38
VSX-918V-K
1
2
3
4
A
B
C
D
E
F
1
2
3
4
Yes
Yes
Is IC402
abnormally
hot?
Replace IC402.
The output and G
N
D may be
short-circuited. Check the path
between them.
N
o
Is
the voltage
1.
8
V
?
N
o
Yes
Check the parts and
patterns in the path.
IC331 (pin 14)
5
V
to 3
V
Converter
11
Is
the voltage
3.3
V
?
N
o
IC402 (pin 5)
1.
8
V
Regulator output
13
Yes
Check the parts and
patterns in the path.
IC401 (pins 16, 33, 64, 76, 112)
USB Media control IC
12
Is
the voltage
3.3
V
?
N
o
Yes
Check the parts and
patterns in the path.
IC401 (pins 7, 24, 41, 71, 77,
8
7, 109, 119)
USB Media control IC
14
Is
the voltage
1.
8
V
?
N
o
A
Check the
MAI
N
Assy.
Replace IC471.
Yes
Yes
Yes
Is pin 4 [USB
CTL] of IC471
high?
Is
the voltage
5
V
?
N
o
Yes
Is pin 20
(CTL) of C
N
3*,
C
N
7** high?
N
o
N
o
Check the parts and
patterns in the path.
C
N
401 (pin 1)
USB Bus power
16
Is
the voltage
5
V
?
Check the parts and
patterns in the path.
Power supply is OK.
To STEP 3
N
o
IC471 (pin 1)
USB Power S
W
output
15
*
V
SX-91
8V
(A
W
X
8
977)
**
V
SX-
8
1
8V
(A
W
X9164)
