820-00923-A No left side USB activity

[powerblackout]

Board couldn't boot due to corrosion under UB090, stuck at 5v 20-30mah. After cleaning that up the board boots and charges, 20V on all 4 TB ports.

Trackpad and keyboard currently don't work due to a failed battery swap that left gouges in the trackpad board exposing traces. Touch bar doesn't work either, haven't started troubleshooting that.

USB devices aren't detected on the JB500 connector. any orientation, either of the ports. Tried known working flex connector. When using an ammeter I see no power flowing out to the USB device, when connected to J3300 5V 200mah goes out to the device and operates normally. Tried reflowing UB000 since it's so close to the UB090 maybe corrosion got underneath also, but still have same issue.

I've checked the power going into the chip, all are present:
PP0V9_TBT_T_DP
PP0V9_TBT_T_PCIE
PP0V9_TBT_T_USB
PP0V9_TBT_T_CIO
PP3V3_TBT_T_ANA_PCIE
PP3V3_TBT_T_ANA_USB2
PP3V3_TBT_T_LC
PP3V3_S5_TBT_T_SW
PP3V3_TBT_T_F
PP3V3_TBT_T_S0
PP0V9_TBT_T_SVR
VR0V9_IND_TBT_T
PP0V9_TBT_T_LVR
TBT_T_USB_PWR_EN
TBT_T_PCI_RESET_L
USBC_T_RESET_L

I don't believe it's any of the diodes since both of the ports on one side have the same issue.

How do I troubleshoot the USB controller to see if it needs to be replaced?

[powerblackout]

Re: 820-00923-A No left side USB activity

Finally got the password and was able to reset machine back to factory. after SMC reset the touch bar started working again.

When looking in the system information panel for USB it only lists one of the hubs. Any ideas?

[mon2]

Re: 820-00923-A No left side USB activity

Remove all power. Meter in DIODE mode.

Red meter probe, yes RED to ground.
Black meter probe to point to test.

Test the diode mode of the D+ pin.

Repeat for the D- pin. Note each measurement.

Compare the diode mode readings of a working port.

Post each measurement.

[powerblackout]

Re: 820-00923-A No left side USB activity

the readings from both sides of the board (2 working right side 2 non working left side) all match.

D+/- are 0L on all four ports (including the ones that work)

Everything else is 0L except for these:

VBUS 0.173
CC1 0.593
CC2 0,593
RX2- 0.350
RX2+0.350
RX1- 0.350
RX1+ 0.350

[powerblackout]

Re: 820-00923-A No left side USB activity

After looking at the schematic more I found the line that turns on the 5V when a usb device is plugged in, UPC_T_5V_EN which has a 0.5ohm short to ground. Checked UPC_X_5V_EN which has 11K resistance.

EDIT: removed UB700 and the 0.5ohm short remains, meaning UB300 or UB400. Inject voltage to figure out which CD3215 has the short? 1V do the trick?

[mon2]

Re: 820-00923-A No left side USB activity

If you had 20v on each port, then these ACE controllers are (were) working fine.

At this stage, yes, you can try 1 volt (not higher to be safe) voltage injection @ 2A+. Check the current consumption of the DC power supply you are using for this injection. Monitor which part heats up with thermal camera or IPA (Costco stuff works great).

[powerblackout]

Re: 820-00923-A No left side USB activity

I reballed UB300 and UB400 and now 5V is being generated and USB devices work on both sides now!

I think this would be worth adding to the repair wiki? even if UB300/400 can get up to 20V, boot, and charge battery, there could still be something shorting the 5V enable line coming from UB300/400 going to UB700?

Thank you for your help mon2!

[mon2]

Re: 820-00923-A No left side USB activity

Well done!! Yes, absolutely, update repair wiki with your details.