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3-17

ONE POINT REPAIR GUIDE

NO SOUND

There is no sound output in the USB FUNCTION, repair the set according to the fol-

lowing guide.

6-2. IN THE USB FUNCTION

6-2-1. Solution

Please check and replace IC501, IC504 on MAIN board & IC3U01 on USB board.

6-2-2. How to troubleshoot (Countermeasure)

1) Check +5VU to USB board.

 If +5.6 VA to pin2 of IC3U01(LDO) doesn’t come out, check pin4, 5 of CN502.

 If +5.6 VA is normal & +5VU of IC3U01 pin3 doesn’t come out, then replace IC3U01.

2) Check USB D± from main board to USB board.

a. Check USB_HUB_DN/DP signals to IC501(pin16, 18)

b. Check USB1/2_DN/DP signals from IC501 to CN502 (pin1, 2, 9 & 10)

 If there is any trouble, check the power for each IC. The power is normal but, if the signal waveform to

the IC is distorted or no signal, replace it with a new one.

3) Check if “Digital audio AMP block”.

6-2-3. Service hint (Any picture / Remark)

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jvkljGW

jvkljGX

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wz`_\[

w~tGpj

jz\Z[]

hkjGpj

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hkjGpj

mGtpj

hkjkh{h

tpjkp

khjkh{h

IR AMP

IRS2092+IRF6775

USB

Board

IC504

USB2512B

USB1_D+/-

USB2_D+/-

USB_D+/-

< Waveform of USB D± signal >

USB D+ / D- (CN502 Pin1, 2 & 9, 10)

< USB function signal ﬂ ow >

Other manuals for LG CM9730

Owner's Manual34 pages

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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.