Apple M4753 manual

		Troubleshooting		Symptom Charts/Power - 8
			1	Try known-good, charged battery.
	Premature low-
power warning			2	Try known-good power adapter.
appears			3	Replace sound card.
			4	Replace PMU board
			5	Replace PMU cable.
			6	Replace power supply card.
			7	Replace I/O logic board.