820-00840 Power loops when it climbs to 20V

[No-Clean]

Clean board, all ports on both sides reboot when the voltage tries to get up to 20V, U7000 had a tiny amount of corrosion on pin 36 TBA_GATE_Q1 but it was not shorted.

I checked for shorts on all rails found nothing bad.

LDO on CD3215 are all measuring fine.

Components already replaced both CD3215, U7000, U2800 and another component that often fails but it is not on the schematic I have, it is located next to the USB ports.

 

[2informaticos]

Check what happens if you connect known good charged battery.

 

[No-Clean]

With charged battery it turns on keeps 20V but 0A and wont charge.

 

[2informaticos]

Check if board starts with battery.
What you get then on PPBUS_G3H and 3V3_G3H?

 

[No-Clean]

Board starts and loads system with charged battery.

PPBUS_G3H = 11V

3V3_G3H = 3.3V

 

[2informaticos]

What is PPBUS_G3H with charger alone (no battery)?
If not present, check SMC_USBC_INT_L.

 

[No-Clean]

PPBUS_G3H with charger alone (no battery) 4.5V

 

[2informaticos]

Really strange, possibly bad Q7030/40.
Post U7000 basic voltages (charger alone); P_IN, AUX_DET, VDDA/P, AUX_OK, A/BMON.

 

[No-Clean]

Thanks, as soon as you mentioned Q7030 I remembered that pin 36 TBA_GATE_Q1 goes directly to it and that was the pin that had corrosion on U7000 so I just replaced Q7030 and board works.