LG HB620 Service Manual

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4. TROUBLE SHOOTING
4. TROUBLE SHOOTING
LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4.1 Power on trouble
Power on sequence of HB620T is :
PWR key press → PM_ON_SW_N go to low (VA401, PM6650-3P KPDPWR_N pin#24) →
PM6650-3P Power Up → VREG_MSMC_1.2V(C436), VREG_MSME_1.8V(C433),
VREG_MSMP_2.7V(C423), VREG_MSMA_2.6V(C422), VREG_TCXO_2.85V(C413) power-
up → PON_RESET_N assert to MSM → Phone booting & PS_HOLD(D402) assert High to
PMIC(PM6650-3P)
Start
Battery voltg. higher
than 3.2V?
Press PWR key
Keypad LED on?
VA401 hig h t o low
when key press?
VREG_MSMC_1. 2V,
VREG_MSMP_2 . 7V, VREG_MSME_1 . 8
VREG_TCXO_2 . 8 5 V,
VREG_MSMA_2.6V p ow er up?
Is clock ok?
X101 : 19.2M
X401 : 32.768KHz
Change the Main board
Change or charging the
Battery
Follow the LED trouble
shoot
Check open Pattern
of power button
Check Dome Sheet
Change the Main board
Check the TXCO and SLEEP CRYSTAL
NO
YES
YES
YES
YES
YES
NO
NO
NO
NO
Start
Battery voltg. higher
than 3.2V?
Press PWR key
Keypad LED on?
VA401 hig h t o low
when key press
?
VREG_MSMC_1. 2V,
VREG_MSMP_2 . 7V, VREG_MSME_1 . 8V
VREG_TCXO_2 . 8 5 V,
VREG_MSMA_2.6V p ow er up?
Is clock ok?
X101 : 19.2M
X401 : 3
3
2.768KHz
Change the Main board
Change or charging the
Battery
Follow the LED trouble
shoot
Check open Pattern
of power button
Check Dome Sheet
Change the Main board
Check the TXCO and SLEEP CRYSTAL
NO
YES
YES
YES
YES
YES
NO
NO
NO
NO
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LG HB620 Specifications

General

Brand	LG
Model	HB620
Category	Cell Phone
Language	English