Pioneer VSX-LX70 Service Manual page 68

1
A
A
IC701 (pins 7,24,40,58,73,74,91,110,124)
10
Is
No
the voltage
1.8 V ?
Yes
IC771 (pin 1)
11 USB Power SW output
B
Is
No
the voltage
5 V ?
Yes
CN701 (pin 1)
12 USB Bus power
C
Is
No
the voltage
5 V ?
Yes
Power supply is OK.
To STEP 3
Step 3: Operation of USB Media control IC
D
IC701 (pins 74,75)
XIN/XOUT
Does the
crystal oscillator
at 12 MHz
?
Yes
E
USB-Tx/USB-Rx (Refer to Fig. 1 and 2)
Does
USB-Tx and USB-Rx
Communicate with
System CPU?
Yes
B
F
68
1
2
USB Media control IC
Check the parts and
patterns in the path.
Is pin 4
No
(CTL) of IC771 (CTL) of CN702
high?
Yes
Check the parts and
Replace IC771.
patterns in the path.
Check the parts and
patterns in the path.
No No
Is XRST
high?
Yes
Check the parts and patterns in the path.
Replace X702, etc.
No
USB-Tx and USB-Rx should be
high during operation.
Check the pattern in the path.
Check the MOTHER Assy.
Replace IC762, IC701, IC761.
2
3
Is pin 1
No
Check the
MOTHER Assy.
high?
Yes
Note: Please confirm it with the USB memory connected for the content.
XRST must be high during operation.
Check the MOTHER Assy.
Fig. 1
IC701
XRST pin 77
USB-Rx pin 96
Fig. 2
IC701
USB-Tx pin 95
VSX-LX70
3
4
CN702
R951 pin 5
R955 pin 10
IC951 (3 V → 5 V)
CN702
pin 2 pin 4 pin 11
4