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Flow Chart of Troubleshooting
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9-17
9-9. Key Back Light
Main Key LED does not work
Yes
No
Resolder doesn't work LED
check LED400,401,403,404
does work or not.
Yes
Resolder C304
or
Replace U313
or
Change PBA
VDD_KEY_3.3 = 3.3V
END
Yes
No