28
VSX-LX52
1
2
3
4
A
B
C
D
E
F
1
2
3
4
5. DIAGNOSIS
5.1 DIAGNOSIS FLOWCHART
Step 1: MUTE pin
Replace IC301.
Replace D5
8
2.
To Step 2
To Step 3
Step 0: Preliminary confirmation
Confirm the following items before checking
Do
screws of
earth terminal (K
N
4
8
1)
securely tighten
?
Tighten screws securely.
Note:
If this section is not fixed,
the G
N
D for DSP module
may lifted from the chassis
and cause instable potential
and lead to product failures.
N
o
Yes
To Step 1
IC301 (Pin
8
4) (or R324)
Is the
voltage of output
signal 0
V
?
N
o
N
o
Yes
Replace IC5
8
2 (side B).
N
G
Replace IC5
8
1.
N
G
DSP1MUTE
V
+5_DDD1
Check the Q1900 and
its periphery block.
Check the C121, C114,
C509 and C459.
Check the C333.
IC5
8
1 (Pin 1)
Is the
voltage of around
5
V
input?
Is the
voltage of 3.3
V
output?
N
o
Yes
(to chassis)
V
+3R3_D
(to chassis)
D5
8
2 (Cathode)
Is the
voltage of around
2.7
V
output
?
N
o
Yes
IC5
8
1 (Pin 3)
N
o
Yes
Is the
voltage of 1
V
input?
C333 (+ side)
N
o
Yes
V
+1_DSPF
N
G
Check the C506 and C527
Check the TRA
N
S 3 Assy.
Is the
voltage of 5
V
input?
C506 (+ side)
N
o
Yes
V
+5_DAC
N
G
Check the C606, C656, C706
and C756.
Replace Q551 (side B).
Is the
voltage of 5
V
input?
C606 (+ side)
N
o
Yes
V
+5_DACA
N
G
Check the C552.
Replace R552.
Is the
voltage of around
5
V
input?
C552 (+ side)
N
o
Yes
V
+5_DACD
Step 2: Power supply
Simplified diagnosis
Errors in the Audio Block of the DIGITAL MAI
N
Assy (those simply and roughly predictable by machine operation only)
• Sound abnormality in Delay
If sound abnormality does not occur in the Delay OFF state but occurs in the Delay O
N
state, it is most likely that a failure
has occurred in SDRAM (IC251) or LATCH (IC2
8
1, IC291) in the DSP Block.
•
N
o sound at analog signal input
If sound abnormality does not occur with digital signal input (COAX, OPT, etc.) but occurs only with analog signal input,
it is most likely that a failure has occurred in the AD converter (IC501).
•
N
o sound with the PQLS O
N
(normal sound with the PQLS OFF)
If no sound is output during CD playback with the PQLS O
N
, it is most likely that a failure has occurred in the crystal
oscillator (X361). (Diagnosis point A)
<If no sound is output in Multi-Channel-Signal Playback or Surround mode with the COAX, OPT, USB, and HDMI inputs>
• Assume that the LCRs are neither in poor connection nor damaged.
• Assume that diagnosis is performed from Side A.
• This shows failure analysis for the DSP Block of the DIGITAL MAI
N
Assy.
DSP Troubleshooting
Check the DSP and down
stream block. Go to step 6.
1
4
5
6
7
8
2
3
1
• The parts marked like in the following chart are located in "Check Points of the DIGITAL MAI
N
Assy."
