A1466 cooling fan stops working but works if external 5v is on.

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MacBook Air 13" mi-2012

Intel Core i5 bicœur avec 3 Mo de mémoire cache L3 de 1,8 GHz

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jade @jadelyly

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Publié: 26 sept. 2019

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A1466 cooling fan stops working but works if external 5v is on.

Hello, after replacing keyboard and battery of A1466, there was no issue at first.

But eventually my fan does not rotate....(maybe a week later).

I have an arduino which can test cooling fan with valtage of 5v and ground.

After testing, there is no issue. The fan rotates, but not on the macbook.

There are also 5v, ground, and 3v out in 4 pins of fan connector of Logic board.

I did SMC reset..no work..macbook starts up but no fan running I wonder if cpu will be burned out when cooling fan does not work…

What happened to my fan? Do I need to buy new one?

this is with fan

this is without fan

@danj

it is 80 degrees but fan does not work…..

@danj

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@jadelyly - Lets push the system a bit harder your temps are still low.

28 sept. 2019 par Dan

OK, not good!

Are you sure your fan is OK? Have you tried a second one?

You'll need to take the logic board out to inspect the back side for liquid damage around the SMC logic and/or damaged/missing components.

Do you have the skills and access to the needed parts to replace damaged or missing components? If not it might be easer just replacing the logic board.

28 sept. 2019 par Dan

@danj okay replacing logic board is too expensive..I will buy a new fan and test smc logic component with tester..if result is no good..I will say goodbye to my macbook..thanks anyway

28 sept. 2019 par jade

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arbaman @arbaman

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Publié: 26 sept. 2019

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On your Air fan is controlled by the SMC through some resistors and a MOSFET on the flip side of the board. It may be something got shorted or damaged by mistake along with the replacements.

You might want to check the SMC related cables such as the one going to trackpad and I/O board are well in place, but beside that, one would need to probe the fan circuitry to get some clear answers about the why.

Buying a new fan will be useless since yours works when plugged to an external source. You probably need someone who can provide component level repairs to get it fixed. Running without a fan will probably start causing thermal shutdowns and cook the CPU.

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I would install this app to help see the thermal load and what the fan is doing TG Pro the free version should offer enough info.

27 sept. 2019 par Dan

thanks for your reply, but thre are 5v and 3.3v out in the fan connector of logic board. Does this mean SMC is not the issue?

27 sept. 2019 par jade

@jadelyly SMC doesn't create voltages, it just uses them to modulate signals. I can't say what's wrong without testing and in the end it doesn't really make a difference..does it ?

27 sept. 2019 par arbaman

@jadelyly - Post a snapshot of TG Pro here for us to see.

These fans have a feedback system (tachometer). Measuring voltages doesn't tell you much unless you understand the logic thats controlling the fan.

27 sept. 2019 par Dan

@danj fan diagnostics reauire a registration. is there any way to use this function with trial licesnse?

27 sept. 2019 par jade

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@jadelyly - Lets push the system a bit harder your temps are still low. — Dan
OK, not good!

Are you sure your fan is OK? Have you tried a second one?

You'll need to take the logic board out to inspect the back side for liquid damage around the SMC logic and/or damaged/missing components.

Do you have the skills and access to the needed parts to replace damaged or missing components? If not it might be easer just replacing the logic board. — Dan
@danj okay replacing logic board is too expensive..I will buy a new fan and test smc logic component with tester..if result is no good..I will say goodbye to my macbook..thanks anyway — jade
I would install this app to help see the thermal load and what the fan is doing TG Pro the free version should offer enough info. — Dan
thanks for your reply, but thre are 5v and 3.3v out in the fan connector of logic board. Does this mean SMC is not the issue? — jade
@jadelyly SMC doesn't create voltages, it just uses them to modulate signals. I can't say what's wrong without testing and in the end it doesn't really make a difference..does it ? — arbaman
@jadelyly - Post a snapshot of TG Pro here for us to see.

These fans have a feedback system (tachometer). Measuring voltages doesn't tell you much unless you understand the logic thats controlling the fan. — Dan
@danj fan diagnostics reauire a registration. is there any way to use this function with trial licesnse? — jade

oldturkey03 @oldturkey03 Rep: 784,3k 1,1k 894 2,3k · Answer 1 · 2019-09-28T13:37:52-07:00

oldturkey03 @oldturkey03

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Publié: 28 sept. 2019

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@arbaman @jadelyly how about removing the fan connector and temporarily connecting test cables from the connector to the fan without the motor controller. Just place a jumper from ground to ground and power to power (5V). If the fan comes on you will know that there is power to the fan. Not turning on would then lead toward an issue with the motor controller circuit (my prime suspect;-)

SSM3K15FV

I added an image of the circuit so I had to make this an answer but should only be treated as a comment.

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MacBook Air 13" mi-2012

A1466 cooling fan stops working but works if external 5v is on.

Update (09/27/2019)

Update (09/26/2019)

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