Macbook Air - 2018 - A1932 - 820-01521-02 - Bootlooping if Power Button Connected

[reessi]

Hello,

With the power button connected it either boot loops with the apple logo or no display but the charging meter shows it looping on charging every few seconds.

No corrosion any where!

Tried a replacement power button off ebay and the same.

Very occasionally it will work with the power button connected!

Same results with or without the battery.

Can it be a fault with the Audio board or the mainboard?

The touch Id assembly connects through the Audio board first then to the Mainboard.

Flex cable from Audio board is in perfect condition..

Any ideas what to check?

I checked reading across both power button tactile switches on the 2 assemblies I have and both the same:

If RED on Ground side of switch then 1K,
If BLACK on Ground side then O/C.

I find that a bit strange? Is there a diode in there?

I checked the components outside the button on the flex but none connect to the switch apart from Ground obviously.. So they must be for the Touch ID.

I checked for shorts all over the Audio board but none.

I'm going to look for the schematics now but I doubt they have the Audio board or Touch/Button Assembly in there.

Also it is strange that every now again it works! - If there was a short it wouldn't magically un-short itself.

Many thanks - Simon.

[gonw]

I've got the same issue, the fault started with the battery indicator not showing charging when plugged in, took it to the apple store and he turned it off during an update now its the boot loop that you have. just started to go through the board view and schematics.

[mon2]

Apple Store moron that turned it off during an update. There is a reason the procedure notes to not power down / interrupt the installation.

Try to boot using internet recovery. See if the boot loop stops.

[reessi]

My issue was only related to the power button, sounds you like you had a charging issue and now you have the boot looping because the update was interrupted like mon2 has said.. OS can be corrupted interrupting it..

After re-installing you can then address the charging issue if still existing..

I never figured out he issue.. It would always boot loop with the power button so I ordered another for testing and it booted but then I put the old one back in to test and strangely that one worked! I was hoping to meter out the flex on each button to see if a difference but it kept working.

My friend asked me to leave dis-connected in case it came back, button is not needed for normal operation and he never used the touch id. Macbook self boots up on USB C connection. Button only needed for touch id and forcing off if crashed.. It hasn't crashed so far and you can just wait over night for battery to die if that happened..