Pioneer VSX-918V-S Service Manual page 39

5
QQ
3 7 63 1515 0
Step 3: Operation of USB Media control IC
IC401 (pins 74,75)
Does the
crystal oscillator
at 12 MHz
?
Yes
USBDAI, USBDAO (Refer to Fig. 1)
Do
USBDAO and USBDAI
Communicate with
System CPU?
Yes
CN401 (pins 2,3)
TE
L 13942296513
Are
there the waveforms
like figure?
No
IC401 (pin 44) -> IC461 (pin 38)
After
turning the power
on and several seconds
later, does SDCLK change
12 MHz to 80 MHz?
Yes
Operation of IC401 is OK.
To STEP 4
www
.
5
http://www.xiaoyu163.com
6
XIN/XOUT
No No
Is XRST
high?
* XRST must be high during operation.
Yes
Check the MAIN Assy.
Check the parts and patterns in the path.
Replace X402, etc.
No
USBDAO and USBDAI should be
high during operation.
Check the pattern in the path.
Check the MAIN Assy.
D+ and D- should have
D+/D-
waveform during normal
condition.
Check the pattern in the path.
Check the MAIN Assy.
Replace IC461, IC462. etc.
Yes
Operation of IC401 is OK.
To STEP 4
Initial communication [SDCLK]
DATA and ADDRESS lines
No
between SDRAM (IC462),
FLASH ROM (IC461) and IC401
are may not be connected.
x ao u163
y
i
6
http://www.xiaoyu163.com
7
2 9
8
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. 2008.
5G iPod, iPod nano, iPod nano 2G, iPod nano 3G,
iPod classic, iPod touch
Check CN3*, CN7**
pin 16. [USB XRST]
Fig. 1
IC401
XRST pin 77
IC401
USBDAI pin 96
IC401
USBDAO pin 95
Fig. D+
Q Q
3 6 7 1 3 1 5
X: 1 μS/div, Y: 2 V/div
co
.
VSX-918V-K
7
8
9 4 2 8
* VSX-918V (AWX8977)
** VSX-818V (AWX9164)
R455 / R456
IC331 (5 V -> 3 V)
pin 8 pins 9, 10
IC351 (3 V -> 5 V)
pin 9 pin 11
Fig. D-
0 5 8 2 9 9 4 2 8
X: 1 μS/div, Y: 2 V/div
m
8
9 9
A
B
CN3*, CN7**
pin 16
CN3*, CN7**
pin 18
CN3*, CN7**
pin 19
C
9 9
D
E
F
39