820-02020 A2338 - 20V on USB but no charging

[techmagnet]

Hi there,

I have a m1 2020 (battery was completely flat, would not power on)which gets 20V over USB Charger but with almost 0A draw (0.04A) with battery removed board only. Sometimes goes a bit up.

I moved the board to a working case and it powers on loads accounts etc but doesnt charge battery. So the logic board itself seems fine, however there is a problem with USB / Charging.

so summarized: Board works in a different case with a charged battery. Battery in the original case is flat (wont power on in there, because probably didnt charge anymore) Powered on in the other case i got 20V 0,1A draw but no charging.

how can i further troubleshoot ? I ordered the cd3217b12 chips, but as i get 20V shouldnt that mean they are probably fine ? What should i measure and continue to troubleshoot. Boardview and shematics i have.

Thank you!

 

[2informaticos]

First of all, welcome to the forum!

Please, confirm what MLB you have; 820-00281 is A1707 (2016), not M1 (2020) machine.
Do not tocuh USB-C are yet.

 

[techmagnet]

copy paste mistake ofc 820-02020 (A2338)

 

[2informaticos]

If USB-C input switch to 20V without battery, the probleem should not be on USB-C area.
First, check the level for SYS_DETECT and SYS_DETECT_L signals.
You can force the detection joining R5155 pads.

Also check voltage and diode mode on SCL/SDA lines of battery bus; before, and after UD200/1.

 

[techmagnet]

Measures without battery connected

SYS_DETECT 3,8V
SYS_DETECT_L 0V

1.8V SDA on RD203 left side
1.8V SCL on RD202 left side

around 1.3V SDA on RD201 bottom side
around 1.3V SCL on RD200 top side

 

[2informaticos]

You sould check all SCL/SDA lines of UD200/1; in diode mode also.

With the good battery, this board shows its percentage correctly?

 

[techmagnet]

Measures without battery connected

Voltage:

SYS_DETECT 3,8V
SYS_DETECT_L 0V

1.8V SDA on RD203 left side
1.8V SCL on RD202 left side

around 1.3V SDA on RD201 bottom side
around 1.3V SCL on RD200 top side

3.3V SDA on RD208
3.3 SCL on RD207

Diode Mode:

SDA on RD203 = 1.89
CDL on RD202 =1.89

SDA on RD201 = 1.7
SDA on RD200 =1.7

SDA on RD208 = 1.77
SCL on RD207 = 1.77

I just got myself a new battery to test the board. It boots up fine, battery indicator STUCK shows all the time 32%... Amp draw 0,1A at 20V.. no charging

 

[2informaticos]

Remember to check diode mode with red probe on ground; black probe on test point.

 

[techmagnet]

oops sorry:

SDA on RD203 = 0.522
CDL on RD202 = 0.530

SDA on RD201 = 0.308
SDA on RD200 = 0.308

SDA on RD208 = 0.473
SCL on RD207 = 0.476

 

[2informaticos]

One of UD200/1 may be bad.
You can also try DFU mode, just in case.

 

[techmagnet]

Thanks!

2 questions, and sorry about that I’m quite new to macbook repairs. Usually I do consoles and stuff.

1) is there a source to source UD200 / 1 ? I don’t have a donor as Im not a repair shop. Soldering is no problem.

2) DFU I tried, I have another working m1 I repaired and I put the broken one in dfu mode, in Apple Configurator I chose „repair“ , but at some point on installing system it always reboots and doesn’t finish dfu restore… not sure if I chose the right option.

Thank you very much!

 

[2informaticos]

You can try revive in DFU.
But, if no data to save, go for restore.