Pioneer SC-27 Service Manual page 48

1
[3] NW (NetWork) Block Troubleshooting
• Assume that the LCRs are neither in poor connection nor damaged.
A
• Although diagnosis is assumed to be performed from Side A, the wiring numbers on Side B are also described in the flowchart.
• This shows failure analysis for the NW (Network) Block of the DIGITAL MAIN Assy.
• The confirmation of peripheral circuits means mainly a power supply of IC, a sync signal, a existence of the input/output signal,
a conduction check and the appearance check of the bridges.
Step 1: Power supply
CN1900 (Pins 1, 2)
Is the
No
voltage of around
B
13 V input
?
Yes
L1902
Is the
No
voltage of 5 V
output?
Yes
C
L1931
Is the
No
voltage of around
3.3 V output
?
Yes
D
IC601 (Pin 4)
Is the
No
voltage of around
3.3 V output
?
Yes
IC602
Is the
E
No
voltage of around
1.8 V output
?
Yes
IC603
Is the
No
voltage of around
3.3 V output
?
Yes
F
To Step 2
48
1
2
V+13_UN
Check the HDMI RECT Assy.
V+5_DDD
Check Q1900 and its periphery.
(Pins 1,2,5,6: around 9 V
Pin 3: around 6 V Square wave)
NG
Check IC1900 and its
peripheral circuits.
V+3R3_HHH
Check Q1930 and its periphery.
(Pin 1: around 7.5 V Square wave
Pins 5,6: around 16.5 V)
NG
Check IC1930 and its
peripheral circuits.
Check IC601 and its peripheral
circuits.
V+1R8_NW
Check IC602 and its peripheral
circuits.
V+3R3_NW
Check IC603 and its peripheral
circuits.
2
3
Step 2: X'tal
IC701 (Pin 203)
Is there
a 24.576 MHz
input?
Yes
IC501 (Pin 46)
Is there
a 25 MHz
input?
Yes
To Step 3
Step 3: RESET
R931 (side B)
Is the
voltage "H"
(around 3.3 V)
?
Yes
IC1300 (Pin 91)
Is the
voltage "H"
(around 3.3 V)
?
Yes
IC701 (Pin 190)
Is the
voltage "H"
(around 3.3 V)
?
Yes
To Step 4
SC-27
3
4
CLK24.576NW
No
Check IC9351 and its peripheral
circuits.
No
Check the X501 and IC501 and
its peripheral circuits.
XEMRST
Perform the Step 1 and 2 of the
No
"[2] HDMI & DVC Block
Troubleshooting."
XGARST
Perform the Step 1 and 2 of the
No
"[2] HDMI & DVC Block
Troubleshooting."
XNETRST
No
Is the voltage of IC1304-pin 6
"H"?
NG
Check IC1300 and its
peripheral circuits.
4