Apple MacBook Pro A2442 / 820-02443 / 5.21V 0.03A

[zeydullak]

Hi guys,

We have Apple MacBook Pro A2442 and the laptop don't charge. We checked all ports with USB-C meter. All ports uses same volt and ampere (5.21V 0.03A). We removed the Logic Board from the laptop. We inspected the Logic Board and could not find any visible damage.

 

[zeydullak]

I need your help in this situation to move forward and to troubleshoot the issue. Please advise what to check. Thank you. See attachments as well

 

[2informaticos]

Laptop doesn't charge, or doesn't turn on at all?
Please post accurate information.

With 5V input, I expect a non-working machine; not just not charging...

 

[zeydullak]

Hi,
Sorry for inaccurate information
So laptop doesn't charge and doesn't turn on at all
There are 3 USB-C ports and all of them use 5.21V 0.03A

 

[2informaticos]

Same behavior on Magsafe 3 port?

Post PPBUS_AON and 3V8_AON voltages.

 

[zeydullak]

Yes the same behavior on Magsafe 3 port. Voltages for PPBUS_AON and 3V8_AON missing. Please advise what to check next? thank you

 

[2informaticos]

"PPBUS_AON and 3V8_AON missing"
Diode mode to ground?

Remove F5200/1 and check C5250 voltage.

 

[zeydullak]

Diode mode to ground is missing as well. It shows 0.0001 mvdc for PPBUS_AON and 0.3 mvdc for 3V8_AON. I put the multimeter on diode mode, put the red on ground and black on element.

Also we tried to remove F5200 from the board but 420C hot air cannot remote it. It does not get melted. It looks like they use very hard material. Please advice how to remove it. How do you do it? thank you

 

[2informaticos]

"Please advice how to remove it"
You don't have 138 degrees solder paste yet???
Allows you to remove it with soldering iron...

"I put the multimeter on diode mode"
Then why did you write "mV"?
Stop doing that; avoid any confusion with voltage checking, please.
What you check in diode mode, is the voltage caused by multimeter injecting constant current on the board!

0.0001 is pure short in diode mode; not a miss at all.

 

[zeydullak]

I did not know there is 138C solder paste. I just ordered and I will have it tomorrow. Thank you for helping me.

I will not write any voltage unit when I measure for diode mode when.

Pure short is the problem. It should not be pure short. So I will remove F5200 and check C5200, post it here. Correct?

 

[2informaticos]

Yeah, good to check that too.
But see first where the short remains, once remove BOTH F5200/1.

 

[zeydullak]

So we removed both F5200/01 from the board. Checked C5200 and C5201 first leg and both of them shows 12.3 vdc. What should we do next? Looks like there is short somewhere. Please advise how to proceed next. Thank you

 

[2informaticos]

"Checked C5200 and C5201"
Do you mean F5200/1?

So the short remains on PPBUS_AON?
I didn't expect that you didn't confirm that yet.

 

[zeydullak]

We checked C5251 and C5250 capacitors. There is voltage.
Yes you are right. Short remains on PPBUS_AON. But there are many elements. How do we proceed to find the next issue. Thank you.

 

[2informaticos]

What is the exact ohm value of that short?

 

[zeydullak]

Resistance is 0.25 MegaOhm between ground and F5200:1 points.
Resistance is 0.11 Ohm between ground and F5200:2 points.

 

[2informaticos]

Check if any big coil gives same 0.11 ohm to ground.
Don't forget LN480/980.

 

[zeydullak]

Hi. Here are the measurement. What do you think about them?

LN480 - 0.31 kohm
LN980 - we dont have this could on the board
L5230 - 0.55 Mohm
L5840 - 0.49 kohm
L5820 - 0.31 Mohm
L5800 - 0.25 Mohm
LF800 - 0.30 kohm
LP800 - 0.23 Mohm

 

[2informaticos]

Then is safe to use voltage injection method.
1V may be good enough to found the culprit.

 

[zeydullak]

inserting 1V means I will connect 1V lab DC power supply to the F5200:2 point and ground line to the ground point on board. Can you tell me how to find it? Using thermal camera? I need your guidance at this step. Thank you.