LG LAB550H Service Manual page 14

DIGITAL DISPLAY & MEDIA TRAINING MASTER ......................................................................................... 2-2
1. DISTORTED PICTURE ........................................................................................................................... 2-2
2. NO PICTURE .......................................................................................................................................... 2-7
3. PICTURE COLOR ................................................................................................................................. 2-12
4. NOISE/AUDIO PROBLEMS .................................................................................................................. 2-14
5. MISCELLANEOUS ................................................................................................................................ 2-17
6. BLU-RAY PLAYER ............................................................................................................................... 2-26
ONE POINT REPAIR GUIDE .......................................................................................................................... 2-27
1. NO POWER .......................................................................................................................................... 2-27
2. NO BOOTING ....................................................................................................................................... 2-29
3. WIRED NETWORK CONNECTION ERROR ....................................................................................... 2-35
4. WIRELESS NETWORK CONNECTION ERROR ................................................................................. 2-36
5. BAD HDMI VIDEO / AUDIO OUTPUT .................................................................................................. 2-37
6. NO AUDIO FROM SPEAKER ............................................................................................................... 2-38
7. NO USB ................................................................................................................................................ 2-39
8. BT CONNECTION ERROR .................................................................................................................. 2-40
ELECTRICAL TROUBLESHOOTING GUIDE ................................................................................................. 2-41
1. POWER SUPPLY ON SMPS BOARD .................................................................................................. 2-41
2. POWER SUPPLY ON MAIN BOARD ................................................................................................... 2-42
3. SYSTEM PART ..................................................................................................................................... 2-46
4. NO HDMI OUTPUT ............................................................................................................................... 2-48
5. NO AUDIO OUTPUT ............................................................................................................................ 2-49
WAVEFORMS OF MAJOR CHECK POINT .................................................................................................... 2-50
1. SYSTEM PART - 1 (MPEG CRYSTAL 27 MHz) .................................................................................. 2-50
2. SYSTEM PART - 2 (DDR3 MEMORY) ................................................................................................. 2-51
3. AUDIO PART - 1 (DSP I2C) ................................................................................................................. 2-52
4. AUDIO PART - 2 (DSP I2S) ................................................................................................................. 2-53
5. HDMI PART .......................................................................................................................................... 2-54
WIRING DIAGRAM .......................................................................................................................................... 2-55
BLOCK DIAGRAM .......................................................................................................................................... 2-57
CIRCUIT DIAGRAMS ...................................................................................................................................... 2-59
1. SMPS CIRCUIT DIAGRAM .................................................................................................................. 2-59
2. MAIN - MICOM CIRCUIT DIAGRAM .................................................................................................... 2-61
3. MAIN - POWER CIRCUIT DIAGRAM ................................................................................................... 2-63
4. MAIN - MPEG / MEMORY CIRCUIT DIAGRAM .................................................................................. 2-65
5. MAIN - F/E CIRCUIT DIAGRAM ........................................................................................................... 2-67
6. MAIN - DAC / AMP CIRCUIT DIAGRAM .............................................................................................. 2-69
7. MAIN - HDMI CIRCUIT DIAGRAM ....................................................................................................... 2-71
8. MAIN - MULTI OPTION CIRCUIT DIAGRAM ....................................................................................... 2-73
9. FRONT CIRCUIT DIAGRAM ................................................................................................................ 2-75
10. FRONT KEY CIRCUIT DIAGRAM ........................................................................................................ 2-77
CIRCUIT VOLTAGE CHART ........................................................................................................................... 2-79
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 2-81
1. SMPS P. C. BOARD ............................................................................................................................. 2-81
2. MAIN P. C. BOARD .............................................................................................................................. 2-83
3. FRONT P. C. BOARD ........................................................................................................................... 2-85
4. FRONT KEY P. C. BOARD .................................................................................................................. 2-85
SECTION 2
ELECTRICAL
CONTENTS
2-1