820-00165 no green light on the charger and no fan spin

[mcnamj70]

I am troubleshooting a Macbook Air and the SMC posts a voltage of 8.2V at PPBUS_G3H.

Should I replace the SMC?

Macbook appears dead with no green light on the charger and no fan spin.

[mon2]

Re: Macbook air logic boards 820-3437 and 820-00165 Backlight

1) what is the exact 820-**** number of your logic board ?

2)

no green light on the charger

A key power rail, that is 3v42 is missing. It is this power rail that powers the single wire Dallas / Maxim Semiconductor LED controller and soft-turn on of the power supply. If the magsafe hood led is missing then this power rail is missing.

After you post the logic board #, we can review this power rail but often it is the DUAL common cathode diode that often fails.

Attach your power adapter and measure the voltage to ground of each of the pins on the dual diode that feeds the above regulator.

Post each measurement.

Update - see attached.

1) Check D7005 voltage to ground of each pin.

2) Check the voltage to ground of PP3V42_G3H. Suspecting that this power rail is missing or is very low.

[mcnamj70]

Re: Macbook air logic boards 820-3437 and 820-00165 Backlight

My board is the 820-00165A.

Will check the supplies and get back to you...many thanks for your help.

[mon2]

Re: Macbook air logic boards 820-3437 and 820-00165 Backlight

Well noted. The above schematic is the same on your 820-00165.

Do review the above critical rails. Only if this rail is present will the PPBUS_G3H start to function, etc.

[mcnamj70]

Re: 820-00165 no green light on the charger and no fan spin

Hi,

Voltages measured at input to Diode were 20.2v and 8.2v with 20.1v at output. The PP3BUS_G3H measured 3.43v at output.

[mon2]

Re: 820-00165 no green light on the charger and no fan spin

These are good voltages.

Clean the contacts of the magsafe connector on you logic board with IPA.

Check or replace the LIO cable that mates the main logic board and the LIO board.

If you have 3v42, then the magsafe head led should be lit.

[reformatt]

Re: 820-00165 no green light on the charger and no fan spin

Check SMC_RESET_L and area around U5110. First entry in the repair.wiki for this model. Covers most of these issues, and this specific problem has been covered thoroughly in other threads.

https://repair.wiki/w/A1466_2015-201...9D_MacBook_Air