Pioneer XW-NAC3-K Service Manual page 20

1
QQ
3 7 63 1515 0
A
A
12 IC21 (Pin 4) 1.8V Regulator IC output
Is the No
voltage 1.8 V?
Yes
B
The output of IC21 and GND may be
short-circuited. Check the path
between them.
IC701 (Pins 18,38,56,71,86,95,114,128,
13
144,174,189)
C
Is the No
voltage 1.8 V?
TE
L 13942296513
Yes
14 IC801(Pin 1) USB Power SW output
Is the No
voltage 5 V?
D
Yes
No
E
14 CN801(Pin 1) USB Bus power
www
Is the No
voltage 5 V?
Yes
F
Power supply is OK.
To Step 3
20
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Is pin 1
Yes
(CONT) of IC21
3.3 V?
No
Is pin 15 (POWER) of
CN901 High (3.3 V)?
Is IC21
No
abnormally
hot?
Yes Replace IC21.
NETWORK Media
processor IC
Check the patterns in the path
between IC21 and IC701.
Is pin 4
No
(CTL) of IC801
High (3.3 V)?
Yes
Replace IC801.
Is pin20
No
(CTL) of CN901
High?
Yes Check the
MAIN PCB Assy.
Check around the
Q801 and Q802.
Check the patterns in the path
between IC801 and CN801.
x ao
y
. i
2
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8
Step 3: Operation of Network Media processor IC
Note: Please confirm it with the USB memory connected
for the content.
IC701(Pins 203,204)
Does
the crystal
oscillate at
24.576 MHz?
Yes
IC861(Pins 46,47)
Does
the crystal
oscillate at
25.000 MHz?
Yes
IC701(Pin 81)
Q Q
3 6 7
Does
81 pin output the
oscillation signal
of 25 MHz?
No
DM850E doesn't operates correctly.
It seems that there are following problems.
• F/W is not written correctly in FLASH ROM.
• FLASH ROM (IC881) is NG.
• SDRAM (IC891) is NG.
Step 4 : Communication between DM850E and
System Ucom
The signal shown by following fig are communication
line of DM850E and System Ucom (IC1000).
Confirm the connection of the signals along these
routes.
fig. 1
CN901
XRST Pin 14
SPI CS Pin 19
SPI CLK Pin 13
SPI TX Pin 17
fig. 2
IC701
u163
SPI RX Pin 146
SPI REQ Pin 100
XW-NAC3-K
3
4
2 9 9 4
XIN/XOUT
Is
No No
XRST (Pin 190)
high?
Yes
XRST must be high during
operation. Check the patterns
in the path between pin 14 of
CN901 and IC911, check the
MAIN PCB Assy.
Check the parts and patterns
in the path. Replace X701. etc.
XIN/XOUT
No
Check the power supply voltage
of IC861 again.
PHYCLK
1 3 1 5 0 5 8 2 9
OK, DM850E operates correctly.
No
It can be judged whether DM850E
operates correctly though this
signal is not connected.
IC911 (5V→3V)
IC701
Pin 12 Pin 11 Pin 190
Pin 2 Pin 3 Pin 143
Pin 5 Pin 6 Pin 141
Pin 9 Pin 8 Pin 147
m
IC921 (NM) bypass
CN901
co
R925 Pin 16
R924 Pin 18
.
4
2 8
9 9
9 4 2 8 9 9