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 & IC505 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 pin4 of CN501.
2) Check USB D± from MAIN board to USB board.
a. Check USB_DN/DP signals to IC801(pin116, 117).
b. Check USB± signals from IC504 to CN501 (pin2, 3).
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 GZ Gju[WX
kRGGGY Gju[WX
USB
IC801
MLC9800
IC602
PS9850
PWM
AMP IC
TAS5612
DAC_BCK
DAC_LRCK
DAC_DATA
DAC_MCLK
USB CON
REG IC
D+/-
P-CTRL
< Waveform of USB D± signal >
< USB function signal
fl
ow >
Summary of Contents for RAS376BF
Page 11: ...1 10 MEMO ...
Page 13: ...2 2 MEMO ...
Page 17: ...2 8 A60 4 SPEAKER SECTION 4 1 FRONT SPEAKER RAS376BF ...
Page 18: ...2 9 A90 4 2 PASSIVE SUBWOOFER RAS376BW ...
Page 19: ...2 10 MEMO ...
Page 51: ...3 32 MEMO ...
Page 63: ...3 55 3 56 PRINTED CIRCUIT BOARD DIAGRAMS 1 MAIN P C BOARD TOP VIEW Rev 2 2 ...
Page 64: ...3 57 3 58 MAIN P C BOARD BOTTOM VIEW EAX63554401 Rev 2 2 ...
Page 66: ...3 61 3 62 4 USB P C BOARD MEMO ...
Page 67: ...3 63 3 64 MEMO MEMO ...