Sony XM-7557 Service manual
XM-7557
SERVICE MANUAL
SPECIFICATIONS
US Model
Canadian Model
AEP Model
UK Model
E Model
MICROFILM
STEREO POWER AMPLIFER
1
TABLE OF CONTENTS
1. SERVICE MODE ............................................................. 3
2. GENERAL .......................................................................... 4
3. DISASSEMBLY
3-1. Side Plate, Sub 1/Sub 2 and Filer Board...............................7
3-2. Amplifier/Power Board and LED Board .............................. 7
4. ELECTRICAL ADJUSTMENT .................................... 7
5. DIAGRAMS
5-1. Block Diagram – Amplifier Section – .................................. 8
5-2. Block Diagram – Power Section – ........................................ 9
5-3. Block Diagram – Sub 1/Sub 2 Section – ............................ 10
5-4. IC Block Diagrams ............................................................. 10
5-5. Printed Wiring Board –Filter/Sub 1/Sub 2 Section –..........11
5-6. Printed Wiring Board –Amplifier Section – ....................... 12
5-7. Schematic Diagram
–Amplifier(1/3)/Filter/Sub 1/Sub 2 Section –..................... 13
5-8. Schematic Diagram/Printed Wiring Board
–Amplifier (2/3)/LED/TR Section – ................................... 14
5-9. Printed Wiring Board –Power Section –............................. 15
5-10. Schematic Diagram
–Power/Amplifier (3/3)/TR/LED Section –....................... 17
Notes on chip component replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be
damaged by heat.
6. EXPLODED VIEWS
6-1. Plate and Cover Section ...................................................... 18
6-2. Board and Heat Sink ........................................................... 18
7. ELECTRICAL PARTS LIST ........................................ 19
2
SECTION 1
SERVICE NOTE
Clearing the Protector During Repairs
• OVER CURRENT : Detects overcurrent during output.
• OFF SET : Detects DC offset at the speaker terminal.
1. Clearing the OVER CURRENT protector
• When the position of the MODE switch (S801/power board)
is set to HI-CURRENT :
Cut the jumper wire JW230 of the amplifier board.
2. Clearing the OFF SET protector
• Cut the jumper wire JW307 of the amplifier board.
3. TEST TONE Function
1 Press the TEST TONE button (S710/SUB2 board) with the
power ON. The amplifier is normal if sound is produced from
the speaker.
2 If no sound
: Problem causer by incorrect connecttion of the power supply
system or sperker system.
: The signals input by the RCA cable before the amplifier system
are abnormal.
Adjustment Location
- SUB 2 BOARD - (Component side) - AMPLIFIER BOARD - (Component side)
S710
TEST
TONE
- POWER BOARD - (Component side)
S801
MODE
TP7
TP6
VR101
JW307
VR201
JW230
VR301
TP4TP5
VR401
TP2
TP3
TP1
VR501
VR502
3
SECTION 2
GENERAL
This section is extracted from
instruction manual.
4
5
6
)
SECTION 3
DISASSEMBLY
Note: Follow the disassembly procedure in the numerical order given.
3-1. SIDE PLATE,SUB 1/SUB 2 AND FILTER BO ARD
1
Three screws
(BTP3x8)
2
Three screws
(BTP3x8)
!ª
Screw (BTP3x8)
@º
Sub 2 board
@¡
Sub 1 board
@§
Fan motor block
@¢
Screw (BTP3x8)
@∞
TR board
0
Side plate (R)
8
Three screws
(BTP3x8)
@£
CNP708 (2P)
3-2. AMPLIFIER/POWER BOARD AND LED BOARD
!£
Sub heat sink
(Amplifier)
0
Screw (BTP3x8)
9
Four screws
(P3x10)
8
T wo screws
(P3x14)
!™
Three screws
!¢
Two insulating sheets
(AMP)
(P3x6)
!§
!¶
!∞
(P2x10)
LED board
LED holder
@™
CNP803 (3P)
2
Four screws
(P4x40)
T wo screws
!¡
Six screws
(P3x10)
9
Screw (BTP3x8)
!¡
Screw (M4)
3
(BVTP3x14)
!•
Screw (BTP3x12)
Six screws
4
Bottom plate
!§
Filter board
!∞
Screw (BTP3x8)
!¶
CNP710 (10P)
4
1
(BTP3x12)
3
T wo screws
(BTP3x8)
5
Three screws
(BTP3x8)
7
Side plate (L)
6
!¢
Auto fuse
(F901 to F904)
!™
Screw (M4)
!£
Cover
T wo Retainers
5
Two screws (BVTP3x10)
6
Power board
7
Amplifier board
Five screws
Screw (BTP3x8
SECTION 4
ELECTRICAL ADJUSTMENT
IDLING CURRENT ADJUSTMENT
• Perform adjustments in the HI-VOLT AGE mode.
1 Adjustment point
Semi-fixed resistors VR101, VR201, VR301, VR401, VR501,
VR502 of amplifier board
2 Precautions on adjustments
1. Set the RCA input terminal to open.
2. Apply a voltage of 14.4V between the +12V terminal, REMOTE
terminal, and GND terminal.
3. Rotate the above semi-fixed resistors completely in the counterclockwise direction while observing the component side.
4. Check that the voltage at the adjustment point becomes 0 mV in
step 2.
5. Fine adjustments may be required according to the characteristics of the MOS-FET used.
• When adjusting the idling current
Rotating the semi-fixed resistor in the clockwise direction:
Increases the idling current
Rotating the semi-fixed resistor in the counterclockwise direction:
Decreases the idling current
*Take note that rotating excessively in the clockwise direction
will increase the idling current suddenly.
3 Approximate adjustment values
Adjust as follows so that the following voltages become
1.2 to 0.3 mV around 0.7 mV .
FL channel :
V oltage between TP7 and TP6: Use VR101 of the amplifier board
FR channel :
V oltage between TP7 and TP5: Use VR201 of the amplifier board
RL channel :
V oltage between TP7 and TP4: Use VR301 of the amplifier board
RR channel :
V oltage between TP7 and TP3: Use VR401 of the amplifier board
SUBWOOFER Channels :
First, adjust so that the voltage between TP1 and TP2 becomes
1.2 to 0.3 mV around 0.7 mV using VR501 of the amplifier
board.
Next, adjust so that the voltage between TP1 and TP2 becomes
2.4 to 0.6 mV around 1.4 mV using VR502 of the amplifier
board.”
Connection :
Digital voltmeter
TP7
TP1
(SUB WOOFER)
TP6
(FL-CH)
TP5
(FR-CH)
TP4
(RL-CH)
TP3
(RR-CH)
TP2
(SUB WOOFER)
TP1
(SUB WOOFER)
TP7
TP6
VR101
Adjustment Location
– AMPLIFIER BOARD – (Component side)
JW307
VR201
JW230
VR301
TP4TP5
TP3
VR401
TP2
TP1
VR501
VR502
7
7
XM-7557
5-1. BLOCK DIAGRAM – AMPLIFIER SECTION –
SECTION 5
DIAGRAMS
INPUT
MONO-L
MONO-R
CNJ701
FL
FR
RL
RR
CNJ710
SUB 1
BOARD
CNB710
CNP805
POWER
BOARD
CNB805
LINE SWITCH
Q102
LOWBOOST
VR703
D708
D709
D710
D711
LOWBOOST
5
6
LOWBOOST
5
6
LOWBOOST
VR708
L-CH
PRE AMP
IC703
5 7 6 7
LEVEL
VR701
H.P.F
IC702
CNP702
2 2
CNJ702
H.P.F
IC709
5 7 6 7 6 7
FILTER
VR702
L.P.F
IC708
X10,X1
S701
FILTER
FILTER
VR702
L.P.F
IC707
FLAT
HPF
LPF
FILTER
S702
CNJ702
3 3
CNP702
FILTER BOARD
PRE AMP
IC704
5
R-CH
9
TO
7
8
6
2
3
B+
5
B-
4
8
TO
2
4
9
3
1
10
6
7
5
7 6 7
FAN CTL
Q702
POWER
DRIVE
Q704
THERMAL
DET
TH701
LEVEL
VR704
H.P.F
IC702
FAN DRIVER
Q701
CNP703
2
2
CNJ703
CNP803 CNB803
H.P.F
IC710
5 7 6 7 6 7
FILTER
VR705
POWER
CONTROL
Q703
L.P.F
IC711
X10,X1
S704
FILTER
FILTER
VR705
CNP708
B+
L.P.F
IC712
CNJ708
INVERTER
TR BOARD
INVERTER
Q705
Q706
HPF
FLAT
LPF
M
CNJ703
3 3
CNP703
FILTER
S705
FN801
DC FAN MOTOR
T701
IC701
7
B+
LEVEL SHIFT
Q101
B-
LINE SWITCH
IC706
7
LEVEL SHIFT
Q301
LINE SWITCH
Q103
Q302
LINE SWITCH
Q303
B+
B-
+42V
+14V
-14V
-42V
DIRECT
SW703
ON OFF
OFF
ON
DIFFERENTIAL
AMP
Q104-105
DIFFERENTIAL
AMP
Q106-107
DIRECT
SW706
DIFFERENTIAL
AMP
Q304-305
DIFFERENTIAL
AMP
Q306-307
DIFFERENTIAL
AMP
Q504-505
DIFFERENTIAL
AMP
Q505-506
DIFFERENTIAL
AMP
Q512-513
DIFFERENTIAL
AMP
Q514-515
POWER AMP
(VOLTAGE STAGE)
Q108
BIAS
VR101,Q110
POWER AMP
(VOLTAGE STAGE)
Q109
NFB OFF
POWER AMP
(VOLTAGE STAGE)
Q308
BIAS
VR301,Q310
POWER AMP
(VOLTAGE STAGE)
Q309
NFB OFF
POWER AMP
(VOLTAGE STAGE)
Q507
BIAS
VR501,Q509
POWER AMP
(VOLTAGE STAGE)
Q508
NFB OFF
POWER AMP
(VOLTAGE STAGE)
Q516
BIAS
VR502,Q518
POWER AMP
(VOLTAGE STAGE)
Q517
NFB OFF
RY701
RY702
RY703(1/2)
RY703(2/2)
OFFSET
SET
Q707-713
POWER AMP
(FINAL STAGE)
Q111-112
NFB ON
POWER AMP
(FINAL STAGE)
Q311-312
NFB ON
POWER AMP
(FINAL STAGE)
Q510-511
NFB ON
POWER AMP
(FINAL STAGE)
Q519-512
NFB ON
OVERLOAD
Q113-114
OVERLOAD
Q313-314
OVERLOAD
Q521-Q524
R-CH
R-CH
SPEAKER OUT
CN704
L
MONO-L
R
CN705
L
MONO-R
R
CN707
SUB WOOFER
SPEAKER OUT
AMPLIFIER BOARD
09
• Signal path
: Audio
8
8
5-2. BLOCK DIAGRAM – POWER SECTION –
XM-7557
AMPLIFIER
BOAD
CNP805
POWER BOARD
CNB805
OFFSET CONTROL
7
TO
8
9
2
5
6
10
4
3
Q809-810
MUTE CONTROL
D808,Q811
MODE
S801
HI-V
HI-C
THERMAL DETECTOR
(For H,S)
TH903
THERMAL DETECTOR
(For TRANS)
TH904
OFFSET LED
MUTE SWITCH
Q812
OVER CURRENT
CONTROL
Q807-808
OVER CURRENT
LED SWITCH
Q805
NFB
S802
OFFON
D908
OR
D909
OR
SET
Q804
MUTE ENABLER
THERMAL
CONTROL
Q918
IC813
4 1
3
Q803
SWITCH
D805
THERMAL
GR
B+
MODE
S801
D806
OR
2
HI-C
D907
THERMAL
SWITCH
Q917
THERMAL
LED SWITCH
MODE
S801
Q806
HI-V
D910
D911
THERMAL SWITCH
TH905,Q919
IC903
DC DET
2
3
1
4
12
14
1
2
15
16
3
REF-REG
DC-DC
CONVERTER
IC904
DRIVER
11
Q921
10
DRIVER
8
Q920
9
SWITCHING
CONTROL
Q922-923
INVERTER
Q924,926,928
INVERTER
Q925,927,929
T902
HI-VHI-C
CNP804
4
5
6
7
3
1
D912
D913
B+
+28V
TO
AMPLIFIER
BOARD
-28V
B-
LED BOARD
D801
HI-VOLTAGE
GG GR
CNB804
D802
HI-CURRENT
OVER CURRENT
Q801
SWITCH
D803
Q802
SWITCH
D804
OFFSET
GR
+12V
SUB-WOOFER
BATTERY
GND
4-CHANNEL
BATTERY
+12V
REMOTE
CN802
CNJ801
09
F903 (25A)
(25A)
F904
(25A)
F901
(25A)
F902
D901
SWITCH
Q901-902
SWITCH CTL
Q903
SWITCH
Q904
SWITCH
Q905
THERMAL
DET
TH901
D904
D903
2
1
DC DET
IC901
THERMAL SWITCH
TH902,Q906
12
REF-REG
14
3
4
1
2
15
16
3
DC-DC
CONVERTER
IC902
DRIVER
11
Q908
10
DRIVER
8
Q907
9
SWITCHING
CONTROL
Q909-910
INVERTER
Q911,913,915
INVERTER
Q912,914,916
T901
D905
D906
B+
+28V
TO
AMPLIFIER
BOARD
-28V
B-
9
9
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