LG BH4120SN Service Manual page 10

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. BD-HTS ........................................................... 2-26
ONE POINT REPAIR GUIDE ............................. 2-27
1. NO POWER PROBLEM .................................. 2-27
2. NO BOOTING WHEN YOU TURN THE
UNIT ON, NO MESSAGE OR "PLEASE
WAIT"ON FRONT PANEL .............................. 2-29
3. BAD HDMI VIDEO / AUDIO OUTPUT ............ 2-38
4. NO SPEAKER OUTPUT ................................. 2-39
ELECTRICAL TROUBLESHOOTING GUIDE .. 2-40
1. SYSTEM POWER SUPPLY ON
SMPS BOARD ................................................ 2-40
2. AMP POWER SUPPLY ON SMPS BOARD ... 2-41
3. POWER SUPPLY ON MAIN BOARD ............. 2-42
4. SYSTEM PART ............................................... 2-43
5. NO CVBS VIDEO OUTPUT ............................ 2-44
6. NO AUDIO OUTPUT ....................................... 2-44
7. NO HDMI OUTPUT ......................................... 2-46
WAVEFORMS ...................................................... 2-47
1. SYSTEM PART - 1 ......................................... 2-47
2. SYSTEM PART - 2 (SYSTEM MEMORY) ...... 2-48
3. VIDEO PART (100 % FULL COLOR - BAR) .. 2-49
4. AUDIO PART (I2S) ......................................... 2-49
5. HDMI PART .................................................... 2-50
SECTION 2 ELECTRICAL
CONTENTS
WIRING DIAGRAM ............................................. 2-53
BLOCK DIAGRAM .............................................. 2-55
CIRCUIT DIAGRAMS ......................................... 2-57
1. SMPS - POWER CIRCUIT DIAGRAM ............ 2-57
2. MAIN - CPU CIRCUIT DIAGRAM ................... 2-59
3. MAIN - MEMORY CIRCUIT DIAGRAM .......... 2-61
4. MAIN - LOADER CIRCUIT DIAGRAM ............ 2-63
5. MAIN - MICOM CIRCUIT DIAGRAM .............. 2-65
6. MAIN - HDMI CIRCUIT DIAGRAM ................. 2-67
7. MAIN - ADC/DIR CIRCUIT DIAGRAM ............ 2-69
8. MAIN - DSP CIRCUIT DIAGRAM ................... 2-71
9. MAIN - POWER CIRCUIT DIAGRAM ............. 2-73
10. MAIN - I/O CIRCUIT DIAGRAM ...................... 2-75
11. PWM & AMP CIRCUIT DIAGRAM .................. 2-77
12. JACK CIRCUIT DIAGRAM .............................. 2-79
13. FRONT CIRCUIT DIAGRAM .......................... 2-81
CIRCUIT VOLTAGE CHART ............................. 2-83
PRINTED CIRCUIT BOARD DIAGRAMS ......... 2-85
1. SMPS P. C. BOARD ....................................... 2-85
2. MAIN P. C. BOARD ........................................ 2-87
3. AMP P.C.BOARD ............................................ 2-89
4. JACK P. C. BOARD ........................................ 2-91
5. FRONT P. C. BOARD ..................................... 2-91
2-1