![LG CM4330 Service Manual Download Page 32](http://html.mh-extra.com/html/lg/cm4330/cm4330_service-manual_213474032.webp)
3-13
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the USB FUNCTION, repair the set according to the fol-
lowing guide.
5-3. IN THE USB FUNCTION
5-3-1. Solution
Please check and replace IC801 on MAIN board & IC502 on USB board.
5-3-2. How to troubleshoot (Countermeasure)
1) Check +5VU to USB board.
If the USB LED are turned on, the voltage is okay, if so not, check +5.6 V to pin6 of CN502.
2) Check USB D± from MAIN board to USB board.
a. Check USB_DM/DP signals to IC801(pin117, 118).
b. Check USB± signals to CN502 (pin1, 2, 4, 5).
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” on item 5-2 is normal.
5-3-3. Service hint (Any picture / Remark)
kT GXM[GGjuXWY
kRGGGY M\GjuXWY
USB HUB
USB2512
USB1
BX8805
(128
PIN)
IC601
TAS5548
PWM
FL
·
FR
·
F/L
F/R
IC701
AMP IC
TAS5612LA
SW
IC702
AMP IC
TAS5612LA
150Wx2
200Wx1
SW
< Waveform of USB D± signal >
< USB function signal
fl
ow >
Summary of Contents for CM4330
Page 13: ...1 12 MEMO ...
Page 15: ...2 2 MEMO ...
Page 19: ...A60 4 SPEAKER SECTION 4 1 FRONT SPEAKER CMS4330F ...
Page 51: ...3 32 MEMO ...
Page 66: ...3 61 3 62 2 MAIN P C BOARD TOP VIEW BOTTOM VIEW ...
Page 67: ...3 63 3 64 3 FRONT P C BOARD TOP VIEW BOTTOM VIEW ...