Table Of Contents; Only For Training And Service Purposes - LG KC780 Service Manual

1. INTRODUCTION ............................................... 9
1.1 Purpose ......................................................................9
1.2 Regulatory Information .................................................9
2. PERFORMANCE ............................................. 11
2.1 H/W Feature..............................................................11
2.2 Technical specifi cation ...............................................12
3. TECHNICAL BRIEF ......................................... 18
3.1 KC780 Component Block diagram. .............................18
3.2 Main Chip Introduction ...............................................19
3.3 Baseband Part Introduction ........................................21
3.4 Power Management Unit ............................................32
3.5 Power ON/OFF ..........................................................36
3.6 SIM interface .............................................................39
3.7 Memory ....................................................................40
3.8 LCD Display ..............................................................41
3.9 Keypad Switching & Scanning ....................................43
3.10 Keypad back-light illumination ..................................45
3.11 LCD back-light illumination ......................................45
3.12 JTAG interface connector .........................................48
3.13 Audio ......................................................................49
3.14 USB charging circuit ................................................53
3.15 BLUETOOTH ............................................................54
3.16 FM Radio ................................................................56
3.17 Micro SD external memory card slot .........................57
3.18 18pin Multi Media Interface connector ......................59
3.19 General Description .................................................61
3.20 Receiver part ...........................................................62
3.21 Transmitter part .......................................................63
3.22 RF synthesizer .........................................................64
3.23 DCXO .....................................................................64
3.24 Front End Module control .........................................64
3.25 Power Amplifi er Module ...........................................66
3.26 Mode Selection .......................................................66
4. PCB layout .................................................... 67
4.1 Main PCB component placement ................................67
5. TROUBLE SHOOTING ..................................... 71
5.1 Trouble shooting test setup ........................................71
5.2 Power on Trouble .......................................................72
Copyright © 2008 LG Electronics. Inc. All right reserved.

Only for training and service purposes

Table Of Contents

5.3 Charging trouble........................................................75
5.4 LCD display trouble ...................................................77
5.5 Camera Trouble .........................................................80
5.6 Receiver & Speaker trouble ........................................82
5.7 Microphone trouble ...................................................84
5.8 Ear-MIC Jack Detection trouble ..................................85
5.9 Vibrator trouble ..........................................................86
5.10 Keypad back light trouble .........................................87
5.11 SIM & uSD trouble ...................................................90
5.12 RF Troubleshooting ..................................................94
5.13 RF Receiver path Troubleshooting .............................99
5.14 RF Transmitter path Troubleshooting .......................102
6. Download & S/W upgrade ......................... 107
6.1 S/W download setup ................................................107
6.2 Download program user guide ..................................108
7. BLOCK DIAGRAM ........................................ 110
8. CIRCUIT DIAGRAM ...................................... 111
9. BGA Pin Map .............................................. 121
10. PCB LAYOUT ............................................. 127
11. RF Calibration .......................................... 137
11.1 Test Equipment Setup ............................................137
11.2 Calibration Step .....................................................137
12. STAND-ALONE TEST ................................. 142
12.1 Test Program Setting .............................................142
12.2 Tx Test ..................................................................144
12.3 Rx Test ..................................................................145
13. ENGINEERING MODE ................................. 147
14. EXPLODED VIEW & REPLACEMENT
PART LIST ................................................. 149
- 5 - LGE Internal Use Only