Alto OEX-400 User manual

Service Manual
www.altoproaudio.com
Version: 1.2
Model: OEX-400

CONTENT
1. Introduction.............................................................................................1
2. Specification............................................................................................2
3. Block Diagram.........................................................................................4
4. Schematic Diagram.................................................................................5
5. Wiring Diagram......................................................................................10
6. Printed Circuit Board..........................................................................11
7. Exploded View & Mechanical Parts List..................................................14
8. Electrical Parts List.............................................................................19

1. Introduction
Trolley appearance
2 (two-SPEAKER) + 1 (7-channel mixer super combination)
One-way full-range speaker system
4 XLR MIC input with ultra low noise microphone pre-amplifiers and PHANTOM power+48V
1 stereo LINE input
Warm, natural 2-band EQ for each channel
Precision level control
24-bit DSP effects with powerful algorithms (16 presets)
Extremely high headroom offering excellent dynamic range
Plastic reinforced cabinet (polypropilene)
Two 10m speaker cables
Two folding speaker
Compartment for store following accessories:
350W (EIAJ) of Power
Folding speaker 2 10"
Power cord 1 IEC power cord
Customized Speaker Cable 2 10m
MIC 2 5m
Accessory List:
- 1 -

Mixer Section
2.Technical Specification
- 2 -

Speaker Section
Physical
Power Section
- 3 -

1234567 8
A
B
C
D
8
7
6
5
4
3
2
1
D
C
B
A
2-STAGE EQ
LOW HI
4
5
2
3
1
X4
LEFT(MONO)
4
5
2
3
1
X5
RIGHT
MIAN-BUS DFX(DSP)
2-STAGE EQ
CH INPUT
(CH1~3)
X6
TAPE INTAPE OUT
4
5
2
3
1
X8
PRESETS
MUTE
DSP FOOT
MAIN-BUS
DSP BOARD
7-STAGE EQ
63HZ
160HZ
400HZ
1K
2.5K
6.3K
16K
MAIN LEVEL
MASTER METER
MONITOR METER
MONITOR LEVEL
X4
T
R
S
X7
T
R
S
X5
T
R
S
MONITOR OUT
PHONES OUT
LEVEL
DSP/FX AUX1 POST
X1
X2
X3
X1-3A
XLR&TRS
5
6
4
3
1
2
T
R
S
X1-3B
XLR&TRS
1
2
3
X9
XLR
LOW HI
LEVEL
DSP/FX AUX1 POST
2-STAGE EQ
LOW HI
LEVEL
DSP/FX AUX1 POST
BAL/UNBAL
CH INPUT
CH4/5
BAL/UNBAL
CH6/7
STEREO INPUT
STEREO UNBAL INPUT
AUX RETURN LEVEL
DFX(DSP)
LOW BOOST 1
2
3
4
J13
CON4
POWER MODEII
RMS 300W
X14
T
R
S
MASTER SPK OUT2
STEREO OUTPUT
STEREO OUTPUT
AUX RETURN
X6
T
R
S
FOOTSWITCH
FX SEND
X13
T
R
S
MASTER SPK OUT1
POWER_CONNECT POWER SUPPLY
+22V
-22V OEX-400_MIXER
+15V
+5V
-15V
- 4 -
3. Block Diagram

12345678
A
B
C
D
87654321
D
C
B
A
MAIN SECTION
OEX-400_2.SCH DSP SECTION OEX-400_3.SCH 7 BAND EQ OEX-400_4.SCH
EQ HI
10KHZ
LO
C7
47u/25V
3
21
U2A
4580M
R124
1M
C100
22P
R4
3K9
R101
8K2
R100
8K2 C87
4N7(M) R102
8K2
C82
4N7(M)
C8
47u/25V
100HZ
C3
47u/25V
R50
10K
R1
3K9
C4
47u/25V C64
22P
R2
3K9
R51 10K
C65 22P
C5
47u/25V
3
21
U1A
4580M
X1
X2
X3
X1A
XLR&TRS
5
6
4
3
1
2
T
R
S
X1B
XLR&TRS
C1
47u/25V
R19
22K
C2
47u/25V
R20
22K
1
2
3
4
5
6
7
8
9
10
J6
CON10
1
2
3
4
5
6
7
8
9
10
J7
CON10
C13
47u/25V R6
3K9
C15
47u/25V R7
3K9
X1
X2
X3
X2A
XLR&TRS
5
6
4
3
1
2
T
R
S
X2B
XLR&TRS
C11
47u/25V
R23
22K
C12
47u/25V
R24
22K
C14
47u/25V R8
3K9
C27
47u/25V R12
3K9
X1
X2
X3
X3A
XLR&TRS
5
6
4
3
1
2
T
R
S
X3B
XLR&TRS
C25
47u/25V
R27
22K
C26
47u/25V
R28
22K
CH1-
CH1+
CH2-
CH2+
CH1 XLR INPUT
CH1 TRS INPUT
CH2 XLR INPUT
CH2 TRS INPUT
CH3 XLR INPUT
CH3 TRS INPUT
R52
10K
R91
12K C66
22P
5
67
U1B
4580M
C6
47u/25V
R21
22K
5
67
U2B
4580M
R132
36K
C102
22P
C10
47u/25V
R22
22K
R103
8K2
C9
47u/25V
13
2
VR1
B50K
13
2
VR2
B50K
R3
3K9
1 3
2VR3
W50K
J1 PRE/POST
R92
20K
1 3
2VR4
W50K
R53
10K
MAIN-BUS
FX-SEND
EQ HI
10KHZ
LO
C19
47u/25V
3
21
U4A
4580M
R125
1M
C101
22P
R5
3K9
R105
8K2
R104
8K2 C88
4N7(M) R106
8K2
C83
4N7(M)
C21
47u/25V
100HZ
R54
10K
C67
22P
R55 10K
C68 22P
C16
47u/25V
3
21
U3A
4580M
R57
10K
R93
12K C70
22P
5
67
U3B
4580M
C18
47u/25V
R25
22K
5
67
U4B
4580M
R133
36K
C104
22P
C24
47u/25V
R26
22K
R107
8K2
C22
47u/25V
13
2
VR5
B50K
13
2
VR6
B50K
R9
3K9
1 3
2VR7
W50K
J2 PRE/POST
R95
20K
1 3
2VR8
W50K
R59
10K
MAIN-BUS
FX-SEND
EQ HI
10KHZ
LO
C20
47u/25V
3
21
U6A
4580M
R126
1M
C103
22P
R11
3K9
R110
8K2
R109
8K2 C89
4N7(M) R111
8K2
C84
4N7(M)
C29
47u/25V
100HZ
R61
10K
C72
22P
R56 10K
C69
22P
C17
47u/25V
3
21
U5A
4580M
R58
10K
R94
12K C71
22P
5
67
U5B
4580M
C28
47u/25V
R29
22K
5
67
U6B
4580M
R134
36K
C105
22P
C30
47u/25V
R30
22K
R108
8K2
C23
47u/25V
13
2
VR9
B50K
13
2
VR10
B50K
R10
3K9
1 3
2VR11
W50K
J3 PRE/POST
R96
20K
1 3
2VR12
W50K
R60
10K
MAIN-BUS
FX-SEND
+VCC3
-VCC3
4
5
2
3
1
X4
SCJ-0658-1-Y
4
5
2
3
1
X5
SCJ-0658-1-Y
1
2
3
4
5
6
7
8
9
10
11
12
J9
CON12
4
5
2
3
1
X7
SCJ-0658-1-Y
4
5
2
3
1
X6
SCJ-0658-1-Y
S
T
R
4
5
2
3
1
X8
SCJ-0658-1-Y
S
T
RAUX RETURN
FX SEND
FOOTSW
C31
47u/25V
C193
100PC192
100P
C32
47u/25V
R154
120R
8 4
U3C
4580M
8 4
U4C
4580M
8 4
U5C
4580M
8 4
U6C
4580M
8 4
U1C
4580M
8 4
U2C
4580M
C120
0.1u
C126
0.1u
C121
0.1u
C127
0.1u
C122
0.1u
C123
0.1u
C124
0.1u
C125
0.1u
C128
0.1u
C129
0.1u
C130
0.1u
C131
0.1u
+VCC1
-VCC1
+VCC2
-VCC2
+VCC3
-VCC3
R138
10
R141
10
R140
10
R142
10
R143
10
R139
10
+VCC
-VCC
+VCC
-VCC
MOINTOR OUT
HEADPHONE OUT
1
2
3
4
5
6
7
8
9
10
11
12
J8
CON12
HP-OUT-R
HP-OUT-L
MO-OUT-R
MO-OUT-L
AUX-RETURN-L
AUX-RETURN-R
EFFECT-IN
FOOTSW
POWER&DSP
OEX-400_5.SCH
C94
4.7u/50V
C93
4.7u/50V
C92
4.7u/50V
C33
4.7u/63V NP
+VCC2
-VCC2
S
T
R
S
T
R
S
T
R
S1
SW SL2020 R252
22K
R163
22K
C146
47u/25V
1
2
J17
CON2
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
17 18
19 20
21 22
23 24
25 26
CN500
HEADER 13X2
R500
33R 5W
R501
47R 5W
1
2
3
CN501
CON3
+30VCC
-30VCC
+22VCC
-22VCC
CN501 connect to J14(SCH5)
CN500 connect to POWERMODEII
- 5 -
4. Schematic Diagram

12345678
A
B
C
D
87654321
D
C
B
A
EQ HI
10KHZ
LO
C35
47u/25V
3
21
U9A
4580M
R127
1M
C106
22P
R14
3K9
R113
8K2
R112
8K2 C90
4N7(M) R114
8K2
C85
4N7(M)
C36
47u/25V
100HZ
R97
12K C73
22P
5
67
U8B
4580M
C34
47u/25V
R31
22K
5
67
U9B
4580M
R135
36K
C107
22P
C39
47u/25V
R32
22K
R115
8K2
C37
47u/25V
R13
3K9
J4 PRE/POST
R63
10K
13
2
VR13
B50K
13
2
VR14
B50K
1 3
2VR15
W50K
R62
10K
1 3
2
VR16
W50K
R98
20K
FX-SEND
EQ HI
10KHZ
LO
C46
47u/25V
3
21
U11A
4580M
R128
1M
C111
22P
R18
3K9
R118
8K2
R117
8K2 C91
4N7(M) R119
8K2
C86
4N7(M)
C47
47u/25V
100HZ
R164
12K C74
22P
3
21
U10A
4580M
C45
47u/25V
R33
22K
5
67
U11B
4580M
R136
36K
C108
22P
C48
47u/25V
R34
22K
R116
8K2
C38
47u/25V
R17
3K9
J5 PRE/POST
R70
10K
MAIN-IN-EQ
TAPE-IN
13
2
VR17
B50K
13
2
VR18
B50K
1 3
2VR19
W50K
R69
10K
1 3
2VR20
W50K
R99
20K
FX-SEND
8 4
U7C
4580M
8 4
U8C
4580M
8 4
U9C
4580M
8 4
U10C
4580M
C132
0.1u
C133
0.1u C135 0.1u
C134
0.1u C136 0.1u C138 0.1u
C137
0.1u C139 0.1u
+VCC4
-VCC4
8 4
U13C
4580M
C144
0.1u
C145
0.1u
+VCC5
-VCC5
8 4
U11C
4580M
C140
0.1u
C141
0.1u
R144
10
R145
10
R146
10
R147
10
+VCC
-VCC
+VCC
-VCC
3
21
U12A
4580M
R161
62K
C109 22P
C40
47u/25V
R71
10K
5
67
U14B
4580M
R36
22K
C110
22P
EFFECT-IN
5
67
U12B
4580M
R72
10K
C113 22P
C49
47u/25V
MAIN-BUS
MAIN-BUS
3
21
U13A
4580M
R165
2K2
C112
22P
DSP-IN
8 4
U12C
4580M
C142
0.1u
C143
0.1u
R65
18K
R64
10K C41
47u/25V
4
5
2
3
1
X13
SCJ-0658-1-Y
4
5
2
3
1
X14
SCJ-0658-1-Y
S
T
R
1
2
3
4
J12
CON4
C95
4.7u/50V
C96
4.7u/50V
4
5
2
3
1
X15
SCJ-0658-1-Y
C194
100P C195 100P
X12
UNBAL-4P
LCH IN
RCH IN
C53
47u/25V R74
22K
C54
47u/25V R75
22K
TAPE INTAPE OUT
R170 2.2K
R171 2.2K
TAPE IN
TAPE OUT
CH4/5-IN
TAPE-IN
TAPE-OUT
R35
22K
R168
10k
R73
10K
C196
1N5
5
67
U13B
4580M
R162
10K
C114
22P
1
2
3
X9
XLR-M
4
5
2
3
1
X10
SCJ-0658-1-Y
4
5
2
3
1
X11
SCJ-0658-1-Y
S
T
R
C43
47u/25V R15
3K9
C42
47u/25V R16
3K9
C44
47u/25V
R37
22K
C50
47u/25V R38 22K
C52
47u/25V
R39
22K
C51
47u/25V R40 22K
1
2
3
4
5
6
7
8
9
10
11
12
J11
CON12
1
2
3
4
5
6
7
8
9
10
11
12
J10
CON12
R67
10K
C78
22P
R66
10K
C75
22P
3
21
U8A
4580M
R78
10K
C79
22P
R76
10K
C76
22P
3
21
U7A
4580M
R81
10K
C80
22P
R77
10K
C77
22P
5
67
U7B
4580M
R68
10K
R80
20K
R79
20K
C97
47u/25V
C99
47u/25V
C98
47u/25V
CH4/5-IN
OUT1
OUT2
AMP MO OUT----NC
3
2
1U14A
4580M
+VCC1
-VCC1
- 6 -

12345678
A
B
C
D
87654321
D
C
B
A
3
21
U23A
4580M
R41
22K
C115 22P
R176
6K8
R42
22K 3
21
U16A
4580M
R173
5K6
C116
22P C55
47u/25V
R184
680R
R172
5K6
3
21U15A
4580M
R177
39K
C197
10P
MN-EQ-SOURCE
5
67U15B
4580M
R178
39K
C198
10P
R175
6K8
MN-EQ-OOL-2
MN-EQ-OOL-1
R120
8K2
R189
2K7 5
67
U16B
4580M
R43
22K
C117
22P
C56
47u/25V R44
22K
HP-OUT-L
HP-OUT-R
MO-OUT-L
MO-OUT-R
TAPE-OUT
R207
27K 3
21
U17A
4580M
C58
47u/25V R213 8K2
R137
36K
C81
22P
C59
47u/25V
R45
22K
3
21
U19A
BA15218N
5
67
U19B
BA15218N
C119
22P
R216
10K0
R159
120R
R160
120R
R158
120R
R157
120R
5
67
U17B
4580M
C61
47u/25V
R46
22K
3
21
U18A
BA15218N
5
67
U18B
BA15218N
R217
10K0
C118
22P
1 3
2VR22
W50K R214
100R 1/4W
R215
100R 1/4W
MONITOR OUT
MASTER(VOLUMES)
C57
47u/25V R200
100K
D20
4148
3
2
1
U20A
4580M
R199
100K
D16
RED
D14
YE
D11
GR
D10
GR
+10DB0DB-10DB-30DB
MN VMETER
8 4
U14C
4580M
8 4
U15C
4580M
8 4
U16C
4580M
8 4
U17C
4580M
C166
0.1u
C167
0.1u C169 0.1u
C168
0.1u C170 0.1u C172 0.1u
C171
0.1u C173 0.1u
8 4
U18C
4580M
C174
0.1u
C175
0.1u
R150
10
R151
10
+VCC
-VCC
8 4
U20C
4580M
C152
0.1u
C153
0.1u
+VCC6
-VCC6
R148
10
R149
10
+VCC
-VCC
8 4
U19C
4580M
C164
0.1u
C165
0.1u
1 3
2
VR21
W50K
MAIN-IN-EQ
1
2
3
4
J13
CON4
TO AMP IN
5 42
3 12
U21A
LM339
7 61
U21B
LM339
9 814
U21C
LM339
11 10 13
U21D
LM339
5 4
2
3 12
U22A
LM339
7 6
1
U22B
LM339
9 8
14
U22C
LM339
11 10
13
U22D
LM339
R84
10K
E
2C3
B
1
Q1
PNP
E
2C3
B1
Q2
PNP
R156
120R
D1
1N4148
R155
120R
R192
470R
D2
1N4148
R191
470R
R82
10K
D17
RED
D15
YE
D13
GR
D12
GR
R194
43R
R195
510R
R196
1.2K
R197
2.7K
R198
22K
D19
4148
C60
47u/25V
R201
100K
D21
4148
5
6
7
U20B
4580M
R202
100K
R83
10K
D22
4148
+VCC6
-VCC6
+VCC6
-VCC6
MO VMETER
+10DB0DB-10DB-30DB
+VCC6
-VCC6+VCC6
-VCC6
R247
10K
C190
47UF/25V
C191
47UF/25V
C188
47UF/25V
C189
47UF/25V
R248
1K
R249
10K NC
+VCC1
-VCC1
+VCC8
-VCC8
R253
4.7K
R254
4.7K
R262
15.0K
5
67
U10B
4580M
R264
27.0K
C238
100nF
R265
12.0K
C237
0.22u/50V
CI00185
C239
47u/25V
R255
27K
R255 IS NOT USED
- 7 -

12345678
A
B
C
D
87654321
D
C
B
A
5
6
7
U23B
4580V
R218
18K
C199
220N
R225
15K
C200
220N
MN-EQ-OOL-2
MN-EQ-OOL-1
63HZ FREQUENCY BAND
MN-EQ-SOURCE
13
2
VR24A
W100K R226
15K R227
15K
R174
5K6
3
2
1
U24A
4580V
R221
18K
C201
220N
R121
8K2
C202
220N
MN-EQ-OOL-2
MN-EQ-OOL-1
160HZ FREQUENCY BAND
MN-EQ-SOURCE
13
2
VR25A
W100K R122
8K2 R123
8K2
R232
1K2
5
6
7
U24B
4580V
R223
18K
C213
33N
R179
39K
C212
33N
MN-EQ-OOL-2
MN-EQ-OOL-1
400HZ FREQUENCY BAND
MN-EQ-SOURCE
13
2
VR26A
W100K R180
39K R181
39K
R234
1K8
3
2
1
U25A
4580V
R219
18K
C204
10N
R229
47K
C205
10N
MN-EQ-OOL-2
MN-EQ-OOL-1
1KHZ FREQUENCY BAND
MN-EQ-SOURCE
13
2
VR27A
W100K R230
47K R231
47K
R190
2K7
5
6
7
U25B
4580V
R222
18K
C206
10N
R47
22K
C207
10N
MN-EQ-OOL-2
MN-EQ-OOL-1
2.5KHZ FREQUENCY BAND
MN-EQ-SOURCE
13
2
VR28A
W100K R48
22K R49
22K
R233
1K
3
2
1
U26A
4580V
R224
18K
C211
1N
R203
100K
C210
1N
MN-EQ-OOL-2
MN-EQ-OOL-1
6.3KHZ FREQUENCY BAND
MN-EQ-SOURCE
13
2
VR29A
W100K R204
100K R205
100K
R235
3K3
5
6
7
U26B
4580V
R220
18K
C208
1N
R208
27K
C209
1N
MN-EQ-OOL-2
MN-EQ-OOL-1
16KHZ FREQUENCY BAND
MN-EQ-SOURCE
13
2
VR30A
W100K R209
27K R210
27K
R166
2K2
8 4
U23C
4580V
8 4
U24C
4580V
8 4
U25C
4580V
8 4
U26C
4580V
C176
0.1u
C180
0.1u C181 0.1u
C177
0.1u C178 0.1u C179 0.1u
C182
0.1u C183 0.1u
+VCC8
-VCC8
R152
10
R153
10
+VCC
-VCC
46
5
VR24B
W100K
46
5
VR25B
W100K
46
5
VR26B
W100K
46
5
VR29B
W100K
46
5
VR28B
W100K
46
5
VR27B
W100K
46
5
VR30B
W100K
R263
0R 1/4W
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