3-16
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 IC352(LDO) doesn’t come out, check pin2, 3 of CN351.
If +5.6 VA is normal & +5VU of IC352 pin3 doesn’t come out, then replace IC352.
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 (pin5, 6, 8 & 9)
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)
< Waveform of USB D± signal >
USB D+ / D- (CN502 Pin5, 6 & 8, 9)
< USB function signal fl ow >
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