LG CM9520, Service Manual

Page: 30 / 109

SECTION 3 ELECTRICAL
CONTENTS
TRAINING MASTER
................................................................................................................................... 3-2
1. NO SOUND FROM SPEAKERS ............................................................................................................ 3-2
2. NO SOUND IN AUX FUNCTION ............................................................................................................ 3-3
3. NO SOUND IN PORT. IN FUNCTION ................................................................................................... 3-4
4. NO SOUND IN IPOD FUNCTION .......................................................................................................... 3-5
5. NO SOUND IN AM/FM FUNCTION ....................................................................................................... 3-6
6. NO SOUND IN CD FUNCTION .............................................................................................................. 3-7
7. NO SOUND IN USB FUNCTION ............................................................................................................ 3-9
8. NO POWER .......................................................................................................................................... 3-10
ONE POINT REPAIR GUIDE
................................................................................................................. 3-11
1. NO POWER .......................................................................................................................................... 3-11
2. NO BOOTING WHEN POWER ON THE SET ..................................................................................... 3-13
3. VFD IS NOT DISPLAYED WHEN POWER ON THE SET ................................................................... 3-14
4. NO BOOTING IN CD/USB FUNCTION ................................................................................................ 3-15
5. NO OPERATION OF MD ..................................................................................................................... 3-20
6. NO SOUND .......................................................................................................................................... 3-26
ELECTRICAL TROUBLESHOOTING GUIDE
.................................................................................. 3-35
1. POWER SUPPLY ON SMPS BOARD ................................................................................................. 3-35
2. SYSTEM PART .................................................................................................................................... 3-39
3. NO AUDIO PART ................................................................................................................................. 3-40
4. DIGITAL AUDIO AMP CHECK ............................................................................................................. 3-45
5. NO LIGHTING (WOOFER SPEAKER) ................................................................................................. 3-46
WAVEFORMS
............................................................................................................................................. 3-47
WIRING DIAGRAM
................................................................................................................................... 3-53
BLOCK DIAGRAMS
................................................................................................................................. 3-55
1. SMPS BLOCK DIAGRAM..................................................................................................................... 3-55
2. MAIN SYSTEM BLOCK DIAGRAM ...................................................................................................... 3-57
CIRCUIT DIAGRAMS
............................................................................................................................... 3-59
1. SMPS CIRCUIT DIAGRAM .................................................................................................................. 3-59
2. MAIN - MICOM CIRCUIT DIAGRAM .................................................................................................... 3-61
3. MAIN - PWM / FILTER CIRCUIT DIAGRAM ........................................................................................ 3-63
4. MAIN - IR AMP CIRCUIT DIAGRAM ................................................................................................... 3-65
5. MAIN - DSP / USB / IPOD CIRCUIT DIAGRAM .................................................................................. 3-67
6. MAIN - RF SERVO CIRCUIT DIAGRAM ............................................................................................. 3-69
7. MAIN - ADC CIRCUIT DIAGRAM ........................................................................................................ 3-71
8. MAIN - BEAT BOX CIRCUIT DIAGRAM .............................................................................................. 3-73
9. FRONT - VFD CIRCUIT DIAGRAM ..................................................................................................... 3-75
10. FRONT - VOLUME CIRCUIT DIAGRAM ............................................................................................. 3-77
11. FRONT - USB CIRCUIT DIAGRAM ..................................................................................................... 3-79
12. FRONT - MIC CIRCUIT DIAGRAM ...................................................................................................... 3-81
13. IPOD CIRCUIT DIAGRAM .................................................................................................................... 3-83
CIRCUIT VOLTAGE CHART
................................................................................................................. 3-85
PRINTED CIRCUIT BOARD DIAGRAMS
......................................................................................... 3-89
1. SMPS P.C.BOARD ............................................................................................................................... 3-89
2. MAIN P.C.BOARD ................................................................................................................................ 3-93
3. FRONT_VFD P.C.BOARD ................................................................................................................... 3-97
4. FRONT_USB P.C.BOARD ................................................................................................................... 3-99
5. FRONT_MIC P.C.BOARD .................................................................................................................... 3-99
6. FRONT_VOLUME P.C.BOARD ......................................................................................................... 3-101
7. IPOD P.C.BOARD .............................................................................................................................. 3-105
3-1