3-23
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 IC501, IC504 on MAIN board & IC3U01 on USB board.
5-3-2. How to troubleshoot (Countermeasure)
1) Check +5VU to USB board.
If the USB LEDs are turned on, the voltage is okay, if so not, check +5.6 V to Pin8 of CN602.
2) Check USB D± from main board to USB board.
a. Check USB_HUB_DN/DP signals to IC501(Pin116, 117)
b. Check USB1/2_DN/DP signals from IC504 to CN602 (Pin10, 11, 13, & 14)
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 G XWGGju]WY
kRGGGXXGGju]WY
USB
Board
{T
IC501
MLC9800
IC602
PS9850
PWM
IC801
FS502B
BEAT BOX
AMP IC
TAS5631
DAC_BCK
DAC_LRCK
IC504
USB2512B
DAC_DATA DAC_MC LK
ADC_DATADAC_MC LK
USB_D
BEAT_DATA
USB
< Waveform of USB D± signal >
< USB function signal fl ow >
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