LG KF700Q, Service Manual, Page: 2 / 206

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1. INTRODUCTION .............................. 5
1.1 Purpose................................................... 5
1.2 Regulatory Information............................ 5
2. PERFORMANCE...............................7
2.1 Supporting Standard ................................7
2.2 Main Parts : Solution................................7
2.3 HW Features............................................8
2.4 HW SPEC. .............................................10
3. TECHNICAL BRIEF ........................16
3.1 General Description ...............................16
3.2 GSM Mode.............................................18
3.3 UMTS Mode...........................................21
3.4 LO generation and distribution circuits...23
3.5 Off-chip RF Components .......................24
3.6 Digital Base band (DBB/MSM6280).......34
3.7 Subsystem(MSM6280) ..........................36
3.8 Power Block ...........................................45
3.9 External memory interface .....................50
3.10 H/W Sub System..................................52
3.11 Feature List ..........................................63
3.12 Touch Screen Interface........................68
4. TROUBLE SHOOTING ...................69
4.1 Power on trouble....................................69
4.2 USB trouble............................................71
4.3 SIM detect trouble..................................72
4.4 Key sense trouble (KEYPAD) ................73
4.5 Keypad backlight trouble........................76
4.6 Micro SD trouble ....................................77
4.7 Audio trouble..........................................78
4.8 Camera trouble ......................................91
4.9 Main LCD trouble ...................................97
4.10 Bluetooth trouble................................100
4.11 Touch Screen trouble.........................102
4.12 RF Component...................................104
4.13 SIGNAL PATH ...................................105
4.14 Checking VCTCXO Block ..................107
4.15 Checking Front-End Module Block ....109
4.16 Checking UMTS Block .......................111
4.17 Checking GSM Block .........................124
5. DOWNLOAD .................................130
5.1 Introduction ..........................................130
5.2 Downloading Procedure.......................130
5.3 Troubleshooting Download Errors .......144
5.4 Caution.................................................149
6. BLOCK DIAGRAM ........................150
6.1 GSM & UMTS RF Block.......................150
6.2 Interface Diagram ................................152
7. Circuit Diagram ............................155
8. BGM Pin Map................................163
9. PCB LAYOUT ................................169
10. CALIBRATION & RF AUTO TEST
(HOT KIMCHI) .............................175
10.1 Usage of Hot-Kimchi ..........................175
11. EXPLODED VIEW &
REPLACEMENT PART LIST ......179
11.1 EXPLODED VIEW .............................179
11.2 Replacement Parts
<Mechanic component>.....................181
<Main component> ............................185
11.3 Accessory ..........................................205
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