LG KG280 Service Manual - Page 42

Test Point, Checking Flow, Circuit, Waveform

Get LG KG280 PDF manuals and user guides View all LG KG280 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 42 highlights

4. TROUBLE SHOOTING (1) Checking VCTCXO Circuit TEST POINT X600.4 (VCC) X600 CIRCUIT CHECKING FLOW Check Pin 3. 26 MHzO.K? Refer to Graph 4-1(b) No Check Pin 4. 2.75V OK? Refer to Graph 4-1(a) No X600.3 (OUT) Check U101 Yes VCTCXO Circuit is OK See next Page to check Mobile SW Yes Changing X600 X600 (b) 2V75_VVCXO AFC R622 15K 1 VCONT OUT 3 C647 1000p 2 GND VCC 4 26MHz C648 (a) TG-5010LH-26M 2.2u EXSK0008101 WAVEFORM Graph 4-1(a) Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes - 43 - Graph 4-1(b) LGE Internal Use Only

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
LGE Internal Use Only
Copyright © 2007 LG Electronics. Inc.
All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
- 43 -
(1) Checking VCTCXO Circuit
X600.3
(OUT)
X600.4
(VCC)
X600
Check Pin 3.
Refer to Graph 4-1(b)
26 MHzO.K?
No
No
VCTCXO Circuit is OK
See next Page to check
Mobile SW
VCTCXO Circuit is OK
See next Page to check
Mobile SW
Yes
Check Pin 4.
Refer to Graph 4-1(a)
2.75V OK?
No
Yes
Changing X600
Check U101
2.2u
C648
C647
1000p
2V75_VVCXO
2
GND
3
OUT
VCC
4
VCONT
1
26MHz
TG-5010LH-26M
EXSK0008101
X600
R622
15K
AFC
TEST POINT
CHECKING FLOW
CIRCUIT
WAVEFORM
Graph 4-1(a)
Graph 4-1(b)
(b)
(a)