And is there any 4-pin 12V 1.5amp power adapter with speed control which can power the OEM apple fan right out of the box! This would solve all problems! 
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Can the imac 27 2019 fan be powered on using an external cable or usb port?
- Thread starter Neutral Singh
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The Noctua NA-FC1 controller would do that.
Or the AliExpress one with the knob.
They all are sold without psu so they can work with either 12v or 5v fans.
Or the AliExpress one with the knob.
They all are sold without psu so they can work with either 12v or 5v fans.
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In your L/top pic the iMac’s fan wires from Left to Right are:
+ve -ve Speed PWM
So the R/bottom pic is correct. 👍
+ve -ve Speed PWM
So the R/bottom pic is correct. 👍
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Can I use one of these cables to power-on the fan using noctua controller in a usb port of the computer, to eliminate power adaptor! These say that these supply 12V.
Or can you recommend a quality similar cable which will not ruin my computer or the usb port.
TIA
Or can you recommend a quality similar cable which will not ruin my computer or the usb port.
TIA
PWM 12V USB Fan Step-Up Connector Cable YACSEJAO 2Pack Full Speed 12V Step-Up USB to 3Pin/4Pin PC Fan Sleeved Power Adapter Cable
Specifications: Product Name: USB to 3-pin / 4-pin fan 12V Step-Up cable Function: change the 5V USB port to small 3 pin / 4 pin port for electricity use Connector: one is USB port, another one is small 3 pin / 4 pin case fan power adapter cable port Cable Length: 30cm/11.8inch Cable Type: 22AWG ...
www.amazon.com
CRJ 12V Step-Up USB to Dual PC Fans Power Adapter Cable - 24-inch (60cm), Black Sleeved - Full Fan Speed Adapter for 3-Pin/4-Pin Cooling Fans
The CRJ USB to Dual Fan Power Adapter Cable stands out as the first full-speed USB adapter designed to power computer fans, offering unparalleled flexibility in utilizing almost any fan, PWM controller, or compatible device. Equipped with a high-efficiency voltage step-up module, this cable deliv...
www.amazon.com
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They only supply 0.4amp.
The iMac fan takes up to 1.6 amps.
So you could very easily use too much power from the USB port which will cause MacOS to shut off the power and give an error message. It might blow the USB port.
The iMac fan takes up to 1.6 amps.
So you could very easily use too much power from the USB port which will cause MacOS to shut off the power and give an error message. It might blow the USB port.
Is it possible to power-on the Noctua directly from the internal power supply of the iMac?
If you run the iMac fan very slowly it should run on 0.4 amp.
If you turn the controller up any more MacOS will cut off power to the port.
The iMac power supply does provide 12v, plenty for the fan and the logic board.
BEWARE!!!!
If the power supply isn't COMPLETELY drained of any power it is possible to give you a LETHAL shock, the mains voltage is stored in the capacitors and the LCD Backlight voltage is much higher than 12v.
Leave it depowered for many HOURS before risking touching it.
If you do remove it GET ADVICE as to exactly what to connect to.
BEWARE!!!!
If you turn the controller up any more MacOS will cut off power to the port.
The iMac power supply does provide 12v, plenty for the fan and the logic board.
BEWARE!!!!
If the power supply isn't COMPLETELY drained of any power it is possible to give you a LETHAL shock, the mains voltage is stored in the capacitors and the LCD Backlight voltage is much higher than 12v.
Leave it depowered for many HOURS before risking touching it.
If you do remove it GET ADVICE as to exactly what to connect to.
BEWARE!!!!
Use your volt meter to measure the voltage of the old fan socket, if you can get 12V from that socket, it will be the easiest way to power you fan.
This:
https://www.amazon.com/CRJ-Voltage-Step-Up-Sleeved-Adapter/dp/B081K8LBH3
With
This:
https://www.amazon.com/Noctua-NA-FC1-4-pin-PWM-Controller/dp/B072M2HKSN
is running flawlessly via a usb port at full throttle... So, a 5V usb port is giving out 12V to Noctua controller, which in turn powering the OEM fan at 12V using a usb port of the same computer. Fan is running at a maximum speed for last few hours without an issue.
https://www.amazon.com/CRJ-Voltage-Step-Up-Sleeved-Adapter/dp/B081K8LBH3
With
This:
https://www.amazon.com/Noctua-NA-FC1-4-pin-PWM-Controller/dp/B072M2HKSN
is running flawlessly via a usb port at full throttle... So, a 5V usb port is giving out 12V to Noctua controller, which in turn powering the OEM fan at 12V using a usb port of the same computer. Fan is running at a maximum speed for last few hours without an issue.
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Now, the only problem remains is that usb continues to give power ouput when even the computer in sleep mode. No idea how to put usb port to sleep when the computer is sleeping...
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Your demand is opposite to many others'.
We need the USB port powered-on 24/7 for LED lighting, mobile devices charging, music listening on mini speakers,... even when the iMac is asleep.
I found an ingenious solution. Power Outlet with Digital Timer! The external power adapter shuts off automatically for a few hours when computer and myself are asleep and powers on automatically in the morning!
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Great info in this thread - I'm attempting a similar thing with the fan on a 2018 mac mini (after trying to change the fan, and getting nothing from smcFanControl). I'm struggling to find information on the wiring though - the best I could find was in a comment on a youtube video (!) but, like the original poster, I'm not sure how to translate that to the wire coming from the fan.
The comment said:
Pin 1 Speed Control Pin 2, 3 no connect Pin 4 +12v Pin 5 Ground Pin 6 Fan Rpm
Someone else commented:
For future Mac repairs those are Molex Pico-EZmate connectors, part number 781715006 for the six pin type, 781715004 for the four pin fan connectors on various MacBooks.
Anyone know if this is accurate, and which side pin 1 is on in the attached pic?
Thanks in advance.
The comment said:
Pin 1 Speed Control Pin 2, 3 no connect Pin 4 +12v Pin 5 Ground Pin 6 Fan Rpm
Someone else commented:
For future Mac repairs those are Molex Pico-EZmate connectors, part number 781715006 for the six pin type, 781715004 for the four pin fan connectors on various MacBooks.
Anyone know if this is accurate, and which side pin 1 is on in the attached pic?
Thanks in advance.
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Can the imac 27 2019 fan be powered on using an external cable or usb port?
@PaulD-UK, finally, the noctua controller is here... what will be correct order to connect the wires of the OEM fan? Notice the crossed black & red wires & the flipped fan in 2nd image. TIA
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Feedback after three months!
This solution works like a charm! Initially, the temperatures were hitting between 130 to 150 degrees F depending on the process, which were still on the higher side. At around 165 degrees F, it becomes almost unusable.
So, found another rather ingenious solution! I simply removed the memory door for an easier air flow behind the iMac and boom! the temperatures dropped dramatically to 100 to 120 degrees F even while running processor intensive tasks. This has also kept the fan noise to the bearable levels too with Noctua controller only running at 45% speed.
The iMac runs like a champion. Thinking about upgrading the processor to Core i9 9900K. 💕💕💕
Thanks @PaulD-UK & @Nguyen Duc Hieu for all the help!
This solution works like a charm! Initially, the temperatures were hitting between 130 to 150 degrees F depending on the process, which were still on the higher side. At around 165 degrees F, it becomes almost unusable.
So, found another rather ingenious solution! I simply removed the memory door for an easier air flow behind the iMac and boom! the temperatures dropped dramatically to 100 to 120 degrees F even while running processor intensive tasks. This has also kept the fan noise to the bearable levels too with Noctua controller only running at 45% speed.
The iMac runs like a champion. Thinking about upgrading the processor to Core i9 9900K. 💕💕💕
Thanks @PaulD-UK & @Nguyen Duc Hieu for all the help!
Good day,
Good day,
Question:
I presume you routed the power through a hole or other opening out of the iMac case to the power source? Any pictures or advice? I'm considering something similar, but am hesitant in doing so for presentation purposes... I'd like my iMac to still look aesthetically pleasing, but, have my additional cooling. Considering creating a double fan https://forums.macrumors.com/thread...cond-ssd-upgrade-air-vents-mod.2027485/page-3 By using a USB or AC powered solution for the 2nd fan as my 2020 iMac lacks something other than the power supply to directly tap to feed it.
You certainly could, however without beefing up the cooling to a double fan solution, assuming you've swapped out your spinner hard drive (if you have one) with an SSD to provide the space, i9 processor's in iMac's work, after roughly 60-90 seconds, the heat sink can (will) become "saturated" where it can't take any more heat and the fans can't keep up dispersing in which case your CPU will dial back (throttle) to the highest power level that corresponds with 100C on full fans, and in turn, your CPU will run at whatever frequency that corresponds with that power level.
This isn't a problem if you run "bursty" loads where the fans have time to chop back down the heat on the sink between loads, but if you're running an extended heavy load, you're not going to realize maximum potential of the i9 is all.
My 2 cents? I would. Consider buying a "delidded" copy on Fleabay. They should be floating around. You don't have to, the 9th gen i9's do use a higher quality TIM than 8th gen and older, but given a delid and not? The delid will give you much better performance on the front end where it can hit a more aggressive frequency for longer out the gate till it does throttle when the heat sink saturates.
What about the fan of 27 imac 2010Mid?My DIY 5K monitor which I built into a 2019 iMac case uses a 21 iMac fan, controlled by a PWM controller.
The 27 fan will run with 5 volts across the power wires at slow speed, ramping up as voltage is increased to 12v.
With the PWM controller the fan speed needs the temp sensor in the right place to control the fan.
This is my monitor build.
The PWM controller is pic 8 on the left.
DIY 5k Monitor - success :-)
My build is now more or less complete. Haha, I started out thinking minimally, but that's not how things have turned out - 6.66 Kg is the number of the beast, well its weight... 1. R1811, bought from Chinese seller on eBay UK. This is mounted so that access to the cable ports are retained...
Can it controlled by general PWM controller? Here's fan pic
Attachments
Quote:"What about the fan of 27 imac 2010Mid?
Can it controlled by general PWM controller?"
I can't see the power/control wires in you're pic, but if it's four wires then it will be PWM, and a controller will work.
Which wire is which needs to be tested...
Can it controlled by general PWM controller?"
I can't see the power/control wires in you're pic, but if it's four wires then it will be PWM, and a controller will work.
Which wire is which needs to be tested...