Alto AMX-120 Service Manual
Service Manual
Model: AMX-120
www.altoproaudio.com
Versi on: .2
CONTENTS
1. Specification
2. Block Diagram
3. Schematic Diagram
4. Printed Circuit Board
5. Wiring Diagram
6. Test Procedure
7. Electrical Parts List
8. Exploded Views & Mechanical Parts List
9. Notes
8. TECHNICAL SPECIFICATION
Mono input channels
Microphone input
Frequency response
Distortion (THD & N)
Gain range 0dB to 44dB (MIC)
SNR (Signal to Noise Ratio)
Line input
Frequency response
Distortion (THD & N)
Sensitivity range
Stereo input channels
Line input
Frequency response
Distortion (THD & N)
Impedances
Microphone input
Channel Insert return
All other inputs
Tape out
All other output
Equalization
Hi shelving
Mid bell
Low shelving
Low Cut filter
Main Mix Section
Noise (Bus noise) Fader 0 dB, channels muted: 100dBr (ref.:+4dBu)
Max output
AUX Sends max out
Power supply (AC/AC Adaptor)
Main voltage
Power Consumption
Physical
Dimension (W D H) 208mm 275.5mm 35/43mm
Net weight
Shipping weight 2.3Kg (5.11lb)
electronically balanced, discrete input configuration
10Hz to 55kHz, + 3dB
0.005% at +4dBu, 1kHz
115dB
electronically balanced
10Hz to 55kHz, + 3dB
0.005% at +4dBu, 1kHz
+15dBu to 30dBu
Unbalanced
10Hz to 55kHz, 3dB
+
0.005% at +4dBu, 1kHz
1.4kOhm
2.5kOhm
10kOhm or greater
1kOhm
120Ohm
+ 15dB @12kHz
+ 12dB @2.5kHz
+ 15dB @80Hz
75Hz, 18dB/oct.
Fader 0dB, all input channels assigned and set to
UNITY gain: 90dBr (ref.:+4dBu)
+22dBu unbalanced, 1/4" jacks
+22dBu
USA/Canada 100 120V~, 60Hz
Europe 210 240V~, 50Hz
U.K./Australia 240V~, 50Hz
11 watts
(6.06" 7.81" 1.01"/1.30")
1.65Kg (3.65lb)
17
D
C
B
A
VER031216
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8
LEFT
RIGHT
PHONES
LEFT
RIGHT
TAPE OUT
MAIN OUT
AUX SEND1
TRS
AUX SEND
7654321
TRS
MAIN MIX LEFT
TRS
MA N MIX RIGHT
2-TRACK
TRS
PHONES OUTPUT
TAPE IN
TRS
CONTROL ROOM OUTPUT
TRS
RevisionModel No:
AMX-120 BLOCK DIAGRAM
ALTO MIXING CONSOLE
A2(C)
Titel
Size
Drawn By:
Sheet
19-Dec-2003
AMX-120MAP.Sch
File:
Date:
EFX SEND
AUX-1
RIGHT-BUS
LEFT-BUS
LEFT-BUS
PAN
LEVEL
AUX-1
RIGHT-BUS
LEVEL
MA N MIX
EFX SEND
AUX1
POST
1 2
LEVEL
2TK IN
2
2
1
3
1
2TK TO MIX
LEFT-BUS
AUX-1
RIGHT-BUS
LEFT-BUS
RIGHT-BUS
3RIGHT-BUS
LEFT-BUS
BALANCE
PRE
1 2
2TK TO CTRL ROOM
POST
1
2
AUX1
1 2
3
PRE
1
3
2
CONTROL ROOM
AUX-1
1 2
LEFT METER
& PHONES
RIGHT METER
AUX-1
EFX SEND
RIGHT-BUS
LEFT-BUS
12K2.5K80
+/-15db
+48V
+
213
3-BAND EQ
-
MIC IN
LINE IN
LO MID HI
GAIN
POWER
PHANTOM
MONO INPUT CHANNELS ( 1-2 )
SG/OL
LEVEL
-
+
T
RSRN
TN
3c5e1a4d2b
MIC GAIN:0~60dB
LINE IN TRIM:+15dB~-45dB
STEREO INPUT CHANNELS (3-10)
LEFT(MONO)
-
RSRN
3c5e1a4d2b
TN
SG/OL
+
T
RIGHT
1 2 3 4 5 6 78
D
C
B
A
D
8
C
B
A
VER031229
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KEVIN LIN.
RevisionModel No:
Drawn By:
Sheet
LEFT-BUS
AMX-120 (1/4)
5K11
R287
VR10
W50K
PAN
4K7
R77
7654321
22P
C180
R256
3K9
C89
47u/25V
22P
C179
C163
18n(M)
VR4
B50K
C131
18n(M)
EQ HI
C17
47u/25
1
U5A
NJM4580M
3
2
R27
5K11
R25
10K0
1
U1A
NJM4580M
3
R19
11K0
C15
22u/35V
LO CUT
R5
2
VR1
R23
C21
C90
R270
36K
VR9
LEVEL
C88
1M
R220
C87
C171
R212
12KHZ
SW3A
20K 1%
R28
C29
R3
O10K
3K6
47u/63V
R78
47u/25V
1
2
W50K
47u/25V
6
47u/25V
12n(M)
1K1
PS-22E85L
5K11
22P
5K11
R15
C3
470P
4K7
3
7
C28
6K81 1/4W
RIGHT-BUS
U9A
5
R137
C30
C4
J1
NJM4580M
1K3
C200
22P
22P
47P
PH PWR
R286
R236
U9B
R197
VR5
R196
0.22u/50V
R73
5K11
POST
22K
NJM4580M
910R
B50K
910R
C27
22P
27R 1%
AUX-1
R269
C199
R16
(PRE)
MID
AUX-POST
R152
C195
2.5K
SW3B
6K8
0.22u/50V
R4
C23
6K81 1/4W
VR11
W50K
+VCC
R264
1K5
6K8
2.2u/50V
C155
12n(M)
PS-22E85L
C208
1K3
R267
5K11
7
6
1000u/10V
C22
47u/63V
R284
R151
VR3
R150
47u/25V
5
5K11
6K8
B50K
6K8
6
R26
U1B
PEAK
R248
LO
7
5
C198
10K0
NJM4580M
C16
22u/35V
4K7
0.22u/50V
LD1
TR2
R228
C140
C139
80HZ
RED
BR
47K
33n(M)
33n(M)
20K
R273
U5B
R263
R24
R20
TR1
R47
NJM4580M
62K
3K6
11K0
R69
BR
10K0
51K1
C18
R21
22u/35V
PGND
11K0
C24
R33
R31
U2A
47u/63V
R291
R79
PAN
C96
C164
18n(M)
VR7
B50K
C132
18n(M)
C20
47u/25
U25A
NJM4580M
3
5K11
10K0
1
NJM4580M
3
LEFT-BUS
5K11
4K7
C183
R257
47u/25V
C181
1
2
VR2
R29
22P
3K9
22P
2
VR13
EQ HI
C33
O10K
3K6
W50K
R271
LEVEL
R221
12KHZ
LO CUT
R12
22P
R10
5K11
R17
C10
C98
47u/25V
36K
2
VR12
W50K
C95
1M
C94
47u/25V
C172
12n(M)
1K1
R213
SW4A
20K 1%
R34
6K81 1/4W
470P
R80
1
3
47u/25V
7
6
(SOLTON 1K2)用
PS-22E85L
5K11
22P
C32
C11
47P
4K7
PH PWR
RIGHT-BUS
U10A
5
R139
C34
C31
R74
5K11
R290
J2
NJM4580M
R237
U10B
R199
VR8
1K3
R198
C207
0.22u/50V
22P
22P
27R 1%
R18
POST
22K
NJM4580M
910R
B50K
910R
R11
C26
6K81 1/4W
AUX-1
(PRE)
MID
R272
C202
5K11
6
1000u/10V
C25
AUX-POST
R265
R156
C196
2.5K
SW4B
6K8
0.22u/50V
7
47u/63V
VR14
W50K
+VCC
1K5
6K8
2.2u/50V
C156
12n(M)
PS-22E85L
C209
1K3
R268
R32
10K0
U2B
5
C19
5K11
R288
R155
VR6
R154
47u/25V
6
NJM4580M
22u/35V
6K8
B50K
6K8
7
PEAK
4K7
R249
LO
5
C201
R22
C142
C141
80HZ
0.22u/50V
R30
R386
LD2
TR4
R229
33n(M)
R274
3K6
11K0
51K1
RED
BR
47K
33n(M)
20K
U25B
NJM4580M
R266
62K
TR3
R55
BR
10K0
C53
C9
C110
R141
47u/25V
22P
10K0
R6
22P
3K9
R153
R302
C126
36K
VR19A
LEVEL
1K2
100P
R169
R112
C56
2
W50K
C51
R39
LEFT-BUS
12K
4K7
47u/25V
1
22K
R125
47u/25V
10K0
2
R7
3
1
10K0
3
BAL
R96
U4A
U3A
VR20
W50K
10K0
NJM4580M
R187
NJM4580M
R14
SW5A
C6
C127
R40
20K
10K0
PS-22E85L
22P
100P
10K0
+4/-10 DB
C54
C12
R113
C111
R142
47u/25V
22P
10K0
R9
22P
3K9
4K7
RIGHT-BUS
R95
R41
R170
10K0
R149
LEVEL
10K0
R303
C128
12K
36K
6
W50K
VR19B
R126
C52
R36
1K2
100P
7
22K
47u/25V
10K0
6
R13
5
7
10K0
5
C55
J3
47u/25V
U4B
U3B
POST
NJM4580M
20K
R186
NJM4580M
10K0
R35
SW5B
C8
C129
AUX-1
(PRE)
PS-22E85L
+4/-10 DB
22P
100P
AMX-120
INPUT STAGE ( CH1-CH4 )
3-Jan-2004
AMX-120.Sch
A2
Titel
Size
File:
Date:
C211
C210
100n
84
C301
100n
84
C299
100n
84
C291
100n
84
C289
100n
84
C287
100n
84
C205
100n
84
C203
100n
84
+VCC
AMX-120
AMX-120.S03
U25C
U10C
U9C
U5C
U4C
U3C
U2C
U1C
VR15
W50K
AUX-POST
8K2
R168
R114
4K7
47K
R104
LD3
TR6
PEAK
RED
BR
TR5
R105
PGND
BR
UNINSERTED
47K
R135
R91
C106
+VCC
1K5
6K8
2.2u/50V
100n
C302
100n
C300
100n
C292
100n
C290
100n
C288
100n
100n
C206
C204
100n
-VCC
C1
470P
R2
4R7
213
4
MIC 1
X1
D
R1
SMC-6.02
4R7
3c5e1a4d2b
LINE IN1
R68
C2
470P
51K1
C5
X3
JY-6351G-02-250
LINE IN GAIN=+10~-40dB
MIC GAIN=-10~-60dB
470P
4R7
R38
213
4
MIC 2
X2
R37
SMC-6.02
4R7
3c5e1a4d2b
LINE IN2
C
R8
470P
JY-6351G-02-250
51K1
T
RSRN
TN
3c5e1a4d2b
LINE IN 3/4
AMX-120
AMX-120.S02
T
RSRN
TN
3c5e1a4d2b
X5
JY-6351G-02-250
LEFT(MONO)
B
X6
JY-6351G-02-250
AMX-120
AMX-120.S01
RIGHT
1 2 3 4 5 6 78
A
C7
X4
D
8
C
B
A
VER021229
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RevisionModel No:
Drawn By:
Sheet
AMX-120
INPUT STAGE ( CH5-CH8)
AMX-120 (2/4)
3-Jan-2004
AMX-120.S01
A2
Titel
Size
File:
Date:
7654321
C58
C112
R143
47u/25V
22P
3K9
R157
36K
VR21A
LEVEL
R171
R115
C60
47u/25V
2
W50K
R127
12K
4K7
C62
J4
47u/25V
U21B
POST
AUX-1
VR16
W50K
AUX-POST
8K2
R172
(PRE)
LD4
TR8
PEAK
RED
BR
PGND
22P
C114
+VCC
1K5
R136
LEFT-BUS
BAL
VR22
W50K
R98
10K0
1
U21A
NJM4580M
R116
22P
C113
4K7
RIGHT-BUS
R173
R97
12K
10K0
36K
R158
7
R160
36K
R174
R118
C68
12K
47u/25V
4K7
1
LEFT-BUS
BAL
VR24
W50K
R100
10K0
U20A
NJM4580M
R119
22P
C115
4K7
RIGHT-BUS
R99
R175
10K0
R159
12K
36K
7
NJM4580M
3
22K
R145
47u/25V
3K9
VR23A
LEVEL
2
W50K
R129
22K
C66
R146
47u/25V
3K9
3
3K9
R144
C59
47u/25V
VR21B
LEVEL
6
W50K
R128
22K
5
R92
C107
6K8
2.2u/50V
4K7
R117
R106
47K
TR7
R107
BR
UNINSERTED
C65
47K
VR23B
LEVEL
6
W50K
R130
5
22K
C67
J5
47u/25V
U20B
POST
NJM4580M
AUX-1
VR17
W50K
AUX-POST
8K2
R176
(PRE)
R120
4K7
47K
R108
LD5
TR10
PEAK
RED
BR
TR9
R109
PGND
BR
UNINSERTED
47K
R138
R93
C108
+VCC
1K5
6K8
2.2u/50V
C14
R42
22P
10K0
RSRN
3c5e1a4d2b
C57
47u/25V
1
10K0
R48
3
2
R304
1K2
10K0
R43
100P
C130
T
TN
X7
LEFT(MONO)
LINE IN 5/6
U19A
JY-6351G-02-250
20K
R188
NJM4580M
R45
SW6A
C13
C133
10K0
R49
10K0
PS-22E85L
+4/-10 DB
22P
100P
C35
R44
22P
10K0
RSRN
3c5e1a4d2b
R50
10K0
R305
1K2
C134
100P
T
TN
RIGHT
C61
R53
47u/25V
10K0
6
R51
7
10K0
C41
R57
22P
10K0
R64
RSRN
3c5e1a4d2b
10K0
R307
C138
T
TN
C64
R61
1K2
100P
47u/25V
10K0
6
R58
7
10K0
R190
20K
U18B
NJM4580M
10K0
R60
5
SW7B
PS-22E85L
+4/-10 DB
22P
C39
100P
C143
X10
JY-6351G-02-250
C158
NJM4580M
U18~ U21=
C154
C153
C151
100n
84
100n
84
100n
84
100n
84
+VCC
U21C
U20C
U19C
U18C
C159
100n
C157
100n
100n
C152
C150
100n
-VCC
10K0
R63
20K
R191
R189
20K
C63
47u/25V
RSRN
R306
C136
T
TN
R62
1K2
100P
10K0
2
R56
1
3
10K0
U18A
NJM4580M
R59
SW7A
PS-22E85L
22P
C37
C137
100P
10K0
+4/-10 DB
U19B
NJM4580M
C40
R54
22P
10K0
3c5e1a4d2b
10K0
R52
5
SW6B
PS-22E85L
+4/-10 DB
22P
C36
100P
C135
X9
X8
JY-6351G-02-250
JY-6351G-02-250
LEFT(MONO)
LINE IN 7/8
RIGHT
1 2 3 4 5 6 78
D
C
B
A
D
8
C
B
A
VER021229
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KEVIN LIN.
RevisionModel No:
Drawn By:
Sheet
AMX-120 (3/4)
7654321
C103
5
J6
47u/25V
U12B
U11B
POST
NJM4580M
R202
20K
NJM4580M
R89
SW8B
C50
C149
AUX-1
(PRE)
10K0
PS-22E85L
+4/-10 DB
22P
100P
VR18
W50K
AUX-POST
8K2
R184
R140
R94
C109
+VCC
6K8
2.2u/50V
1K5
4K7
R123
R110
47K
LD6
TR12
PEAK
RED
BR
TR11
R111
+VCC
BR
47K
PGND
R244
-VCC
GR
LD15
GR
( 5) ( 18)
LD13
LEFT METER
GR
LD11
(-20) (0)
GR
LD9
UNINSERTED
TR13
U8C
LM339
14
U8B
LM339
1
U7C
LM339
14
U7B
LM339
1
HR
8
9
6
7
8
9
6
7
R250
470R
+VCC
R253
820R
10
11
R254
1K
4
5
R252
150R
10
11
R246
110R
4
5
10R
R251
PGND
R247
470R
R103
10K0
D1B
R245
120R
+VCC
D1A
DA204K
DA204K
U8D
U8A
U7D
U7A
PGND
LM339
13
LM339
LM339
13
LM339
-VCC
LD16
GR
LD14
120R
TR14
LD12
LD10
HR
GR
GR
GR
2
2
R225
D4
D2
RLS4148
6
RLS4148
2
R258
100K
L-METER
D5
RLS4148
7
5
D3
RLS4148
1
3
C186
NJM4580M
C104
C105
47u/25V
47u/25V
+VCC
47R
R243
100n
C182
PGND
2K
GR
LD8
PH PWR
4K7
R124
PWR ON
LD7
RED
PGND
PHANTOM
312
U8E
LM339
312
U7E
LM339
-VCC
U18~ U21=
47R
R242
PGND
100n
C178
C184
R262
C191
U6B
R260
100K
NJM4580M
R261
C190
U6A
R259
100K
NJM4580M
100n
84
U12C
100n
84
U11C
+VCC
10K0
47u/25
10K0
47u/25
PGNDPGND
PGND
PGND
R255
100K
R-METER
C187
100n
C185
100n
-VCC
C99
C48
R81
C124
R147
47u/25V
22P
10K0
22P
3K9
R166
36K
VR28A
LEVEL
R308
1K2
100P
C146
R183
R121
C101
47u/25V
2
W50K
R133
C97
R85
LEFT-BUS
12K
4K7
1
22K
47u/25V
10K0
2
R82
3
1
10K0
3
BAL
VR29
R102
U12A
NJM4580M
U11A
W50K
10K0
20K
R201
NJM4580M
R84
SW8A
C47
C147
10K0
R86
10K0
PS-22E85L
+4/-10 DB
22P
100P
C125
R148
C100
C49
R83
R122
22P
3K9
47u/25V
22P
10K0
4K7
RIGHT-BUS
R185
R101
R87
R309
C148
12K
10K0
36K
R167
VR28B
LEVEL
10K0
1K2
100P
6
W50K
R134
C102
47u/25V
10K0
R90
7
6
22K
R88
5
7
10K0
Titel
INPUT STAGE ( CH9-CH10)
AMX-120
3-Jan-2004
AMX-120.S02
A2
Size
File:
Date:
T
RSRN
TN
3c5e1a4d2b
LEFT(MONO)
LINE IN 9/10
84
T
RSRN
TN
3c5e1a4d2b
X19
JY-6351G-02-250
X20
JY-6351G-02-250
U6C
NJM4580M
RIGHT
1 2 3 4 5 6 78
D
C
B
A
D
8
LEFT
MAIN OUT
RIGHT
C
PHONES
LEFT
CTRL ROOM OUT
RIGHT
B
A
VER031229
44of
KEVIN LIN.
RevisionModel No:
Drawn By:
Sheet
C400
4d
5K1
2b
TN
6
W50K
X12
C118
R231
C73
47u/25V
22P
3K6
R209
120R
R162
3c5e1a
RSRN
30K
JY-6351G-02-250
T
R211
120R
MOUT-L
R65
10K0
7
C74
47u/25V
5
U15B
NJM4580M
RIGHT
R226
18K
MAIN MIX
C71
47u/25V
7
U14B
NJM4580M
5
6
LEFT-BUS
C117
R179
22P
AMX-120 (4/4)
3c5e1a
RSRN
R210
120R
7654321
30K
R163
22P
C119
3K6
R230
47u/25V
C116
VR25B
LEFT
MAIN MIX
R178
22P
C72
4d
2b
TN
2
W50K
VR25A
5K1
X15
JY-6351G-02-250
T
R218
120R
MOUT-R
R72
10K0
1
C83
47u/25V
3c5e1a
C121
3
U15A
NJM4580M
18K
R227
C81
47u/25V
1
U14A
NJM4580M
3
2
RIGHT-BUS
4d
22P
2b
R214
R70
120R
10K0
6
2
X16
JY-6351G-02-250
R215
7
5
1
U22A
3
ROOM
CONTROL
PHONES/
R216
120R
U22B
BA15218N
BA15218N
22P
C122
22P
C46
7K5
R238
C80
47u/25V
120R
6
2
R71
10K0
C82
36K
R164
VR27A
2TK TO
CTRL ROOM
R217
7
U23B
5
1
U23A
3
47u/25V
1
3
2
W50K
27K
R234
123
R219
120R
120R
BA15218N
BA15218N
R67
10K0
U17A
NJM4580M
C45
L-METER
3c5e1a
22P
4d
SW2A
2b
R165
7K5
R239
C86
47u/25V
PS-22E85L
R223
R76
36K
X18
JY-6351G-02-250
120R
R222
10K0
7
5
6
W50K
VR27B
456
3c5e1a
120R
C93
47u/25V
U17B
R235
4d
27K
P
2b
NJM4580M
R-METER
SW2B
PS-22E85L
R224
120R
X17
JY-6351G-02-250
+5VD
TR20
+VCC
TR21
D12
CN1
7805
7815A
1N4002
SW11
AC IN
C403
1000uF/16V
R444
47u/25V
D16
RLS4148
C408
1000uF/35V
R445
PGND
PGNDDGND
PGND
0R0
C404
D11
0R0
D13
PGND
47u/25V
RLS4148
C409
1000uF/35V
1N4002
R241
-VCC
TR22
7915A
D14
C401
47uF/100V
C176
100n
C91
47u/25V
84
U23C
84
U22C
47R
1N4002
BA152 8N
BA152 8N
R240
PHANTOM PWR
PHANTOM
C402
47R
PH PWR
TR23
47uF/100V
C177
C92
R443
TIP122
C405
100n
47u/25V
10R
100uF/100V
SW10
D15
20K
R440
C406
R442
10K0
R441
1N4002
47uF/100V
390K
ZD1
1N5261
(47V 0.5W)
C407
47uF/100V
PGND
AMX-120
3-Jan-2004
AMX-120.S03
STEREO AUX & SENDS & MAIN OUT & 2TK & CTRL R & PHONES
A2
Titel
Size
File:
Date:
AUX SENDS
R208
120R
22P
C38
R46
22P
C42
3c5e1a
4d
2b
T
RSRN
TN
R207
C233
47u/25V
7
U24B
5
6
36K
6K2
R322
AUX SENDS
C70
47u/25V
1
2
36K
R161
AUX-1
120R
R192
3
X11
JY-6351G-02-250
20K
NJM4580M
VR30
U24A
W50K
NJM4580M
LEFT-BUS
LEFT-BUS
AMX-120 NOT USE
5K11
R177
C77
47u/25V
W50K
15K
47u/25V
1
U13A
NJM4580M
3
2
22K
R131
C188
100P
30K
R205
22P
C43
VR26A
R203
AUX RETURNS
C69
C44
22P
R206
VR26B
R204
C75
30K
47u/25V
W50K
15K
R180
6
RIGHT-BUS
5K11
7
RIGHT-BUS
5
R132
C189
C78
22K
100P
47u/25V
U13B
NJM4580M
LEFT-BUS
C120
22P
R232
2TK TO MIX
R194
1K
C76
C79
20K
3
47u/25V
47u/25V
6
2
7
5
R193
C144
R233
1
R181
20K
100P
1K
5K11
R66
U16B
SW1A
10K0
NJM4580M
PS-22E85L
C123
22P
RIGHT-BUS
P
C85
R200
C84
6
20K
47u/25V
47u/25V
2
5
1
R182
3
R195
4
5K11
U16A
20K
C145
R75
NJM4580M
100P
SW1B
10K0
PS-22E85L
C174
100n
84
C170
100n
84
C168
100n
84
C166
100n
84
C162
100n
84
C160
100n
84
+VCC
U13C
U14C
U15C
U16C
U17C
U24C
C175
100n
C173
100n
C169
100n
C167
100n
C165
100n
C161
100n
-VCC
NJM4580M
NJM4580M
AUX-1
EFXRTN-L
EFXRTN-R
TAPE OUT
TAPE IN
1 4
X21
SCP6873NS3232
L(WHITE)
D
C
2 5
R(RED)
6
U24=
3
B
U13~ U17=
1 2 3 4 5 6 78
A
PCB : AMX-120FX Top Overlay
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