Macbook 820-00165

[Instafixx]

Hello,
We have a Macbook Air 820-00165 in Dead Condition.

Charger having Green/Orange Light.
PPBUS_G3H at 8.55V

After inspection we found a little Green at U8000. Went ahead cleaned and reballed the IC.

The motherboard otherwise is squeaky clean.
Upon inspection with a working same motherboard we found that there isnt aby voltage at R8177.

I dont know whether i am on the right track here or not.
Please guide.

[Aliseo]

Re: Macbook 820-00165

check PP3V3_S5 and PP5V_S5

[Instafixx]

Re: Macbook 820-00165

check PP3V3_S5 and PP5V_S5

Voltages in these 2 Lines are fine.

There is no voltage at Pin#1 and Pin#2 of L7520.

[mon2]

Re: Macbook 820-00165

Measure the voltage to ground of the EN pin #4 (P5VS4RS3_EN_R) U7501 that is the ENABLE for this power rail.

If this voltage is a logic high '1' then remove all power -> check the resistance to ground of this coil / inductor L7520.

[Instafixx]

Re: Macbook 820-00165

Measure the voltage to ground of the EN pin #4 (P5VS4RS3_EN_R) U7501 that is the ENABLE for this power rail.

If this voltage is a logic high '1' then remove all power -> check the resistance to ground of this coil / inductor L7520.

Resistance on both Pin 1 and Pin 2 is 380 (Meter is set to 2k)

[mon2]

Re: Macbook 820-00165

The first part was missed.

Measure the voltage to ground of the EN pin #4 (P5VS4RS3_EN_R) U7501 that is the ENABLE for this power rail.

[Instafixx]

Re: Macbook 820-00165

The first part was missed.

Voltage Measured. It was 1 as you said it might be.

[mon2]

Re: Macbook 820-00165

1) Remove the LIO cable -> measure the resistance to ground again on L7520. Is it still ~300 ohms ?

If yes, lift up one leg of L7520 and then measure the resistance to ground on each side of the PCB pads for L7520.

Need to know which side of the coil is with the low resistance.

Is it the producer side (U7501 = L7520, pin #2)

or

is it the consumer side (L7520, pin #1) ?

The 300R (300 ohms) to ground on L7520 sounds low to me on this high current rail.

[Instafixx]

Re: Macbook 820-00165

1) Remove the LIO cable -> measure the resistance to ground again on L7520. Is it still ~300 ohms ?

If yes, lift up one leg of L7520 and then measure the resistance to ground on each side of the PCB pads for L7520.

Need to know which side of the coil is with the low resistance.

Is it the producer side (U7501 = L7520, pin #2)

or

is it the consumer side (L7520, pin #1) ?

The 300R (300 ohms) to ground on L7520 sounds low to me on this high current rail.

Removed the L7520.

Resistance on Pin #1 is 399
Resistance on Pin#2 is 428.

Meter is set to 2k Mode.