Checking Tcxo Block - LG CT815 Service Manual

4.3 Checking TCXO Block

The output frequency (19.2MHz) of TCXO (X101) is used as the reference one of RTR6285 and
PM7540 internal VCO.
TP1
VREG_TCXO_2.85V
C65
0.1u
R117
RTR_TRK_LO_ADJ
100ohm
TP2
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
TP1
TP1
TCXO Circuit
C64
1000p
X101
4 3
VDD OUT
1 2
VCONT GND
19.2MHz
C67 EXSK0005704
0.01u DSA321SCA
Schematic of the Crystal Part (19.2MHz)
- 79 -
4. TROUBLE SHOOTING
TP1
TP3
C66 100p
TCXO_PM_19.2MHz
C70 1000p
TCXO_RTR_19.2MHz
R122 100K
TC7SH04FS
VCC
5
C73 100p
1 4
2
U103
GND
VREG_MSME_1.8V
C71
0.1u
R126
USBH_REF_CLK
33
C74
100p
LGE Internal Use Only