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Flow Chart of Troubleshooting
7-20
7-11. Key Back Light
U716 pin 1 = H ?
Check the U716 related to "KEYLED_ON"
signal
END
No
Yes
Yes
Main Key LED does not work
U716 pin 4 = H ?
No
Replace U716
Yes
typical 3.8V
6
5
SEL
STBY
1
3 VIN
4
VOUT
VBAT
U716
GND
2
GND
C754
C753
+VDD_BL
KEYLED_ON