39
VSX-918V-K
5
6
7
8
5
6
7
8
A
B
C
D
E
F
Step 3: Operation of USB Media control IC
Does the
crystal oscillator
at 12 MHz
?
Note:
Please confirm it with the USB memory*1 connected for the content.
*1 iPod : This system is compatible with the audio of the following
portable device in Jan. 200
8
.
5G iPod, iPod nano, iPod nano 2G, iPod nano 3G,
iPod classic, iPod touch
Check C
N
3*, C
N
7**
pin 16. [USB XRST]
USBDAO and USBDAI should be
high during operation.
Check the pattern in the path.
Check the MAI
N
Assy.
Check the parts and patterns in the path.
Replace X402, etc.
N
o
Yes
Yes
Is XRST
high?
N
o
Yes
N
o
IC401 (pins 74,75)
USBDAI, USBDAO (Refer to Fig. 1)
IC401 (pin 44) -> IC461 (pin 3
8
)
XI
N
/XOUT
* XRST must be high during operation.
Check the MAI
N
Assy.
Fig. 1
Do
USBDAO and USBDAI
Communicate with
System CPU?
IC401
IC351 (3 V -> 5 V)
USBDAO
pin 95
pin 9
pin 11
CN3*, CN7**
pin 19
IC401
IC331 (5 V -> 3 V)
USBDAI
pin 96
pin
8
pins 9, 10
CN3*, CN7**
pin 1
8
IC401
R455 / R456
XRST
pin 77
CN3*, CN7**
pin 16
Operation of IC401 is OK.
To STEP 4
Operation of IC401 is OK.
To STEP 4
DATA and ADDRESS lines
between SDRAM (IC462),
FLASH ROM (IC461) and IC401
are may not be connected.
D+ and D- should have
waveform during normal
condition.
Check the pattern in the path.
Check the MAI
N
Assy.
Replace IC461, IC462. etc.
Are
there the waveforms
like figure?
After
turning the power
on and several seconds
later, does SDCLK change
12 MHz to
8
0 MHz?
Yes
Yes
N
o
N
o
C
N
401 (pins 2,3)
D+/D-
Initial communication [SDCLK]
Fig. D+
X: 1
μ
S/div, Y: 2
V
/div
X: 1
μ
S/div, Y: 2
V
/div
Fig. D-
*
V
SX-91
8V
(A
W
X
8
977)
**
V
SX-
8
1
8V
(A
W
X9164)
