Nokia 3806 Service Manual page 111

RM-583
Baseband Description and Troubleshooting
VBAT, VPH_PWR, VREG_S1, VREG_S2, VREG_MPLL, VREG_MSME1, VREG_MSME2,
VREG_MSMA, VREG_RUIM, VREG_USB, VREG_XO
2. If the voltages are abnormal, check the fault reason.
Case Two:
If current is zero, check CN1 and C1017,C1018,D1050,D1051,Q1001,U1.If there is no power output, U1
is defective. Module cannot be repaired and must be replaced.
Case Three:
1. Raise the voltage of PS-HOLD and measure each output voltage of PMU, such as: VREG_S1,
VREG_S2, VREG_MPLL, VREG_MSME1, VREG_MSME2, VREG_MSMA, VREG_RUIM,
VREG_USB, VREG_XO;
2. Check if the clock (19.2MHz）and RTC（32.768KHz）are normal.
3. If the signals are abnormal, check the fault reason;
4. If they are normal, check the welding of QSC and Flash, perform welding or replacement.
(Replacement includes Flash Updating).The welding of the display panel connector should also be
checked, for the potential short of the parallel data signal and Read & Write signal on the display
panel connector will lead to the failure of QSC in invoking the programs of FLASH.
Case four:
This case is caused by no program in Memory. For details please refer to below flow chart.
Issue 1
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