LG DM5620K Service Manual page 20

ELECTRICAL TROUBLESHOOTING GUIDE
1. SMPS PART ........................................................................................................................................... 3-2
2. AUDIO ABNORMAL ................................................................................................................................ 3-4
3. FUNCTION MODE AUDIO ABNORMAL ................................................................................................ 3-5
4. CD PART ................................................................................................................................................ 3-7
5. DVD READING CHECK ......................................................................................................................... 3-8
6. USB PART .............................................................................................................................................. 3-9
7. VFD DISPLAY CHECK ......................................................................................................................... 3-10
WAVEFORMS OF MAJOR CHECK POINT
1. WHEN POWER ON, RESET & DATA ETC WAVEFORM ................................................................... 3-11
2. WHEN USB FUNCTION OPERATING ................................................................................................. 3-11
3. STARTING ACTION WAVEFORM IN MD DEVICE (SLED HOME) .................................................... 3-12
4. FOCUS WAVEFORM ........................................................................................................................... 3-13
5. SPINDLE KICK SIGNAL ....................................................................................................................... 3-15
6. AT FIRST ACTION, FOCUS SIGNAL A, B, C, D ................................................................................. 3-16
7. RF WAVEFORM (ANALOG SCOPE) ................................................................................................... 3-16
WIRING DIAGRAM
.................................................................................................................................... 3-17
BLOCK DIAGRAM
.................................................................................................................................... 3-19
CIRCUIT DIAGRAMS
1. SMPS CIRCUIT DIAGRAM .................................................................................................................. 3-21
2. DVD MPEG/ ADC/ COMPOSITE/ USB CIRCUIT DIAGRAM............................................................... 3-23
3. S3050/ S8082/ MIC CIRCUIT DIAGRAM ............................................................................................. 3-25
4. DSP/ SPBANA/ HEADPHONE CIRCUIT DIAGRAM ............................................................................ 3-27
5. AMPLIFIER CIRCUIT DIAGRAM .......................................................................................................... 3-29
6. MCU/ TUNER/ AUX CIRCUIT DIAGRAM............................................................................................. 3-31
7. VFD/ KEY/ LED CIRCUIT DIAGRAM ................................................................................................... 3-33
8. TAPE CIRCUIT DIAGRAM (OPTIONAL PART) ................................................................................... 3-35
CIRCUIT VOLTAGE CHART
1. ICs ......................................................................................................................................................... 3-37
2. CAPACITORS ....................................................................................................................................... 3-37
3. CONNECTORS ..................................................................................................................................... 3-39
PRINTED CIRCUIT BOARD DIAGRAMS
1. SMPS P.C.BOARD ............................................................................................................................... 3-41
2. MAIN P.C.BOARD ................................................................................................................................ 3-43
3. VFD / USB P.C.BOARD ........................................................................................................................ 3-47
4. KEY_L P.C.BOARD .............................................................................................................................. 3-48
5. KEY_R P.C.BOARD .............................................................................................................................. 3-48
6. MIC P.C.BOARD ................................................................................................................................... 3-49
7. KEY P.C.BOARD .................................................................................................................................. 3-50
SECTION 3
ELECTRICAL
CONTENTS
............................................................................................................................... 3-21
................................................................................................................. 3-37
.......................................................................................... 3-41
.................................................................................... 3-2
...................................................................................... 3-11
3-1