Flow Chart of Troubleshooting and Circuit Diagrams
5-7
5-4 Sim Part
Q402 pin5 = "H" ?
Replace Q402 or
Replace PBA
END
Yes
No
Check the circuit around U617
(Serial EEPROM) and data stored in it
Yes
Phone can't access SIM card
Yes
Q402 pin 2, 3 = 3.0 V ?
Replace Q402 or
Resolder C434
Yes
No
After Power ON,
Check SIMCLK Signal on J402 pin 3
in a few second
After SIM card insert,
J402 pin 2 = "H(SIMRST) ?
Resoldering C718 or
Replace PBA
Replace PBA
Yes
No
No
Q402 pin4 = 3.0 V ?
Yes
No
Check the circuit around U620