MBA won't boot after shut down

Hi there,

I have a weird issue. I have a MBA A1465 (Early 2015) which has developed an odd problem. If it shuts down, it will not reboot unless I take the back off, disconnect the battery for a few moments, then reconnect. If it is running, and I restart it, everything is fine. The issue only happens when it shuts off completely.

When I am trying to reboot it with the 'on' key, the indicator light on the charger will change colors as the on key is pressed, then will change back when released.

I have reset the SMC (which appears to work)- no boot afterwards.

I have done a PRAM, but nothing happens.

I have started it up and done Apple Diagnostic... no issues were found.

I have repaired the drive with Disk Utility and Disk Warrior - nothing.

I started in verbose mode and reset the NVRAM with a reboot.

I wiped the drive and updated it.

I swapped the trackpad cable with a known good one, I swapped the battery with a known good one.

My gut feeling is that it is the SMC chip on the logic board. This logic board was replaced by Apple last spring. I would like to rule out any other reboot issues before I send it in.

So... any ideas?