LG TU550, Service Manual

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1. INTRODUCTION .............................. 5
1.1 Purpose................................................... 5
1.2 Regulatory Information............................ 5
2. PERFORMANCE...............................7
2.1 System Overview .....................................7
2.2 Usable environment .................................8
2.3 Radio Performance ..................................8
2.4 Current Consumption.............................14
2.5 RSSI BAR ..............................................14
2.6 Battery BAR ...........................................14
2.7 Sound Pressure Level............................15
2.8 Charging ................................................16
3. TECHNICAL BRIEF ........................17
3.1 General Description ...............................17
3.2 GSM Mode.............................................19
3.3 UMTS Mode...........................................22
3.4 LO Phase-locked Loop ..........................26
3.5 Off-chip RF Components .......................28
3.6 Digital Baseband(DBB/MSM6275).........35
3.7 Hardware Architecture ...........................36
3.8 Subsystem(MSM6275) ..........................38
3.9 Power Block ...........................................41
3.10 External memory interface ...................46
3.11 H/W Sub System..................................47
3.12 Main Features ......................................64
4. TROUBLE SHOOTING ...................69
4.1 RF Component.......................................69
4.2 SIGNAL PATH_UMTS RF .....................71
4.3 Checking VCXO Block ...........................73
4.4 Checking Ant. SW Module Block ...........75
4.5. Checking UMTS Block ..........................77
4.6. Checking GSM Block ............................84
4.7 Power ON Troubleshooting....................93
4.8 Charger Troubleshooting .......................95
4.9 USB Troubleshooting.............................98
4.10 SIM Detect Troubleshooting ..............100
4.11 Camera Troubleshooting ...................101
4.12 Keypad Backlight Troubleshooting ....102
4.13 Folder ON/OFF Troubleshooting .......103
4.14 Main LCD Troubleshooting ................104
4.15 Audio Receiver Path .........................105
4.16 Headset path......................................107
4.17 Speaker phone path...........................109
4.18 Main microphone ...............................111
4.19 Headset microphone..........................113
5. DOWNLOAD..................................115
5.1 Introduction ..........................................115
5.2 Downloading Procedure.......................115
5.3 Troubleshooting Download Errors .......129
5.4 Caution.................................................134
6. BLOCK DIAGRAM ........................135
6.1 GSM & UMTS RF Block.......................135
6.2 Interface Diagram ................................137
7. Circuit Diagram ............................137
8. pcb layout .....................................148
9. CALIBRATION ..............................153
9.1 HOT KIMCHI........................................153
9.2 How to use Hot Kimchi.........................157
9.3 HOT KIMCHI Example.........................158
10. EXPLODED VIEW &
REPLACEMENT PART LIST ..... 161
10.1 EXPLODED VIEW ............................ 161
10.2 Replacement Parts
<Mechanic component>.................... 163
<Main component> ........................... 166
10.3 Accessory ......................................... 185
Table Of Contents
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