820-01521 water damaged does not start

Hi everyone

water damage at the following locations:
connector J3300 and its surroundings
R2890, R3098, U2890 visible signs of overheating on the cover

after connecting the meter to USB C 5.1V 0,3A,
damaged part U3100 (CD3215A10 it has such a designation in the diagram, CD3215C00Z such a marking was on the damaged element, CD3215B01 such a marking is on the element that I soldered) This change does not have a negative effect on performance ?
after replacing the heating element(U3100), it looks like a hare 5,1V 0,24A

diode test with a red court on ground
F3000 0,132/ 0,718 kΩ
F3010 0,132/ 0,721 kΩ

what should i check next ?


Staff member
Replace CD3215C00 with CD3215C00, not B01...

You should be sure about traces, solders and U2890 surrounding components.
Did you note any liquid sign at audio board, or connector?
Last edited:
CD3215C00 It is ordered but it will take a month. It will reach me

all connections have been improved around U2890

the audio board was also gently flooded around the connector :-(

the next step is ...
visibility signs of corrosion are around PPBUS_G3H, GND connectors 35 /49
50% chance that T2 survived

before soldering new ones CD3215C00 what should i check ?
PP3V3_G3H present (2,28 V )


Staff member
"PP3V3_G3H present (2,28 V )"
You can say present "somehow", but incorrect voltage.

Could be waste of time, trying to fix USB-C area and find bad T2 at the end.
Liquid damage on these small, high density boards, is almost letal.
I wish you would understand me thoroughly.
I am not a service. I bought this Macbook with a desire to repair and learn something new.

I have no experience repairing apple products. I do repairs of electronic equipment as a hobby because I like to do it (my job is a mechanic).
If he writes some crap like before, please correct me.


Staff member
Is not the best option with such board.
However you can continue, only understand this could be nightmare project.

Which is the actual PPBUS_G3H voltage?
I realize that the next money thrown away.

CD3215C00 both pieces have been desoldered and are waiting for the shipment with new ones. When they are not on the board, after connecting USBC, nothing happens, the charger does not start (I assume that it is normal?)


Staff member
USB-C power delivery protocol is a bit complicated.
Normal charger (not fake one) doesn't deliver any voltage on the VBUS.
There is a hardware detection through CC1/2 pins, to enable 5V first.
After that, serial communicatioen (1-wire over CC1/2) is required, to switch to nominal voltage needed by the device.
As CC1/2 pins are controlled by CD3215 chips, you cannot expect any voltage, w/o them on the board...
that's why the whole project has been packed and waiting for components
If I don't really fix this motherboard, I will have to buy a working one.

connector J3300 20875-056E-01 where to look for such things, google shows everything but not what I'm looking for


Staff member
At J3300 you can check diode mode to ground at VBUS and CC1/2 lines.
Once CD3215 chips soldered back, check again and be sure no short anywhere.
After re-soldering the CD3215 chips
still only 5V power supply




P3V3G3H_PHASE 0,460 --3,29/3,3V
PPBUS_G3H 0,471 -- 12,29V should 13,1V ?

what to diagnose next ?
this was done with a regular usb cable and a 2015 macbook. I do not hide that the video of Luis helped, with a laptop with a sticker "dont tuch KURWA" (my compatriot I'm also from Poland).
So the macbook starts, it gives a sound, it highlights the keyboard, but there is no image backlight (if you use a flashlight, you will see the login window)
So the project is not finished yet.

What measurements should MY TEACHER take for you?