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5. Flow Chart of Troubleshooting and Circuit Diagrams
5-1 Power ON
SGH-N500 Flow Chart of Troubleshooting and Circuit Diagrams
5-1
'POWER ON'does not work
Charge the Battery
Check the Battery Voltage
is more than 3.2V
No
Yes
Yes
Replace Keypad
When the "END" key is
pressed, the voltage of "D304 pin1"
3.6V?
No
Yes
U474 pin 2,3 > 3.2V
Check the circuit related to U474
No
END
U623 pin5 3.0 V ?
Check the circuit related to U623
No
Yes
Check the initial operation
U622 pin5 3.0 V ?
Check U622 and related circuit
No
Yes
Check for the clock signal at R107
Check the clock generation circuit
(related to U100 and Q100)
No
Yes
Yes