My iMac 27 2019 fan is not working. Looks like a Logic Board issue. So, the CPU gets hot and computer starts behaving really slow after sometime. Rather than spending a fortune on the repair, I was wondering, can the imac four pin fan be powered on using a special external cable via usb port of the imac itself or any normal power adapter? Has anybody explored this path? Thanks
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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 fan connector in your picture does not appear to be completely seated... (might be OK, just a mention that it doesn't look tight in your picture)
If you are already at the fan, then just three screws, and a little fiddling with some tape to remove the fan.
Takes less than 2 minutes to replace the fan. That, of course, is if you still have the iMac front open, and the display out (the hardest part of the job)
Replacement fans (if you can find one) are mostly less than $20
If you are already at the fan, then just three screws, and a little fiddling with some tape to remove the fan.
Takes less than 2 minutes to replace the fan. That, of course, is if you still have the iMac front open, and the display out (the hardest part of the job)
Replacement fans (if you can find one) are mostly less than $20
The iMac 27 fan is a regular PWM 4 pin fan but Apple swaps the power wires, so the 4 wires are + - Speed PWM (L to R in your pic as they exit the fan hub) with 12 volts needed. You can control the fan with a cheap 4 pin PWM controller with a temp probe.
I don’t know if the logic board will freak out if you disconnect the fan.
I don’t know if the logic board will freak out if you disconnect the fan.
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The fan connector is perfectly flush. I have tried replacing the fan also, nothing happens. So, looks like an issue with Logic Board.
So, the fan would be totally independent of the logic board. Wire will run out from the exaust vent and powered on independently, so the logic board should not freak out.
How can this achieved? any video or step step guide be awesome. TIA
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.
forums.macrumors.com
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...
forums.macrumors.com
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Thats some serious modding! For layman like me, is it possible just power the fan directly without much complexity or modding. Thanks
How about something like this?
www.aliexpress.us
How about something like this?
DC 12V PWM Speed Controller Fan Speed governor 4 Wire Computer Temperature control Switch for PC CPU Cooler Fan Manual Stop - AliExpress 13
Smarter Shopping, Better Living! Aliexpress.com
The first one should work - the knob makes control easier.
It needs 12v at 1.5 amp psu, although less than 1 amp is needed for medium/low speeds. where it would normally operate.
Run the wires to the fan, and have the controller outside the case, with its psu.
Remember the + - swap on the fan.
It needs 12v at 1.5 amp psu, although less than 1 amp is needed for medium/low speeds. where it would normally operate.
Run the wires to the fan, and have the controller outside the case, with its psu.
Remember the + - swap on the fan.
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This?
Universal 12V 1.5A AC DC Power Supply 2.1mm Adapter Switch 18W Charger CCTV LED | eBay
100 PCS Female DC Power Jack Adapter Plug 5.5mm 2.1mm for CCTV LED Strip Light. Fast Wire 10 pcs Male DC Power Adapter Plug 5.5 x 2.1 mm LED Strip Light CCTV. 100 PCS Male DC Power Jack Adapter Plug 5.5mm x 2.1mm for CCTV LED Strip Light.
www.ebay.com
Ordered! will keep you updated of the progress! Thank youThats some serious modding! For layman like me, is it possible just power the fan directly without much complexity or modding. Thanks
How about something like this?
DC 12V PWM Speed Controller Fan Speed governor 4 Wire Computer Temperature control Switch for PC CPU Cooler Fan Manual Stop - AliExpress 13
Smarter Shopping, Better Living! Aliexpress.com
I think the module below is better.
Thank you! How to power it on? I need a mechanism which can power the internal iMac fan from an external source, which allows me to control the fan speed as well. Thank you
I am leaning towards ordering this config as well. would this power on the internal imac 2019 fan out of the box?
Noctua NA-FC1, 4-Pin PWM Fan Controller (Black)
Noctua NA-FC1 contrôleur de vitesse du ventilateur 3 canaux Noir
www.amazon.com
Coolerguys Fan Power Supply 100-240v AC to 12v DC 1A Output 3pin or 4pin PWM Connector AC DC Adapter
Coolerguys is proud to launch our most cost effective branded 1A power supply. We simplified to have a 2510 (3+1) fan connector to directly power either a 3pin and 4pin PWM fans with no adapter. The native cable is 5ft (1.5m), but can easily use any standard 3pin or 4pin extension or splitter. 10...
www.amazon.com
It uses 12V, you can screw in 2 wires from an external 12V adapter, or take it directly from the iMac PSU, if you want 100% internal. It's thermal controlled, too.
Check the pdf file for a clear user guide including how to set the DIP switches.
Found this easy solution right out of the box!
Wathai 120mm x 32mm USB Centrifugal Blower Fan 5V DC Brushless Motor with Speed Control for Receiver DVR Xbox Modem AV Cabinet Efficient Cooling
Wathai 120mm x 32mm USB Centrifugal Blower Fan 5V DC Brushless Motor with Speed Control for Receiver DVR Xbox Modem AV Cabinet Efficient Cooling
www.amazon.com
That's a 120mm fan (32mm deep) which is bigger than the iMac' original fan.
The cable socket connecting the screen may make it too tight a fit.
And it certainly will be noisier that the original fan a lower speeds.
The cable socket connecting the screen may make it too tight a fit.
And it certainly will be noisier that the original fan a lower speeds.
Yeah! also, ordered the slimmer version of the same brand.
Let us see which one fits better... Amazon allows 30days to return, so gives me time to play with things!
The sound DB levels also seem to the comparable with the OEM fan... let us see! 🤞🤞
Ok, did some research - OEM Apple fan produces around 24DB where as these third-party fans can produce around 30DB, hope its bearable or else will have to look for quieter fans, thanks for pointing attention to this aspect!
The Wathai fan/controller is a simple 2 wire voltage controller, going down to 4v at its minimum.
The Apple standard fan will work down to 4.5v across its + and - wires (with no PWM control wire), but its still quite fast and noisy even at this minimum voltage.
When a 4 wire PWM controller is connected (like the Noctua or the AliExpress boards) then the Apple fan will drop to a far lower speed, under 6-10 revs/second. At this speed it is virtually silent.
This is how it is operating in the iMac when the CPU/GPU is idle or at low loads. Virtually inaudible.
Only when you load the iMac's CPU/GPU does it speed the fan up - but never at anything near maximum.
The PC fan will never work like this at low power levels. It will always be audible.
The Noctua controller replicates the Apple controller with a 5 r/s minimum speed. With a knob to ramp it up as needed.
The Apple standard fan will work down to 4.5v across its + and - wires (with no PWM control wire), but its still quite fast and noisy even at this minimum voltage.
When a 4 wire PWM controller is connected (like the Noctua or the AliExpress boards) then the Apple fan will drop to a far lower speed, under 6-10 revs/second. At this speed it is virtually silent.
This is how it is operating in the iMac when the CPU/GPU is idle or at low loads. Virtually inaudible.
Only when you load the iMac's CPU/GPU does it speed the fan up - but never at anything near maximum.
The PC fan will never work like this at low power levels. It will always be audible.
The Noctua controller replicates the Apple controller with a 5 r/s minimum speed. With a knob to ramp it up as needed.
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Thank you! The ones I have ordered have speed control knobs and the one i ordered from aliexpress would take atleast a month to deliver... gives me time to experiment... 💁♂️
Will these work with Noctua?
WDERAIR 120mm x 32mm Dual Ball 4Pin DC Computer Centrifugal Blower Fan 12V PWM Big Airflow for DIY Air Exhaust Vent Cooling
I used it to cool a microwave in a cupboard. Works great as a replacement for inflatables. Ventilate the space above an aftermarket oven in my RV. Using it inside an incubator cabinet. the adjustable speed is great. Bought this for my 3D printer cabinet. Exactly what I needed, robust and powerful...
www.amazon.com
GDSTIME 120mm PWM 4 Pin 12V Dual Ball Bearing DC Brushless Blower Cooling Fan (4.72x4.72x1.26 inch), for Car Seat Amplifier Inflatables Inverter Ventilation
GDSTIME 120mm PWM 4 Pin 12V Dual Ball Bearing DC Brushless Blower Cooling Fan (4.72x4.72x1.26 inch), for Car Seat Amplifier Inflatables Inverter Ventilation
www.amazon.com