Table Of Contents - LG TracFone LG840G Service Manual

1. INTRODUCTION ..................................................................... 3
1.1 Purpose ....................................................................................................3
1.2 Regulatory Information ....................................................................3
1.3 Abbreviations ........................................................................................5
2. PERFORMANCE ...................................................................... 7
2.1 System ......................................................................................................7
2.2 Using Conditio ......................................................................................7
2.3 Accessary ................................................................................................7
2.4 Network ...................................................................................................8
2.5 Current Consumption ..................................................................... 13
2.6 Usage Time ( AT & T spec) .............................................................. 13
2.7 RSSI ......................................................................................................... 13
2.8 Battery Bar ........................................................................................... 14
2.9 Heat Emissio ....................................................................................... 14
2.10 Color Temperature ......................................................................... 14
2.11 LG840G Figure ................................................................................. 15
3. TECHNICAL BRIEF ................................................................ 16
3.1 RF Technical Description................................................................ 16
3.2 WCDMA Part ....................................................................................... 17
3.3 EDGE/GPRS/GSM RF block ............................................................ 23
3.4 Control Flow ....................................................................................... 29
3.5 BB Technica Description ................................................................ 30
3.6 Power management ........................................................................ 42
4. TROUBLE SHOOTING .......................................................... 45
4.1 RF Component................................................................................... 45
4.2 RF Path .................................................................................................. 47
4.3 Trouble Shooting of GSM Part (GSM850/900/1800/1900)
......................................................................................................................... 49
4.4 Trouble Shooting of WCDMA Part ............................................. 58
4.5 Checking Bluetooth Block ............................................................ 66
4.6 Checking WiFi Block ........................................................................ 69
4.7 Checking GPS Block ......................................................................... 72
4.8 Power ON Troubleshooting .......................................................... 76
LGE Internal Use Only

Table Of Contents

4.9 Charger Troubleshooting .............................................................. 79
4.10 USB Troubleshooting .................................................................... 80
4.11 USIM Detect Troubleshooting .................................................. 82
4.12 Camera Troubleshooting ............................................................ 85
4.13 Main Keypad Backlight Troubleshooting ............................. 87
4.14 LCD Troubleshooting .................................................................... 88
4.15 Vibrator ............................................................................................... 90
4.16 Receiver Path ................................................................................... 91
4.17 Headset path ................................................................................... 93
4.18 Speaker phone path ..................................................................... 95
4.19 Main microphone .......................................................................... 97
4.20 Headset microphone .................................................................... 99
5. DOWNLOAD .......................................................................101
6. BLOCK DIAGRAM ...............................................................120
7. CIRCUIT DIAGRAM ............................................................130
8. BGA PIN MAP .....................................................................141
9. PCB LAYOUT .......................................................................145
10. CALIBRATION ...................................................................153
10.1 Configuration of Tachyon .........................................................153
10.2 How to use Tachyon ....................................................................156
11. EXPLODED VIEW & REPLACEMENT PART LIST .............158
11.1 EXPLODED VIEW ...........................................................................158
11.2 Replacement Parts.......................................................................161
11.3 Accessory ........................................................................................186
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Only for training and service purposes