Macbook Pro A2141 820-01700

[tselectronics]

Hi, everybody,

I have the following problem: Macbook A2141, Motherboard 820-01700. The display isn't turning on, fans are spinning, no image on external monitor. The problem occured while Macbook was turned on.

Voltage is there in all elements except for PPVCCGT_S0_CPU. Current consumption is 1.8A when laptop is turned on. Usually I think it should show 5V and then 20V, this one shows 20V immediately, don't know if this is a clue. Communication between U7100 and CPU is lacking (not sure if this is a problem or not, when does it have to be there).

Please give me some clues on how to proceed. I'm in a dead end!

Thanks!

 

[2informaticos]

First of all, welcome to the forum!

Don't expect iGPU voltage (PPVCCGT_S0_CPU) until Intel graphics gets high load.
What is the CPU core voltage (PPVCC_S0_CPU), after 10-20s?

"The display isn't turning on"
So do you get image on internal LCD?

 

[tselectronics]

PPVCC_S0_CPU voltage is 0.939V

No image on internal LCD, no image on external display.

 

[2informaticos]

Right, I don't know why I have read "is", instead of "isn't"...

0.9V means the board doesn't really boots just stays on.

Try first DFU revive; restore, if no data to save.

 

[tselectronics]

Right, I don't know why I have read "is", instead of "isn't"...

0.9V means the board doesn't really boots just stays on.

Try first DFU revive; restore, if no data to save.

How do I do DFU revive without knowing what OS was present on the Macbook? Can I do DFU revive without needing second Macbook? Slight clarification would be greatly appreciated.

 

[2informaticos]

Normally no need to use exact same macOS in the host (AC2) machine.
Anyway, if think that can prevent DFU to complete, you can try DFU with more macOS versions in the host MacBook.
Using USB versions, like Mojave, Catalina, Big Sur.
Just be sure to use the dedicated DFU port on the target machine.

Read this thread for more information and follow the steps from the linked tutorial.

HOW TO collection

I hope this "How to" collection will help our members. I will possibly modify this post in time, if updates available. Trigger SMC_ONOFF_L (PMU_ONOFF_L): It reffers to simulate power button function, when the keyboard is not connected. We need to do this when we work with the board...

boards.rossmanngroup.com

Do not quote an entire post, visible few centimeters above.
Please, maintain forum aesthetic...

 

[tselectronics]

Sorry about the quote.

I tried DFU mode (Host is M1 Macbook Air 2020). It starts installing and then with no error just stops and gives me a Lock Icon. Nothing more.

Any further assistance? I am desparate at this point.

 

[2informaticos]

Padlock sign at the end denotes DFU completed without errors.

CPU core voltage, still stuck on 0.9V?
It should drop at 0.6V aprox when machine really boots (after 10-15s).

 

[tselectronics]

CPU core voltage is still 0.9V. Interesting observation is that the fans start accelerating towards approx. 100% after 20-30 seconds.

 

[2informaticos]

Test with external monitor, disconnecting internal LCD.
Also try known good trackpad board/flex.

 

[tselectronics]

No image on external monitor, even after disconnecting the internal LCD, tried good trackpad, nothing...

Macbook turns on by itself (can't even shut it down without it starting immediately after), fans go to 100% after a while, that's it for now.

 

[2informaticos]

Then fans issue is not caused by camera/ALS.
Probably trackpad board/flex problem.
But that shouldn't prevent video to appear.

Possibly bad CPU...

 

[tselectronics]

That's what I thought. Thank you so much for your help! Learned many new stuff. Keep up the good work!