Sim Detect Troubleshooting - LG TU550 Service Manual

4. TROUBLE SHOOTING

4.10 SIM Detect Troubleshooting

USIM Initial sequence of TU550 is :
USIM_CLK,USIM_RST,USIM_DATA triggered → VREG_UIM_2.85V go to 3.0V → USIM IF work
Re-insert the SIM card
Work well?
VREG_UIM_2.85V is 3.0V?
USIM_P_CLK is run?
Change SIM card
Work well?
Change the Main board
LGE Internal Use Only
Start
Yes
No
NO
YES
Yes
No
USIM_P_DATA
USIM_P_CLK
End
Check CON500
End
USIM_P_RST_N
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Ground
VREG_UIM_2.85
Only for training and service purposes