VSX-LX50
67
5
6
7
8
5
6
7
8
C
D
F
A
B
E
Step 3:
O
peration of
U
SB Media control IC
Does the
crystal oscillator
at 12 MHz
?
Check the
MOTHER Assy.
Note:
Please confirm it with the USB memory connected for the content.
IC701 (pins 7,24,40,58,73,74,91,110,124)
USB Media control IC
10
Replace IC771.
Yes
Yes
Yes
Is pin 4
(CTL) of IC771
high?
Is
the voltage
5 V ?
No
Yes
Is
the voltage
1.8 V ?
Yes
Is pin 1
(CTL) of CN702
high?
No
No
Check the parts and
patterns in the path.
Check the parts and
patterns in the path.
No
CN701 (pin 1)
USB Bus power
12
Is
the voltage
5 V ?
Check the parts and
patterns in the path.
Power supply is OK.
To STEP 3
No
XRST must be high during operation.
Check the MOTHER Assy.
USB-T
x
and USB-R
x
should be
high during operation.
Check the pattern in the path.
Check the MOTHER Assy.
Replace IC762, IC701, IC761.
Check the parts and patterns in the path.
Replace X702, etc.
No
Fig. 1
IC771 (pin 1)
USB Power SW output
11
Yes
Yes
Is XRST
high?
No
Yes
No
IC701 (pins 74,75)
USB-T
x
/USB-R
x
(Refer to Fig. 1 and 2)
XIN/XOUT
A
B
IC701
CN702
XRST
pin 77
R951
pin 5
USB-R
x
pin 96
R955
pin 10
Fig. 2
IC701
IC951
(
3 V
→
5 V
)
CN702
USB-T
x
pin 95
pin 2
pin 4
pin 11
Does
USB-T
x
and USB-R
x
Communicate with
System CPU?