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Mis sur le marché en juillet 2018, le MacBook Pro 15", modèle A1990, est muni d'un écran de 15,4 pouces avec rétroéclairage LED et technologie True Tone et d'un processeur 6-core i7.

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MacBook Pro A1990 doest turn on

Hello ,

I just bought a broken MacBook Pro A1990 , year 2018 board number : 820-01041A.

The previous owner of the MacBook told me that a little bit of water touched the left hand USB C port and the computer shuts off. He took it to the lab and they say that the CD3215C is bad and need to be replaced but they are not good at this .

Anyway , I bought this computer and start examine it , here is what I found :

  1. All the USB C ports are stuck in 5V / 0.4A ( battery unplugged )
  2. PPBUS_G3H is present 12.3V
  3. PP3v3_G3H is present 3.3V
  4. PP3v3_S5 is 1.3V
  5. PP1v8_G3S is missing

I am not familiar with the power sequence of a MacBook Pro.

So, anyone can guide me what do to next ? can it be a problem of T2 chip ? I thought that if there is a problem with the CD3215C so only the damaged chip will show abnormal behaviour .

Thank you for your help.

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I would jump over to Louis Rossmann YouTube channel to see how he deals with CD3215 chip and then how to deal with missing PP1v8_G3S

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Hey Dan , already did it.

Louis says that a faulty CD3215 will be stuck on 5v while good CD3215 will be in boot loop mode. In my case all the CD3215 are stuck at 5v , this is why I don't think that the problem is with the CD3215 chip , but maybe something else which connect between those four chip beside of course the T2 chip.

par

@Nitzan Oz - Get your schematics & board views lined up and glue your eyes to a good microscope to trace out the PP1v8_G3S circuit as you likely have a break or an open line.

par

Thanks Dan ,

tell me maybe do you have the power sequence of this MacBook, when the PP1v8_G3S is turning on ?

Moreover, I viewed Louis video again and it seems that sometimes CD3215 is faulty even if it doesn't boot looping and thermal camera can assist.

par

@Nitzan Oz - I would focus on what Louis offers on his site as he and his team go much deeper than I do. I only dabble at this level these days as my arthritis in my hands makes it hard.

par

Hey @danj ,Thank you for your help , and take care :)

par

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Nitzan Oz sera éternellement reconnaissant.
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