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| MacBook Air A1932 Not turning on, pulling very low current at 5V or 20V repair | |
|---|---|
| Device | MacBook Air A1932 |
| Affects part(s) | Motherboard |
| Needs equipment | multimeter, soldering iron, soldering station, thermal camera |
| Difficulty | ◉◉◉◌ Hard |
| Type | Soldering |
Problem description
Diagnosing and resolving issues where a MacBook (820-01521) is pulling very little current at either 5V or 20V as indicated by a USB-C current meter with SLPS2R and AWAKE voltages/signals cycling.
Symptoms
- MacBook not turning on
- Very low current draw at either 5V or 20V
- SLPS2R and AWAKE voltages/signals cycling
Solution
Diagnostic Steps
Check voltage and resistance to ground on
PP5v_G3S
The resistance to ground on PP5v_G3S should fairly high, well within the kilo-ohms. Voltage should be around 5v. Values less than 4.9v should be considered abnormal.
PP3v3_G3S
The resistance to ground on PP3v3_G3S should fairly high, well within the kilo-ohms. Voltage should be around 3.3v. Values less than 3.215 should be considered abnormal.
PP1v8_G3S
The resistance to ground on PP1v8_G3S should fairly high, well within the kilo-ohms. Voltage should be around 1.8v. Values less than 1.70v should be considered abnormal.
PP3v_G3H
The resistance to ground on PP3v_G3H should fairly high, well within the kilo-ohms. Voltage should be around 3.0v. Values less than 2.915 should be considered abnormal.
Repair Steps
If no shorts were found on the listed rails above, replace U7800.
If you found a short on the listed rails above, inject 1v into the rail and perform thermal imaging. Replace the shorted component.