User Guide

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5-1
5.Flow Chart of Troubleshooting and Circuit Diagram
5-1 SGH-A400 Power ON
N
‘POWER ON’ does not work
Y
Y
Check the current
consumption more than
100 mA
Download again
N
Y
Check the
Battery Voltage more
than 3.3V
Charge the Battery
N
Y
Check the pin
38 of U400 is more than
3.2 V
Check to the path from CN604 to pin
38 of U400 and keypad
N
Y
U400 pin 33,28,30
= 2.8V
Change U400
N
Y
END
Y
Check the clock signal
at R105
Check the clock generation circuit
(related to U400 and OSC100)
Check the initial operation