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[SOLVED]820-000239 (A1706) No power

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ALB-Repairs

ALB-Repairs

Member
Hi.
Got a painfull one here. Would love a bit of help.

It only had small signs of corrosion around 1 of the USB controllers.
Cleaned off thinking 'probably going to be all good after an ultrasonic'

its not, i cant seem to find any power at any part of the board. Im using an 87w USB C apple charger thats brand new (tested on a a1534 macbook and charges it fine)

I found a small inductor with very low resistance to ground 2ohm's. It doesnt look to be part of a high amperage circuit.
If anyone has one of these boards could they measure the power to the inductor and its resistance to ground?

Will attach pictures in the next post.
Thanks
 
ALB-Repairs

ALB-Repairs

Member
Yeah. thats what i thought, and it would make sense that i cant get any power anywhere without pp3v42 (or whatever variation these use.) i injected 1v into it but because its 2ohm and not 0ohm it doesn't pull enough current at 1v to heat anything.

I lifted the inductor and checked both pads for resistance, 30k on one side and 2ohm on the other, Im thinking of injecting about 3v3 but dont have the confidence as its a customers and im assuming they have important data on it. Dont wanna start injecting higher power into it and risk damage.

I could try using hot air to pinpoint it. Even if i do i doubt it will be a component i will be able to get hold of. These newer systems are killing me.
 
D

dukefawks

Administrator
Nono, unless you have another machine to compare don't do anything. Look around the SMC, that is where 3V42 bus can easily be found and see if there is 2 Ohm to GND there too.
 
ALB-Repairs

ALB-Repairs

Member
Ive managed to find it near the SMC (although there isnt that many components around the SMC on this model.)

Ive also found it on the trackpad keyboard flex connector. I assume you are right in guessing pp3v42.
 
ALB-Repairs

ALB-Repairs

Member
Found a shorted cap near the main corrosion area (next to a USB C controller chip). It was indeed PP3v42 (confirmed by testing the SMC_LID sensors)

Now up and running again, it has a stained LCD but at least the customer has his data :)

Mark as solved please
 
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