2.3GHz, 2.6GHz, or 2.7GHz quad-core Intel Core i7 processor (Turbo Boost up to 3.7GHz) with 6MB shared L3 cache.

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Component Identity required please!

My macbook retina won't turn on...

I tried to reset NVRAM and SMC but nothing.

I tried to replace the battery but still nothing.

when the mac is charging, the entire logic board is cold except the component in the red box.

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I believe it is inductor (R36 219 CCF ) , I have not been able to find more information and I do not know where to find the replacement.

can anyone help me?

I think it may be a problem for that component.

I accept any other suggestions to fix my problem and turn my macbook back on. ;)




component L7520

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Answered! View the answer I have this problem too

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@oldturkey03 - any ideas on getting the part?


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The inductor won't be the reason why it is turning on; you can see MacBooks with rusted inductor casings and they will still not need replacing. Measure voltage on both sides of this inductor, it is simply passing voltage through it. If you get voltage one side and not the other, then there is an issue.

If you are getting no volts on both side, the CPU is not turning on, since this is one of the voltages required to power the CPU. This component has no pathway to ground, but it may have 15ohms+ resistance to ground, since the CPU has a low resistance to ground. If it has a dead short, then the CPU is probably dead.

If you are confident in replacing the soldered components on the logic board, find the board number (bottom left of logic board) and Google for schematics and a board view for that, and I can guide you. If you have never done this before, and have no intention of potentially making the issue worse, take it to a 3rd party repair company who specialises in logic board repairs and they will check this out.

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Thank you for the reply!

At this time I can not do the measurements, as soon as possible I communicate the results.

with reference to the diagrams:



the inductor is the L7520 (page 66 in the pdf, arrow in the image on "original question"), are there other components that I can check?

the inductor's characteristics are: 0.36UH 20% 36A 0.00108OHM but i'm not likely to find it, any suggestion?


Without being able to take measurements I can't direct you; we would both be guessing. The inductor is going to be working fine. If this was bad, the fan would spin but it wouldn't actually chime and boot (which happens when the CPU is not being told to turn on, but everything else is).

Inspect the board carefully, get a multimeter and check the power rails on the power aliases page of the schematic (G3H, S5, S4, S3, and S0, in that order)


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I’m not sure if the inductor is the root issue here. This maybe more a signpost (symptom) of your power issues.

I would review the schematics and trace out the power rails to see what is not getting power and see why this inductor is getting to much current (short to ground?)

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"(short to ground?)"?


I’m guessing!

You’ll need to trace it out. Inductors tend not to get high current (cause of the heat) which is why it’s possible it’s pathway has a short to ground.


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Jack_T will be eternally grateful.
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