MBA a1466 (13" e2015) only boots while plugging in cable

This could be the same issue as: mba a1466 - liquid damage

But want to get another opinion as a I have a few additional symptoms to narrow it down…

Model: MB Air late 2015 13” (a1466 model), 2.2Ghz cpu, 500gb flash drive.

About 2 years ago, my 6-year-old found my MBA, spilled water (thankfully, “just” water) on MBA, which then doesn’t boot, won’t power on. I did the usual stuff of trying to leave it upside down, etc etc.

After a while of letting it dry out, failed attempts & w/ budget restrictions, I closed up the macbook, found a replacement on kijiji and moved on with life.

About 1 year I pulled out the mba from my filing cabinet, opened it up, and plugged it in to see what happens.

—— MBA immediately turns on (without using power button), and loads up to login screen.

I login to mba fine, loads up without any notable issues, trackpad works (both buttons), the laptop will even stay on for a while and I used it for over an hour watching netflix.

After shutting down / closing lid, MBA shutdown and won’t boot at all, doesn’t work on battery or when plugged in.

— Magsafe is AMBER when connected, and when pressing on power button, turns GREEN briefly before turning back to amber.

>>> Over time I’d leave the MBA for a few weeks, eventually retest & it would start the same way —- immediately as I connect magsafe, it boots without pressing the power button, does not work on battery & cannot boot if I shut down.

Last time I was logged in I took a look at the system details and the battery was only at ~211 cycles (I’ve heard they drop out around 600), but I have not yet been able to confirm any water damage of the battery, either.

Last night I finally got around to opening her up and taking a (brief) look, here’s what I found (without removing the lb to look for obvious corrosion/etc):

• Symptoms persist, MBA will boot immediately when plugging in charger (without pressing power button) but subsequently fail to boot after, with or without magsafe connected.
• MBA will not boot at all on battery.
• When pressing power button in the stuck/non-boot state, pressing the power button changes magsafe to green light briefly before turning amber again.
• All symptoms are identical when the battery is disconnected.
• !!! Newest finding —- After disconnecting the battery and retesting, the issue persists — BUT: if I press & hold the power button for a few seconds with magsafe & battery disconnected, and THEN connect magsafe —— MBA boots up & I can get it to start without having to wait at all (previously, I had to wait over 2-3 weeks minimum, otherwise the symptoms persisted & MBA would not boot).

I’ve taken a look at a few schematics and it seems the SMC is (possibly) the most likely candidate, from what I could gather from the schem/boardview.

From what I understand, it seems that the issue is w/ a part that is retaining a charge and preventing boot, until I drain the level to ground by using the power button… This makes sense on my end as leaving the MBA to sit for a month+ would (I expect) have the same results as opening a path to ground using the power button — it’s draining any residual charge.

Based off the schems it appears that power flows to the SMC & there’s a path to ground that’s triggered by the power button.

a) Why does pressing & holding power button help improve the issue (ie. I can boot without waiting) if the powerbutton/path to ground gets completely skipped when the MBA boots? I would think that if I can drain the current to get it to boot again I should be able to get more results using the power button?

It seems like the power button is also involved in the issue as it can be used to improve the wkstn’s state, however is unused when booting.

(If anything as I’m writing this, I’m almost convinced it’s more the power button/keyboard itself…)

Ultimately I’m thinking I’ll want to replace a few parts anyways, but ideally I’d like to narrow down the scope (& cost!)

So far seems like either the SMC, or something just right busted w/ the keyboard which could explain the odd behaviour as well.

Any input is greatly appreciated.

Happy fixing!

Edit: Photo of coconutbattery… I was also unable to get the mac to boot today with the battery connected.