MacBook Pro A1949 - no Power on

[MarioGL]

Hello Guys,

I have a MacBook Pro with four Thunderbolt slot's, it's impossible to turn on the Mac. I brought my Mac to an authorized service center in my hometown. The told me that repair cost are approx. 1000€.
I got my Mac with a disassembled main board, and detected a short circuit on the board.
With an USB-C measurement device, I found out that the power supply is only at 5V with approx. 200 - 400 mA.
I attached a picture of the board, there are two red marked areas, at the coils, the white part (is this a fuse?) and at all of the capacitor's NE CN7 is the short circuit to GND.
I downloaded the .brd file and the shematic for the 820-00850 board, I'm not able to open the .brd File in Eagle or KiCAD, there is an error written in the first line of the file.

My further plan to detect the damaged part is:
Inject for example 1.5V and a maximum current of 200mA at one of the coil's, check the board with a thermal camera to find the part with the highest heat.
If this is a capacitor or something else, with no letter's on it, how can I find out what spec this part have?
Has someone a working File for this board?

I'm no expert in electronics, I only have some basic knowledge.

BR
Mario

[mon2]

Re: MacBook Pro A1949 - no Power on

No, do not inject any voltage onto the coils!!

Wait till more details are known about this logic board.

If you inject the wrong voltage and the cpu vcore mosfet is leaking, the soldered bga cpu will be killed for sure.

Yes, white part is a fuse. Check the resistance of the fuse. Is it still conducting?

Have you been able to load the board view file?

You need a boardview file viewer. Try the one from @Piernov available under his signature on this forum.

I can also link another upon demand.

Next, have not checked the schematics yet but each usb c connector is linked to a usb type c controller called the 'ACE controller'. Often they are CD3215 part number.

Each CD3215 must function before you can have the 20V power delivery contract enabled.

Do you have hot air tool? Tweezers? Multimeter? Patience?

[MarioGL]

Re: MacBook Pro A1949 - no Power on

Thank you for this information.
I measured the fuse, the fuse is fine.
I had no chance to load the file.
I will check the viewer tomorrow.
How can I Check the usb c controller? I was able to find the controllers and they look ok.
Yes, I have all these tools and patience.
Is there a other posibilty to find the issue on this board?

[mon2]

Re: MacBook Pro A1949 - no Power on

Yes, review the following webpage:

https://logi.wiki/index.php/CD3215_Bootup_Sequence

Recommend to source a usb type c meter. I think the one we use is the tc66c from RD on AliExpress.

The first step, aside from reading the above wealth of knowledge, is to measure the voltage on each LDO rail of each cd3215. This is important to know that the controller is functioning.