12V and ground connected?

PH!L
By PH!L
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I have 3 PMW 4-pin fans that I want to connect directly to my PSU. I have a molex to 3x3-pin adapter whith only the 12V and ground pin. Would there be any issues if I just cut them up a bit to make the 4-pin fans fit in there? I'm guessing that they would just run at full speed but work fine but I don't want to risk 100$ worth of fans without asking before I do it.

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1 minute ago, PH!L said:

I have 3 PMW 4-pin fans that I want to connect directly to my PSU. I have a molex to 3x3-pin adapter whith only the 12V and ground pin. Would there be any issues if I just cut them up a bit to make the 4-pin fans fit in there? I'm guessing that they would just run at full speed but work fine but I don't want to risk 100$ worth of fans before I do it.

It will work fine, but why not plug them into your mobo so they can be controlled based on heat, and not run loud and annoyingly all the time at 100%.

Rig: i7 13700k - - Asus Z790-P Wifi - - RTX 4080 - - 4x16GB 6000MHz - - Samsung 990 Pro 2TB NVMe Boot + Main Programs - - Assorted SATA SSD's for Photo Work - - Corsair RM850x - - Sound BlasterX EA-5 - - Corsair XC8 JTC Edition - - Corsair GPU Full Cover GPU Block - - XT45 X-Flow 420 + UT60 280 rads - - EK XRES RGB PWM - - Fractal Define S2 - - Acer Predator X34 -- Logitech G502 - - Logitech G710+ - - Logitech Z5500 - - LTT Deskpad

 

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1 minute ago, PH!L said:

I have 3 PMW 4-pin fans that I want to connect directly to my PSU. I have a molex to 3x3-pin adapter whith only the 12V and ground pin. Would there be any issues if I just cut them up a bit to make the 4-pin fans fit in there? I'm guessing that they would just run at full speed but work fine but I don't want to risk 100$ worth of fans before I do it.

ya just work like a 3pin fan wood. but imo making your own pwm hub would be better or buying one. but up to you.

could also do the 12v 7v 5v mod as well.

I have dyslexia plz be kind to me. dont like my post dont read it or respond thx

also i edit post alot because you no why...

Thrasher_565 hub links build logs

Corsair Lian Li Bykski Barrow thermaltake nzxt aquacomputer 5v argb pin out guide + argb info

5v device to 12v mb header

Odds and Sods Argb Rgb Links

 

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5 minutes ago, PH!L said:

I have 3 PMW 4-pin fans that I want to connect directly to my PSU. I have a molex to 3x3-pin adapter whith only the 12V and ground pin. Would there be any issues if I just cut them up a bit to make the 4-pin fans fit in there? I'm guessing that they would just run at full speed but work fine but I don't want to risk 100$ worth of fans before I do it.

1. Why spend 100 USD on fans, while you can't even plug them into something proper?

2. Why not get some small extension cables (just get the cheapest simplest which should be a couple USD), which you plugs into the fan leads and cut up that cheap cable? That way you have your fans intact for when you do have a proper solution

3. yes they will run at full speed, the fans.

"We're all in this together, might as well be friends" Tom, Toonami.

 

mini eLiXiVy: my open source 65% mechanical PCB, a build log, PCB anatomy and discussing open source licenses: https://linustechtips.com/topic/1366493-elixivy-a-65-mechanical-keyboard-build-log-pcb-anatomy-and-how-i-open-sourced-this-project/

 

mini_cardboard: a 4% keyboard build log and how keyboards work: https://linustechtips.com/topic/1328547-mini_cardboard-a-4-keyboard-build-log-and-how-keyboards-work/

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1 minute ago, LIGISTX said:

 why not plug them into your mobo 

I have only 5 headers and 3 other fans and a pump i need to connect. Also I read somewhere that you realy shouldn't overload your fan connecters. Aparently my mobo can do 1A across all headers but my fans draw like 1.8 total I think.  But mainly the lack of headers and the fact that I allready have the cable to solve the problem.

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2 minutes ago, minibois said:

1. Why spend 100 USD on fans, while you can't even plug them into something proper?

I already had the fans and they used to be connected differently but I changed the build around and dont have enough headers. I might get a fan controller in the future but for now im wondering if I can connect them all this way for now.

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2 minutes ago, PH!L said:

I already had the fans and they used to be connected differently but I changed the build around and dont have enough headers. I might get a fan controller in the future but for now im wondering if I can connect them all this way for now.

Definitely do not cut the PWM cables off of the fans.

Keep in mind using a fan splitter it's usually possible to connect two or three fan to one header.

For example the LL120 fans from Corsair (only fans I could think off that are 100 USD for three) use 0.3a. With your motherboard ports being able to do 1a, that means you can connect three of these on one fan header.

 

"We're all in this together, might as well be friends" Tom, Toonami.

 

mini eLiXiVy: my open source 65% mechanical PCB, a build log, PCB anatomy and discussing open source licenses: https://linustechtips.com/topic/1366493-elixivy-a-65-mechanical-keyboard-build-log-pcb-anatomy-and-how-i-open-sourced-this-project/

 

mini_cardboard: a 4% keyboard build log and how keyboards work: https://linustechtips.com/topic/1328547-mini_cardboard-a-4-keyboard-build-log-and-how-keyboards-work/

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1 minute ago, minibois said:

Definitely do not cut the PWM cables off of the fans.

Keep in mind using a fan splitter it's usually possible to connect two or three fan to one header.

For example the LL120 fans from Corsair (only fans I could think off that are 100 USD for three) use 0.3a. With your motherboard ports being able to do 1a, that means you can connect three of these on one fan header.

 

Sorry if i was unclear. I meant cut up the plastic around the fan headers on the molex to 3 pin adapter to make the intact pmw cables fit. Did I missunderstand what I read then ? I thought the 1A ratining was across all headers.

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3 minutes ago, PH!L said:

Sorry if i was unclear. I meant cut up the plastic around the fan headers on the molex to 3 pin adapter to make the intact pmw cables fit. Did I missunderstand what I read then ? I thought the 1A ratining was across all headers.

I am unsure what you read or what motherboard you have, but the rating you see in the manual is for each header:

image.thumb.png.d2701adb86e3ebf9ec3a2b38a74116f6.png

This is just a random ASUS X570 board, which I looked up because I know they show the information quite clear.

 

As you can see, most headers can draw 1A/12W and can be controlled via Q-Fan (their implementation of fan control).

That means I could put - via a splitter - three LL120 fans on one header. That way you control all three at once, so if one runs at 100%; they all do.

"We're all in this together, might as well be friends" Tom, Toonami.

 

mini eLiXiVy: my open source 65% mechanical PCB, a build log, PCB anatomy and discussing open source licenses: https://linustechtips.com/topic/1366493-elixivy-a-65-mechanical-keyboard-build-log-pcb-anatomy-and-how-i-open-sourced-this-project/

 

mini_cardboard: a 4% keyboard build log and how keyboards work: https://linustechtips.com/topic/1328547-mini_cardboard-a-4-keyboard-build-log-and-how-keyboards-work/

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9 minutes ago, minibois said:

I am unsure what you read or what motherboard you have, but the rating you see in the manual is for each header:

My manual just said 1A rating for fan headers and I read somewhere on a different forum that that usualy means across all of them. Alltough I did find it weird that my pretty high end mobo (MSI Z370 Gaming Pro Carbon) wouldnt even be able to run 4 power intensive fans, so guess it is for each one. So I'll get a fan splitter in the future and jerry rig it for now. Thanks for the help!

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5 minutes ago, PH!L said:

My manual just said 1A rating for fan headers and I read somewhere on a different forum that that usualy means across all of them. Alltough I did find it weird that my pretty high end mobo (MSI Z370 Gaming Pro Carbon) wouldnt even be able to run 4 power intensive fans, so guess it is for each one. So I'll get a fan splitter in the future and jerry rig it for now. Thanks for the help!

Couldn't find a specific table like I showed above for your motherboard, so I would have to guess it's 1A per port.

"We're all in this together, might as well be friends" Tom, Toonami.

 

mini eLiXiVy: my open source 65% mechanical PCB, a build log, PCB anatomy and discussing open source licenses: https://linustechtips.com/topic/1366493-elixivy-a-65-mechanical-keyboard-build-log-pcb-anatomy-and-how-i-open-sourced-this-project/

 

mini_cardboard: a 4% keyboard build log and how keyboards work: https://linustechtips.com/topic/1328547-mini_cardboard-a-4-keyboard-build-log-and-how-keyboards-work/

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