MacBook Pro A1708 Charger stuck at 5V instead of 20V repair

Problem description
Charging voltage from USB-C charger is stuck at 5V instead of 20V.

For more information about this problem, check Charger stuck at 5V instead of 20V on MacBooks

Symptoms

 * Not charging
 * Most likely not turning on
 * Drawing very little current

Solution

 * If 5 V and 0.00 A draw, most likely a 0–1 Ω short to ground on PP3V3_G3H
 * PP3V3_G3H missing due to a short circuit on the input to PP3V3_G3H creation circuit

Example video (board taking 35 mA, 160 Ω short on PPVIN_G3H_P3V3G3H (input PP3V3_G3H creation circuit), fixed by replacing 3 capacitors and 1 diode)


 * 5 V varying slightly around 0.05 A, repaired by reflowing with hot air and flux U2800 (TBT ALPINE RIDGE chip) and components around through the aluminium enclosure
 * Corroded LDO capacitor for PP3V3_G3H around a CD3215
 * PP3V3_G3H missing due to PM_EN_P3V3_G3H missing due to bad ISL9239

Example video (device not turning on, charger taking 0 mA)


 * Bad CD3215
 * Bad CD3215 ROM chip (U2890)
 * Bad solder of R3000 or R3001 resistor (not passing PP3V3_G3H through to one of the CD3215s)
 * Bad / dead ISL9239 — it needs to make the enable for the 3.3 V regulator (U6990), PM_EN_P3V3_G3H
 * Bad / dead SMC — it needs to talk to the CD3215s to tell them to go to 20 V
 * Bad pi3usb32 (USB switch, not present on boardview, located next to usb ports)

Example video (PP3V3_G3H 0.3 V, resistance to ground measured as 380 kΩ, active short caused by pi3usb32, found by using thermal camera)