Sim Detect Troubleshooting - LG CU405 Service Manual

4.9 SIM Detect Troubleshooting

USIM Initial sequence of CU405 is :
USIM_CLK,USIM_RST,USIM_DATA triggered → VREG_UIM_2.85V go to 2.8V → USIM IF work
Start
Re-insert the SIM card
Work well?
VREG_UIM_2.85V is 2.85V?
USIM_P_CLK is run?
Change SIM card
Work well?
Change the Main board
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Only for training and service purposes
Yes
No
NO
Check J500
YES
Yes
No
USIM_P_DAT A
USIM_P_CLK
USIM_P_RST_N
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4. TROUBLE SHOOTING
End
End
VREG_UIM_2.85
Ground
LGE Internal Use Only