LG DP122 Service Manual page 16

ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2
1. NO BOOTING ......................................................................................................................................... 3-2
2. NO VIDEO OUTPUT ............................................................................................................................... 3-7
3. NO AUDIO OUTPUT .............................................................................................................................. 3-8
ELECTRICAL TROUBLESHOOTING GUIDE ................................................................................................... 3-9
1. SMPS TROUBLESHOOTING FLOW ..................................................................................................... 3-9
2. POWER CHECK FLOW ....................................................................................................................... 3-11
3. SYSTEM OPERATION FLOW .............................................................................................................. 3-12
4. SYSTEM TEST FLOW .......................................................................................................................... 3-13
DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING ....................................................... 3-19
1. SYSTEM 27MHZ CLOCK, RESET, FLASH R/W SIGNAL ................................................................... 3-19
2. SDRAM CLOCK .................................................................................................................................... 3-21
3. TRAY OPEN/CLOSE SIGNAL .............................................................................................................. 3-21
4. SLED CONTROL RELATED SIGNAL (NO DISC CONDITION) .......................................................... 3-22
5. LENS CONTROL RELATED SIGNAL (NO DISC CONDITION) .......................................................... 3-22
6. LASER POWER CONTROL RELATED SIGNAL (NO DISC CONDITION) ......................................... 3-23
7. SPINDLE CONTROL WAVEFORM (NO DISC CONDITION) .............................................................. 3-23
8. FOCUS ON WAVEFORM ..................................................................................................................... 3-24
9. TRACKING CONTROL RELATED SIGNAL (SYSTEM CHECKING) ................................................... 3-25
10. MT1389V AUDIO COAXIAL OUTPUT (SPDIF).................................................................................... 3-26
11. MT1389V VIDEO OUTPUT WAVEFORM ............................................................................................ 3-26
12. AUDIO OUTPUT FROM MT1389V ....................................................................................................... 3-27
WIRING DIAGRAM .......................................................................................................................................... 3-28
BLOCK DIAGRAMS ........................................................................................................................................ 3-29
1. OVERALL BLOCK DIAGRAM .............................................................................................................. 3-29
2. SMPS & KEY BLOCK DIAGRAM ......................................................................................................... 3-30
3. POWER BLOCK DIAGRAM ................................................................................................................. 3-31
4. SYSTEM BLOCK DIAGRAM ................................................................................................................ 3-32
5. SERVO BLOCK DIAGRAM .................................................................................................................. 3-33
6. A/V BLOCK DIAGRAM ......................................................................................................................... 3-34
CIRCUIT DIAGRAMS ...................................................................................................................................... 3-35
1. SMPS & KEY / LED CIRCUIT DIAGRAM ............................................................................................ 3-35
2. MAIN-MPEG CIRCUIT DIAGRAM ........................................................................................................ 3-37
3. MAIN-SERVO CIRCUIT DIAGRAM ...................................................................................................... 3-39
4. MAIN-AV CIRCUIT DIAGRAM .............................................................................................................. 3-41
CIRCUIT VOLTAGE CHART ........................................................................................................................... 3-43
1. ICs ......................................................................................................................................................... 3-43
2. TRs ........................................................................................................................................................ 3-45
3. CAPACITORS ....................................................................................................................................... 3-45
4. CONNECTORS ..................................................................................................................................... 3-46
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-47
1. MAIN P.C.BOARD ................................................................................................................................ 3-47
2. SMPS & KEY / LED P.C.BOARD ......................................................................................................... 3-49
SECTION 3
ELECTRICAL
CONTENTS
3-1