Chart Of Troubleshooting; Baseband; Power On - Samsung SGH-C250 Service Manual

3. Flow Chart of Troubleshooting

3-1.Baseband

3-1-1. Power ON

'Power On' does not work
Check the current consumption
Current consumption
>= 100mA
Check the Vbat Voltage
Voltage >=3.3V
Check the pin of UCP101
Pin#J12 >= 2.8V
Pin#A13 and
pin#A14 =2.8V
Yes
Check the clock signal at pin#21 of U300
Freq = 26MHz
Vpp >=400mV
Vpp ≒ 600mV
Check the clock signal at pin#5,#6 of U303
Freq = 13MHz
Yes
Check the initial operation
END
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③
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⑤
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Charge the Battery
①
Check UCP101 and C116
No
pin#G11 =
1.8V
Yes
Check the clock generation circuit
(related to OSC300)
⑥
Check U303
3-1
②
Check UCP101 and C117
④