A2141 820-1700 Running slow, Liquid damage

Ebix

New member
Hello , Im learning how to fix macbooks and i've been trying to work on one, but as i dont have much knowledge i got stuck. And i was wondering maybe you could guide me atleast where should i start from where i am now.

I have this macbook which had hot chocolate spilled on. Let me explain what i have discovered and done so far.

A2141 820-1700 2019 16"

Whats wrong with it :

Running slow (Everything you do takes 10x then estimated time)

Has kernel_task running 1000+% ( Picture 9 )

When booting to safe mode or to recovery at 3/4 shows artifacts on screen then white screen and back to normal everytime ( Picture 6 ).
Sometimes when turning off shows ( Picture 8 ).

Had weird ssd volume split ( Picture 4 ) not sure what caused that but could not delete weird volumes created like 15 of them same random small size ( Picture 7 ). Was giving errors when trying to delete volumes ( Picture 5 ). But managed to sort that with forcing through terminal, now looks all ok.


From visual inspection of the board i have found
Liquid damaged place ( Picture 1 ).
I have cleaned the mess and found that component Q5480 pins 3 and 4 (Picture 2, 3, 10 ) were burned out
Also R5488 and R5441 had pads missing ( Picture 2, 3, 10). Brought back the pads and found mosfet (Q5480) to buy so i replaced them.

As you can see in ( Picture 10 ) R5498 R3003 marked. They had each pad missing two which i have brought back too and replaced them.

So maybe you could help me from here cause im lost dont know which line to check is it ssd whats slow or cpu not getting right voltage. Or just vsense i dont know. Im just learning this so i tried my best explaining.

Would be nice if you could help me. 🙂
 

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2informaticos

Administrator
Staff member
First of all, welcome to the forum!

Post actual SMC_PBUS_VSENSE level.
Also run HWMonitor and post screenshot with reported values.
 

Ebix

New member
First of all, welcome to the forum!

Post actual SMC_PBUS_VSENSE level.
Also run HWMonitor and post screenshot with reported values.
Hello, thank you for reponse. SMC_PBUS_VSENSE at C5489 looks 0 on both ends on multimeter, when laptop is on. HWMonitor shows CPU core 8 at 129c so i guess thats were the problem is?
Also when replying could you explicitly explain what info you need cause i am koala its hard for me to understand.
Thank you!!
 

2informaticos

Administrator
Staff member
SMC_PBUS_VSENSE cannot be 0V.
Check resistors and traces around Q5480.
Post voltage on all of its pins.

BTW, do not quote an entire post, visible few centimeters above.
 

Ebix

New member
Plugged in with one port and motherboard

Q5480
Pin
1 - 0V
2 - 3.36V
3 - 0.011V
4 - 0V
5 - 0V
6 - 0V

i have replaced q5480 with mosfet i've bought because legs 3 and 4 were burned out on old one.
Also R3003 pin 1 has no connection to CB300/400 pin 1 in diode mode not sure if thats ok


clearly somethings wrong, adding pictures
Of current state and view.
 

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Last edited:

Ebix

New member
Thank you, that's helpful. But just for me not to fail on this part could you just tell me from what component pin to what component pin i just add wire to. As ppbus_g3h has loads of pins on board
 

2informaticos

Administrator
Staff member
"ppbus_g3h has loads of pins on board"
Just choose the easiest point to solder.
You should try to avoid long wire, closest bypass possible.
 

Ebix

New member
Ok so i just need to get ppbus_g3h wire to any of pins with pbus_s0_vsense_in on Q5480/R5441/R5481 any of them. If i understand correctly
 

Ebix

New member
I added ppbus_g3h wire now Q5480 measures :

1 - gnd
2 - 3.3v pulsing down to 0.7 and most of the time comes back to 3.3v
3 - 0V or tiny pulse of ~0.4v sometimes
4 - ~12v jumping down to 9/7V
5 - 12v jumping down to 7V
6 - 0V most of the time with tiny pulses to 1.17v

tested after wire assembled still same issues also including hwmonitor stats since i forgot last time.
 

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