820-01949 Wont charge battery

[No-Clean]

Clean board, battery is recognized in OS, stays at 1% and OS said battery is not charging, runs from battery only.

Tried different known good battery and flex and same thing.

Tried different charger same thing.

SYS_DETECT_L 0V
SYS_DETECT 3.3V

Diode readings on J6951 are fine.

Board alone gets 20V no problem.

 

[2informaticos]

Save data and try DFU restore.

 

[No-Clean]

Restored T2 no data and installed clean OS, same problem still.

 

[2informaticos]

Are you sure battery screw is tighten enough?
I got the same behavior 2 days ago; forgot to tight the screw...

 

[No-Clean]

Yes, tried 2 different batteries and 2 different screws, both tight and after connecting battery, flex and charger board boots, no charger I get around 11V on main so the battery is for sure well connected.

Also replaced U7000 but same result.

 

[2informaticos]

Check A/BMON levels; w/ and w/o battery connected.
Also check resistance (ohm scale) over C7020/23.

 

[No-Clean]

C7020 ohm AB 150k or end to end 4ohms
C7023 ohm AB 60k or end to end 4ohms

A/BMON 0V with battery connected, with and without charger
A/BMON 0V without battery connected, with charger connected

 

[2informaticos]

Check voltage and diode mode at I2C_PWR_SCL/SDA lines.

 

[No-Clean]

No battery, just power supply:

Diode 470 both
Voltage mostly 2.6V then changes back to 1.8V and repeats both of them

With battery voltage is about the same behavior.

 

[2informaticos]

Try changing Q6950.

 

[No-Clean]

Still the same

 

[2informaticos]

Check battery data flex markings on its bottom side.
Be sure to connect each end on its correct side.

 

[No-Clean]

Just did, but same thing, Mac runs off from battery if there is charge, I do get percentage at the top right inside OS charger is detected and shows the sign of charging but it saids Mac is not charging even after a while.

 

[2informaticos]

NLBA1 is able to properly check the battery.
If you don't have it, can you try this battery on other compatible Mac?

 

[No-Clean]

Thanks, I tried another original battery from another case and same thing.

 

[2informaticos]

When it runs from battery, percentage drops correctly?
What is PPBUS_G3H voltage with charger alone?
Also check USB-C ports behavior without battery.

 

[No-Clean]

Yes percentage drops normal.

Charger alone no battery connected 12.3V

All 4 ports make it to 20V with no restarts

 

[No-Clean]

Im about to return this to the customer, any other tips I should try, this seems really weird to me, the battery is not the problem.

 

[2informaticos]

There is a problem with PPBUS_G3H control; it should stay at 12.6V without battery.
U7000, U7800 and T2 are all involved in the control.
If voltage and diode mode readings on SCL/SDA lines (in front and back of Q6950) are good, then no more ideas...

 

[No-Clean]

Tried new U7000 and U7800 and same result, thanks for your time and help