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The March 2015 update of Apple's 13" MacBook Air features fifth generation Intel Core i5 and i7 processors, resulting in slightly increased performance and battery life.

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Won't turn on (except very rarely)

Hello everyone. I have a MacBook Air A1466 with a very strange behaviour. I've tried a lot of possible solutions I've found here but nothing works. The device is not mine and I only received it a couple of days ago, so past behaviour descriptions might not be as reliable. Here's the situation:

Apparently some time ago the device started having some issues when booting. At times it would simply not turn on, neither plugged nor unplugged. Trying again some time later it would turn on and then work perfectly for some time, botting and shutting down, etc, then randomly the issue would reappear. It was sent to 2 different repair shops, one changed the battery (not necessarily related, but it was due for a change anyway). Both didn't find anything, claiming it worked fine while they had it.

The problem started happening more often, until the owner decided to get a new macbook and they gave this one to me. The first time I tried to power it on, it booted fine, got to the lock screen, I entered the password and it started filling a bar, like it was upgrading something. Right before the end the computer shutdown, and it wouldn't turn on again. Since then I've managed to turn it on twice more with the exact same result (lock screen, entered password, bar filling, sudden shutdown). When plugged, charger turns green briefly then stays orange.

I've completely disassembled everything: removed battery, speakers, main board, I unplugged every connector to check for corrosion. Removed the trackpad too. The insides look pristine. I did find some really minor blemishes and just a tiny bit of oxide on the outside of a couple of the biggest resistors, but nothing on the board or paths.

When power button is pressed, sometimes the fan will spin for a bit then stop, other times it won't turn at all. Same when power is plugged in.

So far I've tried:

Unplugging and replugging the battery and power cord (like a thousand times each).

Cleaning the power socket.

Unplugging components and trying to boot up without them, one by one and in all combinations: SSD, speakers, track pad only, whole keyboard assembly, screen, cooler fan.

Checking wheter USB ports can charge something (they can't)

The shift+option+cmd+power combo to reset SMC. This appears to do something, as the led in the charger cable turns green for a moment when releaseing the keys, then turns back orange.

I really don't know what else to do. It's so odd that the machine is definitely not bricked as once in many many tries, it does turn on. Next time it does I'll try NOT entering the password, and just leaving it at the lockscreen to see if it'll stay on.

I haven't done any voltage testing as I wouldn't know what to test, but I do have equipment to do it if necessary.

Any help will be greately appreciated.

Update (05/24/24)

Quick update: I disassembled everything down to the main board and did a full visual (magnifying lens) inspection. I found tiny bits of grime and specks of dirt, but nothing relevant. During one of many test, the fan started spinning and it actually stayed on for quite some time (maybe 30 seconds or more). I tried that a few times and the same happened, so I started reassemblying everything, to see it the machine would boot, but about halfway done it stopped doing the fan spin when plugged.

I did some very basic voltage testing: when plugged in I do get 15V and 3.4V on the MagSafe connectorr (on the board side). There's also 8.5V on the big inductor accross the board, as it should be, and the fuse right next to it does have continuity.

Any suggestions or ideas of what to try next?

Update (05/26/24)

Trying to measures voltages around the board (I'm waiting for some precision multimeter tips to arrive, since the ones I have are too big to reach tiny components) I've noticed that I do have voltage on the 8.5V line and the 3.4V line (I'm not really familiar with the layout, but I do measure those voltages on several places), but there's no 5V anywhere, and as far as I know, there should be a 5V power line? Does this info help anyone more familiar with the board to point me in the right direction as to what to test next?

Update (06/01/24)

I decided to strip the computer again to the bare board and throw it into an ultrasonic cleaner. Then spent some time drying it with hot air, using contact cleaner on some spots, scrubbing it with a brush wherever I saw the tiniest speck of dust or rust. I reassembled everything and it booted once. I realized I forgot to connect the keyobard, so I did, and now the computer doesn't boot. Disconnect the keyobard, and still doesn't boot.

Left it unatended for a couple days and..... now it boots. Consistently. Every time. Keyboard and mousetrack don't work, only the power button, BUT keys actually do work because I can do the SMC reset (shift+option+alt+power) and it does reset, to the actualy keys work. It's just that keyobard is not being recognized by software once the computer boots.

I'm using an external keyobard and mouse with an USB dongle and I am now updating the OS to see wheter that fixes it.

Ответ на этот вопрос У меня та же проблема

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If you can install then gem of an App CoconutBattery take a snapshot of the Apps main window and post it here. I'm suspecting your battery is shot.

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You mean install it on the MAcbook? Impossible, it won't even boot... The battery is supposed to be new, it was changed by the latest repair shop. Also, even with the battery disconnected, the macbook won't turn on.

Thanks for the reply!

из

@lberstein - Lets give this a try with the system back together without out the bottom cover disconnect the battery, now carefully place the system on its side with the MagSafe connection up. with nothing connected press and hold the power button for a good 20 secs to fully discharge the logic board (hard SMC reset), now plug in the MagSafe charger the cord LED should be Amber in color and the system should spontaneously boot up. Let it do so and then do a clean shutdown. Disconnect the MagSafe charger and reconnect the battery and then the charger once more. Is the system booting up spontaneously? Did the system continue to work the second time?

из

I tried what you suggested. Fan doesn't spin and computer won't turn on. MagSafe LED goes green as soon as plugged, then after a few seconds it turns to amber.

Keeping the power button pressed doesn't change behaviour. If I do the "smc reset" combination (control+option+shift) it flashes green again, then back to amber.

из

@lberstein - An Amber LED is the battery needs a charge and often the battery is not able to hold a charge as well.


So let it sit for the day it should get to Green, if not it’s time for a new battery given its age.

из

I left the MagSafe plugged for a few hours and the LED turned to green as expected. Again, the battery was replaced only a few months ago. The issues with the computer appeared before the battery replacement, and have continued with the new battery. Also, even with the battery disconnected, the computer won't boot up, so the issues is definitely not the battery.

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