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#1
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Ongoing saga of the case fan
So, as I said before I had another fan failing and from the replies I
received about which fan to buy I purchased a Noctua fan with 3 wires which was what the case fan had. Lo and behold when I tried to install it the existing fan had a 3 wire fan with a 4 wire receptacle on the end which meant my new 3 wire fan would not fit. Even if I bent a wire over on the MB -which I would never do- the guide on the side of the receptacle would not match with the new fan. Different width. I have 4 wires on the MB so what would happen if I installed a 4 wire fan which would probably fit but I am concerned about an unanticipated bad happening. I don't like bad surprises. I appreciate any help. south walker mega 1999 |
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#2
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Ongoing saga of the case fan
On 01/24/2019 7:32 PM, swalker wrote:
So, as I said before I had another fan failing and from the replies I received about which fan to buy I purchased a Noctua fan with 3 wires which was what the case fan had. Lo and behold when I tried to install it the existing fan had a 3 wire fan with a 4 wire receptacle on the end which meant my new 3 wire fan would not fit. Even if I bent a wire over on the MB -which I would never do- the guide on the side of the receptacle would not match with the new fan. Different width. I have 4 wires on the MB so what would happen if I installed a 4 wire fan which would probably fit but I am concerned about an unanticipated bad happening. I don't like bad surprises. I appreciate any help. south walker mega 1999 Well if all the laws of electronics still hold, the 4 wire header on the MB must be a monitored and speed controlled fan header. I would exchange the 3 wire fan for a 4 wire and try it, I can't see any other reason or use for it. But if someone has better info on this please correct me if I'm wrong, I would not want someone to damage their gear on my say so alone. Rene |
#3
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Ongoing saga of the case fan
swalker wrote:
So, as I said before I had another fan failing and from the replies I received about which fan to buy I purchased a Noctua fan with 3 wires which was what the case fan had. Lo and behold when I tried to install it the existing fan had a 3 wire fan with a 4 wire receptacle on the end which meant my new 3 wire fan would not fit. Even if I bent a wire over on the MB -which I would never do- the guide on the side of the receptacle would not match with the new fan. Different width. I have 4 wires on the MB so what would happen if I installed a 4 wire fan which would probably fit but I am concerned about an unanticipated bad happening. I don't like bad surprises. The shroud around the 3-wire fan's connector should be narrow enough to miss the 4th pin in the mobo's header. Was there a shroud also around the mobo's 4-pin header or was it open (just the 4 pins sticking up with nothing around them)? Did you give the mobo's brand and model in your original query? If not, respondents are going to assume the default of just a 3-pin fan (or even a 2-pin fan if the BIOS doesn't try to control its speed). With vague details, expect generic answers. In your thread titled "Case fan replacement OT", you never identified the brand and model of your motherboard. Specifics matter. In that prior fan, *you* said the original fan AND the mobo had only 3 pins. So what changed to physically alter the mobo header from 3 to 4 pins? Did you swap out the mobo, too? 3-wire fans use PWM (pulse width modulation) to change the speed of the fan. The signals a +5V, ground, and RPM sense (FAN_TACH). To change that fan's speed, its voltage is modified to change its duty cycle (how long the 5V goes high and how long it is low within one cycle). A shorter duty cycle (how long 5V is applied) with a cycle means a lower average voltage over that cycle. A longer duty cycle means the 5V is high during more of the cycle meaning an average higher voltage during that cycle. That assumes the 5V power line can be modified regarding its duty cycle and that requires a controller on the mobo. 4-wire fans have a line for RPM sense (FAN_TACH) to monitor the speed of the fan and another line (FAN_CONTROL) to specify RPM to the fan. Its voltage remains constant at 5V and it is the fan that is told what RPM to run at. 3-wire fans need no logic within but do have to operate with a fluctuating 5V line. 4-wire fans have internal logic that communicates with the mobo over the FAN_CONTROL line to have the fan itself decide what RPM to spin at. If you connect a 3-wire fan to a 4-pin header on the mobo (might require prying off the polarization shroud around the mobo header), and since that header is designed for regulating fan speed by telling it via FAN_CONTROL what speed to run (but you won't be using that pin) and won't use PWM for that header, the 3-wire fan will run at full speed. The fan will report its RPM using the FAN_TACH line but has no means of regulating the fan's speed since it won't use PWM on that header and you didn't use the 4th pin (FAN_CONTROL). You started a new and disconnected thread to continue your prior discussion. After looking up "EVGA Precision XOC", that is not a separate fan controller, like one that slides into an external drive bay in the case. Instead it is just a software-based fan controller program that works with a particular mobo. That means you really should match the number of pins on the fan to the number of pins on the mobo's header for that fan. Don't know from whom you ordered the Noctua fan. I know with Newegg that I've been able to return parts that were wrong. If it was there error then there is no restocking fee. If it was my error, there might be a restocking fee. Plus you'll have to pay the return shipping, so maybe just keep the 3-pin fan for some other future project, decide to let it run at full speed by sliding it onto the correct 3 pins of the 4-pin header on the mobo, or return it for a [partial] refund and get a fan that matches the mobo header. |
#4
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Ongoing saga of the case fan
swalker wrote:
So, as I said before I had another fan failing and from the replies I received about which fan to buy I purchased a Noctua fan with 3 wires which was what the case fan had. Lo and behold when I tried to install it the existing fan had a 3 wire fan with a 4 wire receptacle on the end which meant my new 3 wire fan would not fit. Even if I bent a wire over on the MB -which I would never do- the guide on the side of the receptacle would not match with the new fan. Different width. I have 4 wires on the MB so what would happen if I installed a 4 wire fan which would probably fit but I am concerned about an unanticipated bad happening. I don't like bad surprises. I appreciate any help. south walker mega 1999 3 wire fans fit on 4 pin motherboard connectors. You make sure that pin 1 mates with pin 1. The latch should be on the correct side. The 3 wire fan will run at full speed, and the RPM (rotation speed) will work. See how the latch position in this picture, guides you to the pin 1 end ? The body of the 3 wire connector should not be so wide that it can't fit. https://allpinouts.org/img/connector...wm_3to4pin.png 4 wire fans fit on 3 pin motherboard connectors. The fourth "hole" overhangs the end of the connector. The latch should be on the correct side. The four wire fan will run at full speed (since the PWM signal is floating and not driven). The RPM signal will work. https://allpinouts.org/img/connector...wm_4to3pin.png 3 wire on 3 pin. RPM works. If mobo has Vfan adjust, speed is adjustable. 4 wire on 4 pin. RPM works. PWM works so speed is adjustable. This one is more likely to have speed control. Reference: https://allpinouts.org/pinouts/conne...cpu-4-pin-fan/ Paul |
#5
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Ongoing saga of the case fan
"swalker" wrote in message ... So, as I said before I had another fan failing and from the replies I received about which fan to buy I purchased a Noctua fan with 3 wires which was what the case fan had. Lo and behold when I tried to install it the existing fan had a 3 wire fan with a 4 wire receptacle on the end which meant my new 3 wire fan would not fit. Even if I bent a wire over on the MB -which I would never do- the guide on the side of the receptacle would not match with the new fan. Different width. I have 4 wires on the MB so what would happen if I installed a 4 wire fan which would probably fit but I am concerned about an unanticipated bad happening. I don't like bad surprises. I appreciate any help. south walker mega 1999 A 3-pin fan will work on a 4-pin MB connector, and a 4-pin fan will work on a 3-pin MB connector: https://allpinouts.org/pinouts/connectors/motherboards/motherboard-cpu-4-pin-fan/ Notice the tab on the MB is offset to allow the 3-pin fan to only connect to pins 1, 2, & 3. The guides on a 4-pin fan plug are offset also to allow it to go on only 1 way. HTH. -- SC Tom |
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