820-00840 Stuck at 5V

[KootenayMacGuy]

Hi there. This Macbook came in with no power. Stuck at 5V on both USB-C ports and hovers between 40mA and 26mA, never gets to 20V. . I believe it was a cheap power cable that caused this.

Board is 820-00840. PPBUS_G3H is missing, all other necessary voltages appear to be present. There are no shorts on any main power lines.

I have replaced:

Both CD3215's
Both Q3100 & Q3200
U8210
U7000 (twice)

Checked all resistors around U7000 and all seem within spec.

Please help.

 

[2informaticos]

Inspect USB-C redriver chip for damage; does it get hot?

Post PPBUS_G3H and 3V3_G3H voltage; diode mode to ground, if no voltage.

 

[KootenayMacGuy]

No heat on redriver chip.

PPBUS_G3H is 0.061V
PP3V3_G3H is 3.402V

 

[KootenayMacGuy]

PPBUS_G3H diode reading is 0.438

Replaced the redriver chip anyway and no change.

 

[2informaticos]

Check SMC_USBC_INT_L level.
Post U7000 basic voltages; P_IN, AUX_DET, SMC_RST_IN, VDDA/P, SMC_RST*, AUX_OK, A/B_MON.

Remove F7000 and check C7050 voltage.

Did you test with good battery (holding some charge)?

 

[KootenayMacGuy]

SMC_USBC_INT_L = 3.401
P_IN = 5.194
AUX_DET = 1.290
SMC_RST_IN = 0V
VDDA = 5.109
VDDP = 5.109
SMC_RST_R_L = 3.410
AUX_OK = 3.410
A_MON = 0V
B_MON = 0V

Attempting to connect a known good battery causes there to be no activity on charger. Tried two different batteries. As soon as battery is disconnected, charger turns on to 5V 0A

 

[KootenayMacGuy]

I removed U7000 and C7050 voltage is 0v

 

[2informaticos]

What voltages do you get on the board when battery is connected?
Any reaction if you trigger SMC_ONOFF_L?