MBA A1466 (820-00165-A) 2017 has high fan spin and hot GL3219

[Gabr]

Hi All,

I have a problem with a Macbook Air from 2017 (820-00165-A), after 10 seconds the fan spin starts to rise and reaches maximum speed relatively quick. I have checked the usual culprits like U5800 and U5620 camera connector. I don't see any water damage anywhere, but this laptop has been attempted to be repaired before. (a screw was missing).

I also tried a reflow of the SMC without success.
Trackpad also looks fine.
My main question at this point is I notice that gl3219 (U4500) gets quite hot relatively quickly after start-up going over 40 degrees celsius even reaching 50 degrees.
Is this normal? Usb ports work fine and I don't see a relation with SMBUS_SMC_1_S0_SDA, so I am in doubt if it even matters.

TG Pro tells me there is a potential problem with the optical drive sensor, which I don't understand.
Any help would be highly appreciated!
TIA

[mon2]

Try a PRAM reset. After a battery has been removed, the fan spin behaves like this. Hold down the attached keys on a power on and wait till the computer chimes 2 times, then let go.

[piernov]

Post screenshot of HWSensors https://bitbucket.org/RehabMan/os-x-...-2018-0915.zip

[Gabr]

See attached.

[Gabr]

Originally Posted by mon2

Try a PRAM reset. After a battery has been removed, the fan spin behaves like this. Hold down the attached keys on a power on and wait till the computer chimes 2 times, then let go.

This didn't help.

[piernov]

Looks the issue is with the "Heatpipe" sensor on the LIO board.

[Askic]

Originally Posted by piernov

Looks the issue is with the "Heatpipe" sensor on the LIO board.

Could you please what this is. Is it sensor that measure temperature of air flow from the heat sink?
Is it shown on the schematics?

[Askic]

Originally Posted by Gabr

Hi All,

I have a problem with a Macbook Air from 2017 (820-00165-A), after 10 seconds the fan spin starts to rise and reaches maximum speed relatively quick. I have checked the usual culprits like U5800 and U5620 camera connector. I don't see any water damage anywhere, but this laptop has been attempted to be repaired before. (a screw was missing).

I also tried a reflow of the SMC without success.
Trackpad also looks fine.
My main question at this point is I notice that gl3219 (U4500) gets quite hot relatively quickly after start-up going over 40 degrees celsius even reaching 50 degrees.
Is this normal? Usb ports work fine and I don't see a relation with SMBUS_SMC_1_S0_SDA, so I am in doubt if it even matters.

TG Pro tells me there is a potential problem with the optical drive sensor, which I don't understand.
Any help would be highly appreciated!
TIA

I had similar issue except in my case 4 different sensors show 128 deg C. I also tried removing web cam wifi etc but that did‘t help.
Workaround was to install macs fan control app and to set control fan to automatic, to look for example cpu proximity between 20 and 80 deg C

[Gabr]

Originally Posted by piernov

Looks the issue is with the "Heatpipe" sensor on the LIO board.

That would be a bummer since I replaced the IO board a little while ago.
The PPBUS voltage at 8.3 looks a bit low. I notice however if I plug in the charger it goes up to 8.6v

Unfortunatly I don't have a schematic for the io board.

[Gabr]

Originally Posted by Askic

I had similar issue except in my case 4 different sensors show 128 deg C. I also tried removing web cam wifi etc but that did‘t help.
Workaround was to install macs fan control app and to set control fan to automatic, to look for example cpu proximity between 20 and 80 deg C

Thanks for hint, but when fan spin is high at startup I think usually the CPU is also throttled back. So fan control is not really a solution.

[piernov]

Originally Posted by Askic

Could you please what this is. Is it sensor that measure temperature of air flow from the heat sink?
Is it shown on the schematics?

Yes. It is on the LIO board schematics, but that's not available for this LIO board. The 2012 one is available, it's slightly different but it also has this temperature sensor connected to the SMBUS.

[Gabr]

I have removed the thermal sensor (u4730) from the lio board and started the laptop. The heatpipe then shows 128 degrees. Which is the same as before.
This gives me the idea that its not the sensor that is the problem but the signal doesnt arrive at wherever it needs to be.
I am unable to figure out where this is pick up on the main board.
Looking at the flex cable I see no indication that it has an issue, maybe it does tho..

Any thoughts/help is highly appreciated

[piernov]

A sensor that does not communicate because it has a problem, because there's an issue on the communication bus, or because it's missing may well show the same behaviour. No conclusion can be drawn here, but for sure it must be present on the board to work and during troubleshooting.

Can be caused by anything from a bad sensor, bad DC-in FFC connector on either board, bad DC-in FFC, bad pull-up on the SMC "2" SMBus, an issue with the SMC, a broken trace…
Just need to take some measurements and try another DC-in board and FFC to exclude that possibility.

[Gabr]

I will order a new FFC, and check the pull up SMC "2". Thanks for your posts Piernov in this thread so far.