LG KT878 Service Manual page 90

1. 检查 LDO 电路
测试点
电路图
AP_VUSBIN
VUSB_ABB VGP_ABB
VAPP_ABB
VABB_ABB
C331 C330 C341 C340
2.2u 1u 1u 10u
(10v)
VEXT_RF
BLM21PG300SN1(2012)
VEXT_ABB
VSIM_ABB
VPLL_ABB
VRTC_ABB
VRF_ABB
VMIC_ABB
C332 C333 C334 C335 C336 C337
1u 1u 1u 1u 1u 0.1u
VEXT_ABB
FB201
- 89 -
VLL_ABB
C338 C339
1u 1u
VBAT_RF
FB202
BLM21PG300SN1(2012)
4.故障解决
M6
VSDGND1
L6
VSDGND2
N1
VINT1
P1
VINT2
L1
VLL1
R306 NA M1
VLL2
K1
VLLFB
A4
VEXTI
B4
VEXT2
U30
AD685
N8
VRTCSEL
P8
VRTC
P7
VSIM
K12
VMIC
E4
VPLL
D12
VRF
A1
VGP
G13
VABB
D13
VUSBIN
E13
VUSB
D14
VAPP
E12
VAPPGATE
M12
PWREN
C342
100N
(NA)
VBAT