TroubleshootingSymptom Charts/Power - 4

Power

Computer won’t

1

If sleep LED is continually on, backup battery power has been

power up

 

interrupted. Restart computer by holding down Shift-FN-

 

 

Control and power on key. Wait 5 seconds and press power on

 

2

key. If computer doesn’t restart, repeat 3–4 times.

 

Try known-good power adapter.

 

3

Try known-good, firmly seated, charged battery. Repeat once.

 

4

Connect power adapter and restart computer in 3–4 minutes.

 

5

Verify PMU cable is fully seated on I/O logic board.

 

6

Disconnect internal keyboard and try powering up unit. If unit

 

7

powers up, replace keyboard.

 

Verify that microprocessor card is seated firmly in connector.

 

8

Replace sound card.

 

9

Replace power supply card.

 

10

Replace PMU card.

 

11

Replace I/O logic board.

 

12

Replace microprocessor board.

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Apple M4753 manual Power