LG FH6 Service Manual page 20

ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2
1. NO POWER PROBLEM ......................................................................................................................... 3-2
2. NO BOOTING WHEN YOU TURN THE UNIT ON, NO MESSAGE ON VFD ........................................ 3-5
3. NO AUDIO FROM SPEAKER ............................................................................................................... 3-12
4. NO SOUND ........................................................................................................................................... 3-13
5. BT CONNECTION ERROR .................................................................................................................. 3-16
6. NO LIGHTING (SPK LED, SPARKLING LED) ..................................................................................... 3-17
7. PROTECTION SYMPTOM OCCURRENCE......................................................................................... 3-18
ELECTRICAL TROUBLESHOOTING GUIDE ................................................................................................. 3-19
1. SYSTEM POWER SUPPLY ON SMPS BOARD .................................................................................. 3-19
2. POWER SUPPLY ON MAIN BOARD ................................................................................................... 3-22
3. SYSTEM PART ..................................................................................................................................... 3-26
4. NO AUDIO OUTPUT ............................................................................................................................ 3-27
5. PROTECTION MODE ........................................................................................................................... 3-30
6. NO LIGHTING ....................................................................................................................................... 3-31
WAVEFORMS OF MAJOR CHECK POINT .................................................................................................... 3-32
1. DSP (IC501) .......................................................................................................................................... 3-32
2. SDRAM (IC502) .................................................................................................................................... 3-33
3. SERIAL FLASH (IC504) ........................................................................................................................ 3-34
4. ADC (IC201) .......................................................................................................................................... 3-34
5. USB (CN102) ........................................................................................................................................ 3-35
6. BLUETOOTH (CN201) .......................................................................................................................... 3-35
WIRING DIAGRAM .......................................................................................................................................... 3-37
BLOCK DIAGRAMS ........................................................................................................................................ 3-39
1. SYSTEM BLOCK DIAGRAM ................................................................................................................ 3-39
2. SMPS BLOCK DIAGRAM ..................................................................................................................... 3-41
CIRCUIT DIAGRAMS ...................................................................................................................................... 3-43
1. SMPS CIRCUIT DIAGRAM .................................................................................................................. 3-43
2. MAIN - MICOM CIRCUIT DIAGRAM .................................................................................................... 3-45
3. MAIN - DSP CIRCUIT DIAGRAM ......................................................................................................... 3-47
4. MAIN - POWER CIRCUIT DIAGRAM ................................................................................................... 3-49
5. MAIN - ADC CIRCUIT DIAGRAM ......................................................................................................... 3-51
6. MAIN - PWM/ AMP CIRCUIT DIAGRAM .............................................................................................. 3-53
7. VFD CIRCUIT DIAGRAM...................................................................................................................... 3-55
8. MIC CIRCUIT DIAGRAM ...................................................................................................................... 3-57
9. CENTER LED UP CIRCUIT DIAGRAM ................................................................................................ 3-59
10. CENTER LED DOWN CIRCUIT DIAGRAM ......................................................................................... 3-61
11. SPK LED RIGHT CIRCUIT DIAGRAM ................................................................................................. 3-63
12. SPK LED LEFT CIRCUIT DIAGRAM.................................................................................................... 3-65
13. DJ KEY CIRCUIT DIAGRAM ................................................................................................................ 3-67
14. FRONT KEY CIRCUIT DIAGRAM ........................................................................................................ 3-69
CIRCUIT VOLTAGE CHART ........................................................................................................................... 3-71
1. IC VOLTAGE ......................................................................................................................................... 3-71
2. CAPACITOR VOLTAGE ....................................................................................................................... 3-72
3. CONNECTOR VOLTAGE ..................................................................................................................... 3-72
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-73
1. SMPS P. C. BOARD DIAGRAM ........................................................................................................... 3-73
2. MAIN P. C. BOARD DIAGRAM ............................................................................................................ 3-77
3. VFD P. C. BOARD DIAGRAM .............................................................................................................. 3-79
4. MIC P. C. BOARD DIAGRAM ............................................................................................................... 3-79
5. CENTER LED UP P. C. BOARD DIAGRAM ........................................................................................ 3-79
6. CENTER LED DOWN P. C. BOARD DIAGRAM .................................................................................. 3-81
7. SPK LED RIGHT P. C. BOARD DIAGRAM .......................................................................................... 3-81
8. SPK LED LEFT P. C. BOARD DIAGRAM ............................................................................................ 3-81
9. DJ KEY P. C. BOARD DIAGRAM ......................................................................................................... 3-83
10. FRONT KEY P. C. BOARD DIAGRAM ................................................................................................. 3-87
SECTION 3 ELECTRICAL
CONTENTS
3-1