LG U250 manuals

Lg U250 User Manual (175 pages)

Brand: Lg | Category: Mobile phones | Size: 5.46 MB |

English

Table of contents

Service Manual

1

Table Of Contents

2

1. INTRODUCTION

4

2.2 Usable environment

7

2.3 Radio Performance

7

2. PERFORMANCE

10

2.4 Current Consumption

13

2.5 RSSI BAR

13

2.6 Battery BAR

14

2.7 Sound Pressure Level

15

2.8 Charging

15

3. TECHNICAL BRIEF

16

3.2 GSM Mode

18

3.3 UMTS Mode

22

3.5 Off-chip RF Components

24

3. BB Technical Description

33

3.7 Block Diagram(MSM6245)

35

3.8 Subsystem(MSM6245)

36

3.9 Power Block

44

3.11 H/W Sub System

51

KEY_BACK_LIGHT LED(8EA)

60

(+16.5dB)

62

SELECT_SPK&RCV

64

Audio AMP

65

3.12 Main Features

67

Bluetoot

68

4.2 SIGNAL PATH_UMTS RF

74

4.3 SIGNAL PATH_GSM RF

75

4.4 Checking VC-TCXO Block

76

TP1 VREG RF SMPS

79

GSM 1800 / GSM1900 RX

79

GSM 900 RX

79

GSM 900 TX / WCDMA

79

GSM 1800 / GSM 1900 TX

79

VREG_TCXO_2.85

82

4.7 Checking GSM Block

85

TP1. DCS RX INPUT

89

TP2. PCS RX INPUT

89

TP3. GSM RX INPUT

89

4.8 Checking Bluetooth Block

91

4.9 Power ON Troubleshooting

93

4.10 Charger Troubleshooting

95

Is the TA (or USB Cable)

96

Is it charging properly

96

, Q302?

96

4.11 USB Troubleshooting

98

VREG_UIM_2.85V is 2.85V?

99

USIM_P_CLK is run?

99

4. TROUBLE SHOOTING

100

Change the Main board

101

4.15 Main LCD Troubleshooting

105

4.16 Receiver Path

106

4.17 Headset path

108

4.18 Speaker phone path

110

Audio Amp

111

Analog Switch

111

4.19 Main microphone

112

4.20 Headset microphone

114

4.21 Vibrator

116

MOTOR_PWR

117

5. DOWNLOAD

118

NV_U250/KU250

124

6. BLOCK DIAGRAM

133

6.2 Interface Diagram

135

7. CIRCUIT DIAGRAM

142

MEM & POWER

144

8. PCB LAYOUT

146

9.2 How to use HOT KIMCHI

151

Select "U250/KU250"

152

Click "Start"

152

10. Factory Test Mode

153

10.2. WCDMA Test Mode

154

10.3. GSM Test Mode

155

11.1 EXPLODED VIEW

156

11.2 Replacement Parts

158

<Mechanic component>

158

<Main component>

160

11.3 Accessory

173

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