View source for MacBook Pro A2338 Not turning on, 0.20-0.25a current draw at 5V with power cycling of the USB-C amp meter repair

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== Problem description ==
No Power on, 5v and ~0.20-0.25a as measured on the USB-C amp meter, with power cycling of the USB-C amp meter on the 820-02016 logic board.

== Symptoms ==
* 5v / ~0.20-0.25a with power cycling of the USB-C amp meter.
* All voltages missing

== Solution ==
=== Diagnostic Steps ===
[[File:Placeholder image.jpg|thumb|(Figure 1) -- No image yet. Help expand this page by uploading it!]]
High-resolution thermal imaging is the preferred first-line diagnostic method on M1-based boards when a short to ground on an S2 rail is suspected. Voltage injection is usually not required. If high-resolution thermal imaging is unavailable, proceed to the steps below to identify a short on PP3v3_S2 or PP1v25_S2.

====Measure diode mode readings to ground on PP3v3_S2====
*LC710 is the best place to measure for a short on PP3v3_S2 on the 820-02020 logic board.
*#Place your multimeter in diode mode, and place the red probe on a grounding point such as a screw hole and the black probe on LC710.
*#Normal diode mode reading to ground on PP3v3_S2 is around .440.

====Measure diode mode readings to ground on PP1v25_S2====
*Pin 2 of L77D0 is a good place to measure from.
*#Normal diode mode reading to ground on PP1v25_S2 is ~0.490.

Shorts to ground are generally considered when the diode mode to ground reading is significantly less than the above normal values. Readings can vary due to temperature or normal wear.

[[How to find short circuits]] If a short to ground is measured, inject voltage to the associated line. Generally, 1v at 3-5 amps is sufficient to find most short circuits. NEVER INJECT MORE VOLTAGE THAN THE LINE IS RATED FOR! Carefully feel around the board for a warm area or utilize thermal imaging, then localize the shorted component using isopropyl alcohol. The alcohol will rapidly evaporate off the shorted component.
=== Repair Steps ===

====Short to ground on PP1v25_S2 or PP3v3_S2====

*Replace the shorted component.