Strange power behaviour - MacBook Air won't power on normally - SMC?
This problem is afflicting my mid-2013 MacBook Air Core i5 1.3GHz
The MacBook Air will power on *only* when no battery is connected, and then it does not power on when the power button is pressed. Instead it powers on when a power supply is connected - when doing this with the bottom case removed the fan starts for a few seconds, stops, starts again for a few seconds, stops, and then on the third attempt the MacBook starts up. Without a battery connected its behaviour is then otherwise normal - everything works.
When a battery is then connected nothing works - the MacBook will not start. Connecting the power supply - enough to make it start when there is no battery attached - then does nothing, and pressing the power button also makes no change. However pressing the power button momentarily makes the charger LED switch from orange to green. It then switches back, and the machine does not boot.
I have reset both SMC and NVRAM multiple times, and tried all of this with two different batteries - and it is the same all the time.
Apple Hardware Test gives the error PPT004 “battery requires service”, but the battery is new.
I hence presume this is a problem with the SMC and there is no option other than to take it for a professional repair?
Any assistance here would be most welcome.
UPDATE 1 - in light of Dan’s comments below, here is the screenshot from Coconut Battery
UPDATE 2 - @danj OK, so I have tested and re-tested this, and it is *not* a problem with a faulty battery. I ordered a second hand Apple battery and this exhibits *exactly* the same issues as the two other batteries I have tried, and with the Apple battery as well calibration makes no difference.
This problem is either connected to the SMC or the charging circuits of this MacBook Air.
The closest equivalent problem I have found is this Strange Power Supply Behaviour faced by @karthikrr and diagnosed with @arbaman. I have also tried following this Does not power on after SMC reset, will on SMC bypass.. but that SMC bypass route does not work either.
So we need to look elsewhere to solve this.
First, the I/O button does respond to pressing it - when pressing it when the MagSafe is connected, the LED on the MagSafe switches from orange to green for a few seconds, then back to orange. Also if you do get the computer to boot (by disconnecting the battery and starting it by plugging in the MagSafe) and then when it is running you press the I/O button, the machine goes off *immediately* - it does not give you the Restart / Shut Down menu as it should. So there is something odd there.
The question then is what I could try next? Apple Hardware Test gives the error PPT004 saying the battery is suspect, but we now know that is not (at least not the battery itself) the case. Is there some way I can diagnose whether the SMC or the charging circuitry is faulty?
So - a couple of months on - I managed to source a new logicboard for the MacBook, installed it, and everything works perfectly. The answer to @danj is clear - the fault is with the logicboard. I have now sent it off for repair, and we will see what the company says - I will post any conclusions here too.
An inspection of the logicboard shows what looks to be light corrosion as shown on the pictures here: