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Cpu fan not work, replacement not work

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October 23, 2012 3:42:44 PM

ASUS M4N78 Pro
amd Phenom II X4 955 Black Edition 3.2GHz AM3
COOLER MASTER Hyper 212 Plus
Thermaltake Purepower W0129RU 600 W

went to boot cp up, it said cpu fan not working, sure enough its not working. the cpu is a year and 2 months old.

so i buy the cooler master hyper 212 install it, it boots up no problem. so i shut down because i have to work.
last night, second time booting up with the hyper 212 installed, it says cpu fan not working.

so im guessing my motherboard cpu fan connector is bad, but is there an adapter to run the cpu fan without using the cpu fan connector on the motherboard?

is there a way to test the hyper 212 fan to make sure it is in working order and not in need of a return?
a b B Homebuilt system
a c 124 à CPUs
October 23, 2012 5:04:10 PM

Have you tried the other fan connectors on your mobo?
October 23, 2012 5:12:37 PM

the connector doesnt fit any other connections. its a 4 pin cpu fan connector
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a b B Homebuilt system
a c 124 à CPUs
October 23, 2012 5:47:54 PM

A 4 pin may still fit on a 3 pin. The 4th pin is just so you can control the speed which isn't necessary if you just want to test if it works.

There are 4 pin to 3 pin adapters. Or 4 pin to molex.

Another option is to just take the wires out (push pin on one side) and stick it in a molex off the psu. I've done this to test a 2 pin fan's speed. http://www.hardwaresecrets.com/article/How-to-Create-a-...
a b à CPUs
October 23, 2012 6:05:19 PM

it's probably the mobo connector. yes they make adaptors. you can put it on any 3pin port on the mobo tho.

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a b B Homebuilt system
a b à CPUs
October 23, 2012 6:12:23 PM
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You MIGHT just have a CPU_FAN connector with dirty pins, since the problem appears to be intermittent. Disconnect power, open the case, and unplug the CPU fan from mobo. Use some mildly abrasive material - a fingernail emery board, a bit of steel wool, a piece of fine emery paper - to clean the pins of the mobo's connector, then carefully remove any dust you created with this. Now plug the CPU cooler back into the mobo port. WAIT! Unplug and re-connect a few times to "scrub" the metal part together and ensure a clean connection. Now close up the case, reconnect power and try it.

If that does not do the trick, you can test your new fan by plugging it into a 3-pin SYS_FAN connector on the mobo. Yes, the 4-pin connector from the fan will plug in there - it just won't have a Pin #4 to connect to. A 4-pin fan connected this way should operate just like a 3-pin fan, varying its speed according to the output of the SYS_FAN connector. (NOTE: see my comment below about ignoring the CPU fan speed when you do this test connection.) HOWEVER, this is just to test the fan - it is NOT a long-term way to operate. The mobo's CPU_FAN control system is based on a temp sensor built into the CPU chip itself. The SYS_FAN port's fan speed control is based, instead, on a temp sensor in the mobo somewhere, and that sensor is NOT a good way to estimate the internal CPU temp. So, if your CPU_FAN port can't be made to work reliably, you're better off using an adapter to connect the CPU cooling fan to a 4-pin Molex output from the PSU, thus allowing it to operate at full speed at all times. That's not as quiet, maybe, but it will ensure the CPU gets more-than-adequate cooling. IF you have to do this, you will need to go into BIOS Setup and disable automatic CPU fan cooling control and tell it to ignore that fan's speed. When you power the CPU cooling fan from any port other than the CPU_FAN port, there is no way for the fan speed signal to be sent back to the mobo, and the mobo will go into a panic, tell you the CPU fan failed, and shut down to protect it! That's why you have to tell the BIOS Setup screen for this fan to stop worrying about it. NOTE that you probably would have to do this same "ignore the non-existent signal" thing when you test your fan by plugging into a mobo SYS_FAN port.
October 23, 2012 6:41:31 PM

Best answer selected by cruzer.
October 23, 2012 6:48:04 PM

doh i feel like an idiot. i looked for another 3 pin to connect the cpu fan to, but i didnt see it. just checked again and found it. it does work.

running it this way, it says its running at 1880 rpms, the max temp under load from a game, a messenger, utorrent was 42 celcius. is this acceptable?

can you guys link me to the adapter i can use to connect the cpu fan to molex?
a b B Homebuilt system
a b à CPUs
October 26, 2012 5:45:50 PM

Do you mean there was a second CPU_FAN port on the mobo with 3 pins instead of 4? That is quite handy!

Here are 2 adapters you could use.

http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

and even a 3-pack bargain:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Each has a male 4-pin Molex connector to plug into the output from your PSU, a 3-pin male connector for the fan, and a 4-pin Molex female connector to replicate the one "used up" from the PSU.
October 26, 2012 6:01:56 PM

it was not a cpu fan port, it was a chassis fan port

thanks for the links!!!
a b B Homebuilt system
a b à CPUs
October 27, 2012 9:27:20 PM

Since you won't be connecting your CPU cooling fan to the CPU_FAN port, a direct connection to a 12 VDC supply from a Molex is a good way. You may have to tell the BIOS (as I said before) to ignore the CPU fan speed checks. However, it will still monitor the actual CPU temperature as measured by the chip's internal sensor, and slow down or shut down your system it CPU temp gets too high.

Here's another possible connection source for your CPU fan on the mobo. SOME (not all) mobo's have a 3-pin fan connection up near the top labelled PSU_FAN or something similar. It is designed to allow you to plug in a special connector (exactly like a standard 3-pin fan connector) coming out of your PSU (IF you have this set of wires - some PSU's don't) so you can monitor the speed of the fan inside your PSU, although you cannot do any control of that fan. Normally, if you have no such leads coming from your PSU, you connect nothing to this optional mobo connector. But some of these PSU_FAN ports actually have the Ground and (constant) +12 VDC lines live, so if you plug a 3- or a 4-pin fan into it, that fan will run at full speed at all times - just the same as if it were plugged into a Molex output connector. Small plus point - if you do this, the mobo can read and display the speed of the fan plugged in here (it would be your CPU cooling fan), but it will think it is the PSU internal fan.
!