Service manual

38
VSX-918V-K
1
2 3 4
A
B
C
D
E
F
1
2 3 4
Ye s
Ye s
Is IC402
abnormally
hot?
Replace IC402.
The output and GND may be
short-circuited. Check the path
between them.
No
Is
the voltage
1.8 V ?
No
Ye s
Check the parts and
patterns in the path.
IC331 (pin 14)
5 V to 3 V Converter
11
Is
the voltage
3.3 V ?
No
IC402 (pin 5)
1.8 V Regulator output
13
Ye s
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 ?
No
Ye s
Check the parts and
patterns in the path.
IC401 (pins 7, 24, 41, 71, 77, 87, 109, 119)
USB Media control IC
14
Is
the voltage
1.8 V ?
No
A
Check the
MAIN Assy.
Replace IC471.
Ye s
Ye s
Ye s
Is pin 4 [USB
CTL] of IC471
high?
Is
the voltage
5 V ?
No
Ye s
Is pin 20
(CTL) of CN3*,
CN7** high?
No No
Check the parts and
patterns in the path.
CN401 (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
No
IC471 (pin 1)
USB Power SW output
15
* VSX-918V (AWX8977)
** VSX-818V (AWX9164)