A2289 820-01987 Battery issues - Switches off on battery, works on a charger after liquid around battery comm line

[it-solve]

Strange case, had a small amount of liquid around the ribbon comm line cable from the battery.
Cleaned the socket and ribbon cable. Batt is not charging, sometimes pulls up to 0.9A and then drops back to 0.2A

Replaced the battery with spare I had from another A2289 (not new ordered) Exact same behaviour.
System shows replacement needed for both batteries. Tried SMC reset and can't get batter data anymore in iStats

U7000 lines shows Diode mode of about 0.5-0.7VDc, no shorts.

Wiped and reinstalled the system as system was corrupted.

I can see a pulse on the SMBUS batt line with bare board and battery

PPVBAT_G3H_CONN - 12.67V
SMBUS_3V3_BATT_SDA - ~2.4V
SMBUS_3V3_BATT_SCL - ~1.7V
SYS_DETECT_L - 0V

 

[2informaticos]

"SMBUS_3V3_BATT_SDA - ~2.4V
SMBUS_3V3_BATT_SCL - ~1.7V"
Don't look good; what about diode mode?
Check in ohm scale also, both probe ways.
D6950 may be bad.

BTW, forget about VDc for diode mode readings.
Don't create confusion with voltage mode.

 

[it-solve]

SMBUS_3V3_BATT_SDA - 0.98 / 0.6MOhm
SMBUS_3V3_BATT_SCL - 0.96 / 0.7MOhm

D6950
Looks ok to ground, shall I replace it?

Yeah the diode mode is confusing. Ive seen it marked as 700 for 0.7, so report as digits only?

 

[2informaticos]

The voltage measured in diode mode is generated by the constant current injected by multimeter.
So is not a "real" voltage, which we search with power connected.

You can remove D6950 for test.

What readings do you get on the other side of Q6950?

 

[it-solve]

I2C_PWR_SDA_R1 - 1.80V pulsing
I2C_PWR_SCL_R1 - 1.80V pulsing
PP1V8_SLPS2R - 1.80V


This with removed D6950 . Charger and batt bare board

20V 0A-0.4A

Assembled and did SMC reset again; battery not detected. Although shows 0 cycles in system report. Must be a comm issue with the battery.

 

[2informaticos]

Be sure R6951/2 have the same ohm value.
Replace Q6950, just in case.
Yu can nalso test shorting R6955 pads.

 

[it-solve]

R6951/2 quite close values within 4.7K range
R6955 pads no short in MOhm range


Replaced Q6950, same effect 20V 0.7A->0.1A->0.7A...

If battery is empty doesn't even turn on.

 

[2informaticos]

I said to make short over R6955 pads.
Just to be sure about SYS_DETECT_L signal low.

If doesn't turn on without battery, what is USB-C power behavior?

 

[it-solve]

My apologies must have misread that line.
Installed a push switch and board back in case. Pressed when attached adapter. I am getting 20V 1A -> 0.5 -> 0.2 -> 0.8 -> 0.2 keeps cycling but never goes above 0.8

With battery and screen when not charging 20V 0.3A-0.5A and loading OS as expected (this both with SYS_DETECT_L low /high)
Battery information: Capacity 0 / Cycle Count 0 only. No other information.

Only bare board on the desk 20V - 0A->0.10A->0A stabilisied. Hard to say if running or not. Maybe just not initiating the CPU when nothing is connected, that heat blob seems like T2

 

[2informaticos]

Let R6955 pads shorted.

 

[it-solve]

yes that what I did. Keeping them shorted through the whole process. of starting up. Current consumption hasn't changed.