A2141 MacBook Pro not powering on

[Coder]

Hello there,

I have a A2141 MacBook Pro with board 820-01700-A that doesn't power on.

I had recently reinstalled the operating system. Then out of nowhere it didn't want to turn on anymore.

I don't have much knowledge repairing mac boards other than placing one test lead on ground and the other one on each component, and replacing them, etc. I don't know if this is the proper way on testing caps and other coils on mac logic boards.

Now, long story short, I placed the board under my thermal camera to locate the short or the fail. But I cannot visualize the component with the short since almost immediately the heat circle covers about ten components at the same time.

So I decided to measure one by one. So I seted my multimeter to check for continuity on all heat circulated components shown on my thermal imager.

They are all capacitors, but they all emit continuity on both sides when testing them. Does this mean they are all shorted?

Then I changed from continuity measurement to diode measurement, and each capacitor measures 10v but in the diagram the measurement is: 20UF 20% 2.5V X6S-CERM 0402 C782

I will appreciate suggestions and tips on how overcome this problem.

Best regards

 

[2informaticos]

First of all, welcome to the forum!

The heat may come from opposite side; there are T2 and PMU placed.
You should check diode mode to ground on all the coils around U7800.
Don't forget to remove charger and battery first.
If no short, then connect charger and check voltage on same coils.

Do you have USB-C meter?
That helps, showing the power ports behavior.

Be aware, this board requires 87/96W charger.

 

[Coder]

"First of all, welcome to the forum!"
Thanks

" The heat may come from opposite side".
There are no components on the other side.

" You should check diode mode to ground on all the coils around U7800."
How do I do this?

" Don't forget to remove charger and battery first."
As you sw in the pictures, the boards is out.

I feel down, I was hoping you could answer me all my comment, or at least part of it.
What about the measurement of the caps I mentioned it?

"Do you have USB-C meter?"
Yes, I have a small one.

" Be aware, this board requires 87/96W charger. "
Charger is 96W that should not be a problem.

 

[2informaticos]

So, what shows your USB-C meter?
Check all USB-C ports, in both ways.

The caps must be connected to above mentioned coils.
That's the reason I asked you to check in diode mode; L7806/10/12, etc...

Read here about how to check in diode mode.

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

 

[Coder]

USB-C meter is showing: 20.2V 0mAh => 0.03 A

"Read here about how to check in diode mode"
Which is why I still thinking that you did not readed my post #1

 

[2informaticos]

Yeah, did you read this?
"The caps must be connected to above mentioned coils.
That's the reason I asked you to check in diode mode; L7806/10/12, etc..."
Let see then if you really have short on the caps.

 

[Coder]

that's ok sir, you do not want to read my post #1
but this is what i posted:

"
So I decided to measure one by one. So I seted my multimeter to check for continuity on all heat circulated components shown on my thermal imager.

They are all capacitors, but they all emit continuity on both sides when testing them. Does this mean they are all shorted?

Then I changed from continuity measurement to diode measurement, and each capacitor measures 10v but in the diagram the measurement is: 20UF 20% 2.5V X6S-CERM 0402 C782".

i believe the caps i tested are short.
i even asked if that was the right way of testing them, but it was easier to tell me to test them in chinese.

 

[2informaticos]

No idea how many times I need to repeat, until you decide to post the diode mode readings.
The red circled caps are almost all connected to L7806; so dificil to get diode mode reading there?

As per schematic, PPVDDCPU_AWAKE must be in range of 0.625-1.06V.
In a good board, L7806 should get 0.018 reading in diode mode.
Multimeters beep until 0.055-0.075, depends the model.
If any beep means short for you, that is a VERY WRONG assumption.

I cannot compare a good reading with your board (on L7806), because you continuously refused to post such value...

 

[Coder]

L7806 ..It took me a while to locate it even though it was right there. Anyway, testing L7806, with no power going into the board I get a reading of 19.22 K Ohm and keeps going up and up 37.17 K Ohm, etc. it does not stop, it is not an stable reading.

As for the caps, as I mentioned on post #1, I get I reading of 10v. which on the diagram all of them shown 2.5v

 

[Coder]

" In a good board, L7806 should get 0.018 reading in diode mode."

My bad, in Diode mode, with red lead on board ground and black lead on one side of L7806, I get a reading of: 0.786

 

[2informaticos]

You've said circled caps get continuity between their pins.
I supposed that means you've got beep.
That is impossible with 0.786 reading in diode mode.

Be aware, some multimeters require to pulse a SEL button to change from continuity (beep) to diode mode.
I don't understand the mention of 10V on the 2.5V caps.
When connect the charger, do you get voltage on these caps?
In fact, check voltage for all coils near U7800.

 

[Coder]

" You've said circled caps get continuity between their pins."

What I meant was.. if you look at the picture I posted on post #1 Image_2.JPG
On all those caps, with red lead on board ground and black lead on any side or even both sides, I get an unlimited beeping. but I mentioned that I do get this beeping if I set the multimeter in continuity mode. I guess I was doing this test the wrong way.

"I don't understand the mention of 10V on the 2.5V caps."

Correction:
With power in, I do get 0.741v on six of then, and 0.811 on one.

" check voltage for all coils near "

Correct me on this one, what coils look like?

 

[2informaticos]

"L7806/10/12, etc..."
All coils around U7800.
Just look at boardview and will see lot of small coils surrounding it.
Some of them are connected together; check only one in such case.

 

[Coder]

I had a big incident and could not continue, but am back. Although, on the other hand, going back to review my question, and reviewing your answers, I don't see that you have answered my questions well. I feel like you use a translator or something. Am I correct? If that is the case, let me write to you in spanish then.

En varias ocasiones te pregunte si la manera correcta de medir que yo he estado utilizando era correcto o no. Te explique que colocaba la punta del multimetro positivo en tierra del chasis, y con la punta negativa, las mediciones en cada componente, pero no contestaste. Pero bien, gracias de todas maneras.

Ahora regresando al titulo de esta pregunta, te pregunto.. el multimetro que utilizo es un fluke, y en medicion de diodos, casi todos los componentes al rededor de U7800, todos emiten sonido, es decir, un beep.

 

[2informaticos]

Me defiendo bastante bien en ingles; el español tampoco es mi idioma nativo, aunque me viene mejor.
However, I don't use online translator in the forum.

"En varias ocasiones te pregunte si la manera correcta de medir que yo he estado utilizando era correcto o no. Te explique que colocaba la punta del multimetro positivo en tierra del chasis, y con la punta negativa, las mediciones en cada componente, pero no contestaste. Pero bien, gracias de todas maneras."
I didn't say that is wrong manner; just read this:

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

Note that beep doesn't mean short; some multimeters beep until 055-070.
That's the reason I asked about diode mode readings, not beep.

 

[Coder]

WOW! Man, is it too hard for you to explain things differently? I don't know in which language to ask now. APRENDE HABLAR PENDEJO! o aprende a explicar bien las cosas semejante idiota! eres un hijo de puta!!!

I really do not recommend this forum to any beginner like me.

HOW TO collection
I hope this "How to" collection will help our members. I will possibly modify this post in time, if updates available.

All your answers have a dead end. Let me tell you that you are very lousy as a teacher. I subscribed to this forum because I thought that louis was the one that maintained this forum, otherwise I never would have wasted my time.

I would spend millions of years trying to explain my problem, while you keep saying Huh?

 

[2informaticos]

""En varias ocasiones te pregunte si la manera correcta de medir que yo he estado utilizando era correcto o no. Te explique que colocaba la punta del multimetro positivo en tierra del chasis, y con la punta negativa, las mediciones en cada componente, pero no contestaste. Pero bien, gracias de todas maneras.""
---------------------------------
"Test in diode mode:
Connect positive probe of the multimeter (red) to ground and touch the test point with black probe.
Sometime (rarely) we need to test in reverse direction."
Isn't that the reply of your question???

How much time do you need to post the readings asked you few days ago???
We don't measure sound/beeps here; need diode mode readings in this case.