LG CM9730 Service Manual

SECTION 3 ELECTRICAL
CONTENTS
ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2
1. NO POWER ............................................................................................................................................ 3-2
2. NO BOOTING WHEN POWER ON THE SET ....................................................................................... 3-4
3. VFD IS NOT DISPLAYED WHEN POWER ON THE SET ..................................................................... 3-5
4. NO BOOTING IN CD/USB FUNCTION .................................................................................................. 3-6
5. NO OPERATION OF MD ..................................................................................................................... 3-11
6. NO SOUND .......................................................................................................................................... 3-16
7. AUDIO OUTPUT IS SMALL OR NO AUDIO OUTPUT ........................................................................ 3-23
8. NO POWER ON (STANDBY LED IS BLINKING) ................................................................................ 3-24
9. SPEAKER NO AUDIO .......................................................................................................................... 3-25
ELECTRICAL TROUBLESHOOTING GUIDE ................................................................................................ 3-26
1. POWER SUPPLY ON SMPS BOARD ................................................................................................. 3-26
2. SYSTEM PART .................................................................................................................................... 3-30
3. NO AUDIO PART ................................................................................................................................. 3-32
4. NO LIGHTING (WOOFER SPEAKER) ................................................................................................. 3-37
WAVEFORMS ................................................................................................................................................. 3-38
WIRING DIAGRAM ......................................................................................................................................... 3-43
BLOCK DIAGRAMS ........................................................................................................................................ 3-45
1. SMPS BLOCK DIAGRAM..................................................................................................................... 3-45
2. MAIN SYSTEM BLOCK DIAGRAM ...................................................................................................... 3-47
CIRCUIT DIAGRAMS ...................................................................................................................................... 3-49
1. SMPS #1 CIRCUIT DIAGRAM ............................................................................................................. 3-49
2. SMPS #2 CIRCUIT DIAGRAM ............................................................................................................. 3-51
3. MAIN - MICOM CIRCUIT DIAGRAM .................................................................................................... 3-53
4. MAIN - PWM CIRCUIT DIAGRAM ....................................................................................................... 3-55
5. MAIN - AMP CIRCUIT DIAGRAM ........................................................................................................ 3-57
6. MAIN - DSP CIRCUIT DIAGRAM ......................................................................................................... 3-59
7. MAIN - RF SERVO CIRCUIT DIAGRAM ............................................................................................. 3-61
8. MAIN - ADC CIRCUIT DIAGRAM ........................................................................................................ 3-63
9. VFD CIRCUIT DIAGRAM ..................................................................................................................... 3-65
10. MAIN VOLUME CIRCUIT DIAGRAM ................................................................................................... 3-67
11. MIC CIRCUIT DIAGRAM ...................................................................................................................... 3-69
12. MULTI JOG VOLUME CIRCUIT DIAGRAM ......................................................................................... 3-71
13. USB CIRCUIT DIAGRAM ..................................................................................................................... 3-73
14. AUX / TUNER / SPEAKER LIGHT JACK CIRCUIT DIAGRAM ........................................................... 3-75
15. SPEAKER LED_MAIN CIRCUIT DIAGRAM ........................................................................................ 3-77
16. SPEAKER LED CIRCUIT DIAGRAM ................................................................................................... 3-79
CIRCUIT VOLTAGE CHART .......................................................................................................................... 3-81
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-87
1. SMPS P.C.BOARD ............................................................................................................................... 3-87
2. MAIN P.C.BOARD ................................................................................................................................ 3-89
3. VFD P.C.BOARD .................................................................................................................................. 3-93
4. MAIN VOLUME P.C.BOARD ................................................................................................................ 3-95
5. MIC P.C.BOARD .................................................................................................................................. 3-95
6. JOG P.C.BOARD .................................................................................................................................. 3-97
7. USB P.C.BOARD .................................................................................................................................. 3-98
8. TUNER P.C.BOARD ............................................................................................................................. 3-98
9. SPEAKER LED_MAIN P.C.BOARD ..................................................................................................... 3-99
10. SPEAKER LED P.C.BOARD ................................................................................................................ 3-99
3-1

LG CM9730 Specifications

General

Type	-
Cassette deck	No
Product color	Black
Disc loading type	Tray
Optical disc player	Yes
Impedance	75 Ω
RMS rated power	2300 W
Number of speakers	2
Power source	AC
Input voltage	220-230 V
Input frequency	50 - 60 Hz
Power consumption (standby)	1 W
Power consumption (typical)	180 W
Playback disc formats	CD audio
Audio formats supported	MP3, WMA
FM band range	87.5 - 108 MHz
Supported radio bands	AM, FM, MW
Preset stations quantity	50
Display type	LCD
Speaker depth	500 mm
Speaker width	520 mm
Speaker height	720 mm
Apple docking compatibility	Not supported
USB 2.0 ports quantity	USB 2.0 ports have a data transmission speed of 480 Mbps, and are backwards compatible with USB 1.1 ports. You can connect all kinds of peripheral devices to them.

Weight and Dimensions

Main unit dimensions (WxDxH)	542 x 421 x 310 mm