No Power A2337 MacBook Air 820-02016-A - 5V - 04 Amp

[palmtree]

No signs of liquid damage. No fluctuations, steady at 5v .04amps. I do have a good working spare board to compare to if needed. Have schematic. Would corrupt firmware cause a reading like this? Where do I start?

 

[2informaticos]

What about PPBUS_AON and 3V8_AON?
Do you get correct LDOs for U8100 and U7700?

 

[palmtree]

I get 12.3v on PPBUS_AON and 3.8v on 3V8_AON. I dont know how to check ldo on U8100 and U7700. Also S2 rails seem missing, I dont get any voltage on PP5v_S2 and .38 on PP3v3_S2_UPC

 

[2informaticos]

Look at page 34, U8100 (SYM 3 OF 6); and 29, U7700 (SYM 2 OF 4).
Of course, you don't need to check "NC" marked lines.

 

[palmtree]

Look at page 34, U8100 (SYM 3 OF 6); and 29, U7700 (SYM 2 OF 4).
Of course, you don't need to check "NC" marked lines.

Nothing is correct, C8314/C8315 both read 3.8v, C8321 reads .62v, etc.

 

[2informaticos]

All LDO outputs have correct voltages?
Checked on PMU slave too?

 

[palmtree]

Should C8321 read .62v?

 

[2informaticos]

Not sure about that AVREF voltage; compare with working board.
But do you get all other correct LDOs?

 

[palmtree]

Yes I do

 

[2informaticos]

Then the machine should be recognized into DFU mode; check that.