LG SH5B Service Manual page 22

ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2
1. NO POWER PROBLEM (PVDD) ............................................................................................................ 3-2
2. POWER ON ERROR .............................................................................................................................. 3-3
3. NO SOUND (PORTABLE FUNCTION) .................................................................................................. 3-5
4. NO WIRELESS ....................................................................................................................................... 3-6
5. NO BLUETOOTH .................................................................................................................................... 3-7
6. NO SOUND (USB) .................................................................................................................................. 3-8
7. NO SOUND (OPTICAL) .......................................................................................................................... 3-9
8. HDMI PROBLEM .................................................................................................................................. 3-10
9. D(DC) PROTECTION ........................................................................................................................... 3-11
10. S(SHUT DOWN) PROTECTION ........................................................................................................... 3-12
11. B(BURNT) PROTECTION .................................................................................................................... 3-13
WAVEFORMS OF MAJOR CHECK POINT .................................................................................................... 3-14
1. CRYSTAL .............................................................................................................................................. 3-14
2. FLASH MEMORY ................................................................................................................................. 3-15
3. TACT KEY ............................................................................................................................................. 3-16
4. USB ....................................................................................................................................................... 3-17
5. REMOTE CONTROL ............................................................................................................................ 3-18
6. OPTICAL ............................................................................................................................................... 3-19
7. PORTABLE ........................................................................................................................................... 3-20
8. AUDIO PWM ......................................................................................................................................... 3-21
WIRING DIAGRAM .......................................................................................................................................... 3-23
BLOCK DIAGRAM .......................................................................................................................................... 3-25
CIRCUIT DIAGRAMS ...................................................................................................................................... 3-27
1. MAIN - DSP CIRCUIT DIAGRAM ......................................................................................................... 3-27
2. MAIN - PWM & AMP CIRCUIT DIAGRAM ........................................................................................... 3-29
3. MAIN - POWER CIRCUIT DIAGRAM ................................................................................................... 3-31
4. MAIN - HDMI & JACK CIRCUIT DIAGRAM ......................................................................................... 3-33
5. FRONT CIRCUIT DIAGRAM ................................................................................................................ 3-35
6. KEY CIRCUIT DIAGRAM ..................................................................................................................... 3-37
CIRCUIT VOLTAGE CHART ........................................................................................................................... 3-39
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-41
1. MAIN P. C. BOARD DIAGRAM ............................................................................................................ 3-41
2. FRONT P. C. BOARD DIAGRAM ......................................................................................................... 3-43
3. KEY P. C. BOARD DIAGRAM .............................................................................................................. 3-43
SECTION 3
ELECTRICAL
CONTENTS
3-1