Macbook air 2015 (00165A motherboard) power issue

[mcnamj70]

My Macbook air 2015 (00165A motherboard) has a strange fault.

When I plug in the charger the laptop immediately switches off.

The battery still charges when off and I can reboot the laptop with the charger connected and all appears fine until I disconnect then reconnect the charger and the problem appears.

Tried resetting PRAM/SMC and even changed the I/O board but problem appears to be on the motherboard so looking for ideas to fault find.

[mon2]

Re: Macbook air power issue

Are you using the official magsafe power adapter?

Remove the battery.

Attach the power adapter. Measure the voltage to ground of each pin of the dual common cathode diode at D7005.

Confirm that you have a stable 3v42 rail that is fed by this dual diode component. This diode will steer the higher of the 2 voltage rails, the magsafe power adapter or the battery to power the logic board.

Confirm the ppbus_g3h voltage to ground.

Post each measurement.

[mcnamj70]

Re: Macbook air power issue

I am not using an original magsafe but it works on my other macbooks fine.


Pin 1 is at 8.6V
Pin 2 19.7V
Pin 3 19.5 V

[mon2]

Re: Macbook air power issue

What is the voltage to ground @ R7012 ?

[mcnamj70]

Re: Macbook air power issue

With the mains connected and the battery disconnected the voltage across is 20.4V

[mcnamj70]

Re: Macbook air power issue

ppbus_g3h is 8.4v

[reformatt]

Re: Macbook air 2015 (00165A motherboard) power issue

I'd be pulling out the board and looking closely at the ISL (U7100) section. If your PPBUS_G3H is 8.4V without battery (should be 8.6V), then this points to the ISL area. Screwy PPBUS_G3H voltages are usually corrosion around pin 1~7 of U7100 and the attached resistors therein.

[piernov]

Re: Macbook air 2015 (00165A motherboard) power issue

Pin 1 is at 8.6V

ppbus_g3h is 8.4v

.

[mcnamj70]

Re: Macbook air 2015 (00165A motherboard) power issue

I re-balled the SMC and now all seems good.

I used 0.3mm solder balls to re-ball and it produced very neat results...much better than any stencils that I have used. It takes a while to place the 157 balls but was well worth it.

The laptop is still running a bit hot so suspect there is still a short somewhere...may invest in a IR camera to investigate further....any recommendations?