| MacBook Pro A1990 Not turning on, drawing 0.00A - 0.02A at 20V repair | |
|---|---|
| Device | MacBook Pro A1990 |
| Affects part(s) | T2 firmware |
| Needs equipment | None |
| Difficulty | ◉◌◌◌ Easy |
| Type | Software |
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Problem description
A1990 MacBook not turning on, drawing 0.00A - 0.02A at 20V, PP3V3_G3H_SOCPMU present, but PPVCCPRIMCORE_PRIM_REG and therefore PP3V3_S5 missing.
Symptoms
- Not powering on
- Missing PP3V3_S5 and PPVCCPRIMCORE_PRIM_REG voltages
- Only drawing 0.00A - 0.02A at 20V as measured by USB-C meter
Solution
Do not replace U7800. Instead, put device into DFU mode and select advanced -> repair. Read this apple article.
The problem seems to be T2 not talking to the PMU correctly. Note, you need a battery connected for PMU to work. Best to completely assemble the device.
The 2019 16" model has the same issue.