S-W1EX
44
1
2
3
4
1
2
3
4
C
D
F
A
B
E
7.3 AMP BLOCK TROUBLE SHOOTING
A
A
The repair flow of the AMP section
PowerON
A signal from CN481.
(Sound from the speakers)
The LED lights.
Control Assy
Input, D AMP Assy
Solder shorting?
Check other
symptoms.
SMPS Assy Voltage of IC32?
Accidental
failure mode
'+''-' of multi-meter is reverse.
30k
Ω
to 40k
Ω
All FETs are O.K.
1k to 10k
All FETs are O.K.
Replace IR2011S
(IC421, IC441)
0 to 1k
FET has been broken.
Cases other than
2
–
4
below.
Solder correction
Replace IC32.
Less than [ 10V ]
CrossOver 50Hz?
Turn to Bypass and try again.
Check the screws
of D AMP ASSY.
Check soldering of
IC421,441(
B
-
2
)
Level is low.
Level is low.
Waveform is not normal.
no
OK
no
no
no
output
After 4 seconds
no output
yes
yes
yes
yes
yes
Go to
SMPS part
1
2
3
4
The speaker relay
is on.
The 8-pin IC is
hot.
Replace the hot IC, since it is no
longer serviceable.
Check the resistance between G and S of the FETs (Q421, 431, 441, and 451) with the multimeter.
"+" is assigned to G and "-" is assigned to S for the multimeter.
Multi-meter : ADVANTEST TR6847 or equivalent
FET : IRFB23N15D
Check soldering at IR2011S
(IC421, IC441)
Replace IR2011S located on
the same side as the FET
with low resistance.
Everything is all right, except for the waveform
(resistance of R471 and 472 is 10 ohms or more).
Replace R471 and R472 with new ones.
Everything is all right, except for the relay
not being turned on.
Replace Q506 and Q507 with new ones.
Although the VOL is minimum, there is
output from CN481.
Solder shorting of VR3141 of the
CONTROL Assy.
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