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Only for training and service purposes
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4. TROUBLE SHOOTING
Battery voltage. higher
than 3.20V?
VA106 go to low
when key press?
NO
YES
YES
YES
YES
NO
NO
NO
4.7. Base band part
4.7.1 Power ON Troubleshooting
Power On sequence is :
PWR key press
Æ
KPDPWR_N (QSC6240 KPDPWR_N pin(AA10)) go to low(VA106)
Æ
QSC6240 Power Up
Æ
VREG_MSMC_1.2V(C203), VREG_RF1(C217), VREG_MSME_1.8V(C237), VREG_MSMP_2.6V(C229),
VREG_RF2_1.4V(C259), VREG_MPLL_1.3V(C240), VREG_USB2P6(C227), VREG_TCXO_2.85V(C239) power up and
system reset assert to MSM
Æ
Phone booting and PS_HOLD assert to PMIC
Start
Change the main board
VREG_MSMC_1.2V
VREG_RF1_2.3V
VREG_MSME_1.8V
VREG_MSMP_2.6V
VREG_RF2_1.4V
VREG_MPLL_1.3V
VREG_USB2P6
VREG_TCXO_2.85V
power up?
Is clock ok?
X201 : 32.768KHz
C108 : 19M
Change or charging the Battery
Check the Key Dome
Change the main board
Check the TCXO & Sleep Cystal