LG LAS950M - Section 2: Electrical

2-1
SECTION 2
ELECTRICAL
CONTENTS
ONE POINT REPAIR GUIDE ............................................................................................................................ 2-2
1. NO POWER PROBLEM. ........................................................................................................................ 2-2
2. NO BOOTING WHEN YOU TURN THE UNIT ON, NO MESSAGE OR
“HELLO” ON FRONT PANEL ................................................................................................................. 2-4
3. NO SOUND ............................................................................................................................................. 2-7
ELECTRICAL TROUBLESHOOTING GUIDE ................................................................................................. 2-12
1. POWER SUPPLY ON SMPS BOARD .................................................................................................. 2-12
2. POWER SUPPLY ON MAIN BOARD ................................................................................................... 2-13
3. SYSTEM PART ..................................................................................................................................... 2-19
4. NO AUDIO OUTPUT ............................................................................................................................ 2-21
5. NO HDMI OUTPUT ............................................................................................................................... 2-23
WAVEFORMS OF MAJOR CHECK POINT .................................................................................................... 2-24
1. ADC I2S WAVEFORM (IC200) ............................................................................................................. 2-24
2. DSP OUTPUT I2S WAVEFORM (IC600) ............................................................................................. 2-25
3. LCD DATA LINE OUTPUT WAVEFORM (IC100) ................................................................................ 2-26
4. RMC WAVEFORM ................................................................................................................................ 2-27
5. I2C WAVEFORM .................................................................................................................................. 2-28
WIRING DIAGRAM .......................................................................................................................................... 2-31
BLOCK DIAGRAMS ........................................................................................................................................ 2-33
1. POWER BLOCK DIAGRAM ................................................................................................................. 2-33
2. SYSTEM BLOCK DIAGRAM ................................................................................................................ 2-35
CIRCUIT DIAGRAMS ...................................................................................................................................... 2-37
1. SMPS CIRCUIT DIAGRAM .................................................................................................................. 2-37
2. MAIN - MICOM CIRCUIT DIAGRAM .................................................................................................... 2-39
3. MAIN - MPEG CIRCUIT DIAGRAM ...................................................................................................... 2-41
4. MAIN - MEMORY CIRCUIT DIAGRAM ................................................................................................ 2-43
5. MAIN - ADC & I/O CIRCUIT DIAGRAM ............................................................................................... 2-45
6. MAIN - DCDC CIRCUIT DIAGRAM ...................................................................................................... 2-47
7. MAIN - DSP CIRCUIT DIAGRAM ......................................................................................................... 2-49
8. MAIN - DAC / AMP CIRCUIT DIAGRAM .............................................................................................. 2-51
9. HDMI CIRCUIT DIAGRAM.................................................................................................................... 2-53
10. FRONT CIRCUIT DIAGRAM ................................................................................................................ 2-55
11. KEY CIRCUIT DIAGRAM...................................................................................................................... 2-57
CIRCUIT VOLTAGE CHART ........................................................................................................................... 2-59
1. ICs ......................................................................................................................................................... 2-59
2. CAPACITORS ....................................................................................................................................... 2-61
3. CONNECTORS ..................................................................................................................................... 2-62
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 2-63
1. SMPS P. C. BOARD DIAGRAM ........................................................................................................... 2-63
2. MAIN P. C. BOARD DIAGRAM ............................................................................................................ 2-65
3. HDMI P. C. BOARD DIAGRAM ............................................................................................................ 2-67
4. FRONT P. C. BOARD DIAGRAM ......................................................................................................... 2-67
5. KEY P. C. BOARD DIAGRAM .............................................................................................................. 2-67