macbook a1707 820-00928

[PITERPENY]

the board is not filled! 3 ports consume 5v/0.265a and overload! one port 20v/0.120a and reboot and so constantly overload! no short circuits! replacing the U7000 did not help! replacing the BIOS also did not change anything! tell me what else can be checked! so far my suspicions are on the U1100

[PITERPENY]

PPBUS_G3H=1.7V
PP1V1_UPC =0 all cd3215

[mon2]

Remove all power. Flux and remove the fuse on PPBUS_G3H. Meter in resistance mode. Measure the resistance to ground of the 2 pcb pads where the removed fuse was soldered. Post the measurements.

[piernov]

Of course the USB-C controller for the port that acts differently is gonna be bad.

[PITERPENY]

Of course the USB-C controller for the port that acts differently is gonna be bad.

I thought so too and replaced all four CDs but the behavior remained the same! The problem is not in the CD!

[PITERPENY]

Remove all power. Flux and remove the fuse on PPBUS_G3H. Meter in resistance mode. Measure the resistance to ground of the 2 pcb pads where the removed fuse was soldered. Post the measurements.

with f7000 PPBUS_G3H=6.9 kOhm (diode 0.400)!
with f7000 removed: PPBUS_G3H=6.9 kOhm (diode 0.390)
PPVBAT_G3H_CHGR_REG=13.2 kOhm (diode 0.520)

when f7000 is removed, usb ports also reboot cyclically

[mon2]

Measure the resistance to ground of each of the USB port's VBUS line. Perhaps a local USB load switch is defective.

[PITERPENY]

I have PPBUS_G3H=1.7 V and it should be 13 V! Who forms this voltage? VBUS = 5 V (d0.122) 0.700 kOhm

[mon2]

U7000 = ISL9239 is the buck / boost regulator that creates PPBUS_G3H.

If the input voltage is 5v on VBUS, then this regulator will enter BOOST mode to booth the output to a required voltage. Whenever the voltage is boosted, the current support is for low loads.

After the PD controllers negotiate 20v from the power adapter then the VBUS = 20v and this U7000 regulator will enter buck mode to lower the 20v down to the required voltage.

If the PPBUS_G3H voltage is low, inspect this area and without power to the board, confirm the resistance of the dual mosfets @ Q7030 and also Q7040.

Measure the full resistance path of the VBUS input resistors by probing across C7023. Does this resistance match the schematic values? Should be ~2 ohms.

[PITERPENY]

I put the board in another case with a charged battery and all 4 USB ports show 20V/0.250A (stable). But it doesn't charge and the fans work at high speed despite the touchpad being connected! The system doesn't boot! C7023=2.7ohm

[mon2]

Try a DFU. Double-check your interconnect cables from the trackpad assembly.

Is the trackpad & trackpad cable a known good pair?

[PITERPENY]

dfu A1707 is not supported! The case with a fully working MacBook and another board works fully in this case! The problem is on the board! It does not see the battery apparently and therefore does not charge! The problem is in the power supply network, but I do not understand where! Maybe the problem is in the Thunderbolt firmware?