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4. TROUBLE SHOOTING
LGE Internal Use Only
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4.8 Power ON Troubleshooting
Power On sequence of U370 is :
PWR key press
→
PM_ON_SW_N go to low, PM6650 KPDPWR_N (pin24)
→
PM6650 Power Up
→
VREG_MSMC_1.2V, VREG_MSME_1.8V, VREG_MSMP_2.7V, VREG_MSMA_2.6V,
VREG_TCXO_2.85V power up and system reset assert to MSM6245
→
Phone booting and
PS_HOLD assert to PMIC
Start
Battery Voltage is higher
than 3.2 V ?
YES
NO
Insert Well Charged Battery
or Charging the Battery
Change the Main board
Press PWR_ON key ?
YES
Check Belows,
MSMC_1.2V , MSMP_2.7V
MSME_1.8V , MEMA_2.6V
VREG_TCXO_2.85V
YES
Check TCXO / Sleep Clock
R306 : TCXO_MSM ( 19.2 Mhz)
TP311 : ( 32.768 Khz)
YES
NO
Check the Key Dome
NO
Try to replace PM6650 ( Level 3)
or , Change the Main Board
NO
Check the TCXO
and PM6650
Summary of Contents for U370
Page 1: ...Date January 2008 Issue 1 0 Service Manual Model U370 Service Manual U370 ...
Page 178: ...Note ...
Page 179: ...Note ...