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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.................................16
2.5 RSSI BAR ..................................................17
2.6 Battery BAR ...............................................17
2.7 Sound Pressure Level ...............................18
2.8 Charging ....................................................18
3. TECHNICAL BRIEF............................19
3.1 General Description ...................................19
3.2 GSM Mode.................................................21
3.3 UMTS Mode...............................................25
3.4 LO generation and distribution circuits ......27
3.5 Off-chip RF Components ...........................27
3.6 Digital Baseband (DBB/MSM6280) ...........37
3.7 Subsystem(MSM6280) ..............................40
3.8 Power Block...............................................48
3.9 External memory interface.........................53
3.10 H/W Sub System .....................................55
3.11 Feature List..............................................72
3.12 Multimedia Chip Interface ........................78
3.13 Touch Screen Interface ...........................85
3.14 Main Features..........................................86
4. TROUBLE SHOOTING.......................93
4.1 RF Component ..........................................93
4.2 SIGNAL PATH ...........................................94
4.3 Checking VCTCXO Block ..........................96
4.4 Checking Front-End Module Block ............98
4.5 Checking UMTS Block.............................101
4.6 Checking GSM Block...............................106
4.7 Power on trouble......................................112
4.8 SIM detect trouble....................................117
4.9 Key sense trouble ( KEYPAD ) ................118
4.10 Keypad backlight trouble .......................120
4.11 Micro SD trouble ....................................122
4.12 Audio trouble..........................................123
4.13 Camera trouble ......................................136
4.14 Main LCD trouble...................................142
4.15 Bluetooth trouble....................................145
4.16 Bluetooth RF Test..................................146
4.17 Touch Screen trouble ............................147
5. DOWNLOAD.....................................148
5.1 Introduction ..............................................148
5.2 Downloading Procedure ..........................148
5.3 Troubleshooting Download Errors ..........161
5.4 Caution ....................................................166
6. BLOCK DIAGRAM ...........................167
6.1 GSM & UMTS RF Block ..........................167
6.2 Interface Diagram ....................................169
7. CIRCUIT DIAGRAM..........................171
8. BGA IC PIN MAP..............................183
9. PCB LAYOUT ...................................191
10. Calibration......................................199
10.1 Usage of Hot-Kimchi..............................199
11. EXPLODED VIEW & REPLACEMENT
PART LIST ..................................... 203
11.1 EXPLODED VIEW ................................ 203
11.2 Replacement Parts
<Mechanic component> ....................... 205
<Main component> ............................... 208
11.3 Accessory ............................................. 226
Table Of Contents
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Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Summary of Contents for U990
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