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3-26
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the USB FUNCTION, repair the set according to the fol-
lowing guide.
6-2-2. IN THE USB FUNCTION
6-2-2-1. Solution
Please check and replace IC501, IC504 on MAIN board & IC3U01 on USB board.
6-2-2-2. How to troubleshoot (Countermeasure)
1) Check +5VU to USB board.
If +5.6VA to pin1 or pin2 of CN3U1.
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 IC504 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” Item 6-3 is normal.
6-2-2-3. Service hint (Any picture / Remark)
kT GG\GGju\WY
kRGGG[GGju\WY
USB
USB
Board
{T
{T
IC501
MLC3700
IC602
PS9854
PWM
IC801
FS503B
BEAT BOX
AMP IC
TAS5631
DAC_BCK
DAC_LRCK
IC504
USB2512A
DAC_DATA
DAC_MCLK
ADC_DATA
DAC_MCLK
USB_D
BEAT_DATA
< Waveform of USB D± signal >
< USB function signal
fl
ow >
Содержание CM7420
Страница 13: ...1 12 MEMO ...
Страница 15: ...2 2 MEMO ...
Страница 19: ...A60 4 SPEAKER SECTION FRONT SPEAKER CMS7520F ...
Страница 82: ...3 79 3 80 PRINTED CIRCUIT BOARD DIAGRAMS 1 SMPS P C BOARD TOP VIEW ...
Страница 84: ...3 83 3 84 2 MAIN P C BOARD TOP VIEW ...
Страница 85: ...3 85 3 86 MAIN P C BOARD BOTTOM VIEW ...
Страница 86: ...3 87 3 88 3 FRONT_VFD P C BOARD TOP VIEW BOTTOM VIEW ...
Страница 87: ...3 89 3 90 4 FRONT_MIC PORTABLE P C BOARD TOP VIEW BOTTOM VIEW ...
Страница 88: ...3 91 3 92 5 FRONT_VOLUME P C BOARD TOP VIEW ...
Страница 89: ...3 93 3 94 FRONT_VOLUME P C BOARD BOTTOM VIEW ...