Alto MICRO Service Manual
MODEL: MICRO 3/3A/4/4A
Service
www.show-pa.com
Version 1.0
CONTENT
1. INTRODUCTION……………………………………………………1
2. TECHNICAL SPECIFICATION……………………………………2
3. BLOCK DIAGRAM & SCHEMATIC DIAGRAM…………………3
4. PCB LAYOUT ………………………………………………………9
5. TEST PROCEDURE………………………………………………11
6. EXPLODED VIEW & MECHANICAL PARTS LIST… …………13
7. BOM ………………………………… ……………………………...19
1. INTRODUCTION
- 1 -
This is a set of compact combination speakers. The MICRO series contain active
and passive models. MICRO 3A preamplifier is made with 2 JIM2068, one stereo
integrated circuit LM4766 in post circuit, signal RCA with left and right input and
the output power is 80/30 W. MICRO 4A preamplifier is made with 2 NJM2068,
one stereo integrated circuit LM4732 in post circuit, signal RCA with left and
right input and the output power is 50W. Light weight, compact dimension , easy
for installation. MICRO 3A/4A , the cabinet is made with PP rubber and 30%
exsiccator with black gravel paint on its surface. Use silk with YS-25 core ,4.2 Ω
for its treble, enjoying clear tweeter and strong woffer.
4. TECHNICAL SPECIFICATION
2. TECHNICAL SPECIFICATION
- 2 -
Model No.
System type
Power Handing
SPL (1W/1m)
Frequency Response
Impedance
Crossover Frequency
Dimension(HxWxD)
Net Weight (kg)
Model No.
System type
Power Handing
SPL (1W/1m)
Frequency Response
Impedance
Crossover Frequency
Dimension(HxWxD)
Net Weight (kg)
Model No.
System type
Power Handing: HF
Power Handing: LF
SPL (1W/1m)
AMP
Frequency Response
Impedance
Crossover Frequency
Dimension(HxWxD)
Net Weight (kg)
Model No.
System type
Power Handing: HF
Power Handing: LF
SPL (1W/1m)
AMP
Frequency Response
Impedance
Crossover Frequency
Dimension(HxWxD)
Net Weight (kg)
MICRO 3
2Way
AES30W
87 dB
50 Hz-13 kHz (-10 dB)
8 Ohms
2.3-3 kHz (1m/W)
216.5 x 143.5 x 152.5 mm
2.21 kg
MICRO 4
2Way
AES60W
92 dB
40Hz-15 kHz (-10dB)
4 Ohms
2.3-3 kHz (1m/W)
287.5x169 x 201mm
4.63 kg
MICRO 3A
2Way
AES15W
AES30W
87 dB
50 W +50 W (extra) continuous EIAJ
50 Hz-13 kHz (-10 dB)
8 Ohms
2.3-3 kHz (1m/W)
216.5 x 143.5 x 152.5 mm
3.51 kg
MICRO 4A
2Way
AES30W
AES60W
92 dB
100 W +100 W (extra) continuous EIAJ
40 Hz-15 kHz (-10 dB)
4 Ohms
2.3-3 kHz (1m/W)
287.5 x 169 x 201 mm
6.41 kg
4
D
- 3 -
3.BLOCK
OUTPUT
preamp1
preamp2
preamp1
preamp2
654321
C
B
A
VER070112
of1
Revision
Lv Ping Tang
MICRO 3A
1-Mar-2007 Sheet 1
Model No:
Size
MICRO 3A .SCH Drawn By:
A3
File:
Date:
MICRO 3A
Titel
4O
MICRO M3A BLOCK
VR104
VR104
4O
D101
R?
RES1
2
D1T
POWER
1
3
4
TRANS
SW
L INPUT
D
C
R INPUT
AC230V/50HZ
1 2 3 4 5 6
B
A
D
- 4 -
preamp1
preamp1
preamp2
preamp2
OUTPUT
654321
C
B
A
VER070112
of1
Lv Ping Tang
Revision
Drawn By:
MICRO 4ABLOCK
MICRO 4A
1-Mar-2007 Sheet 1
Model No:
MICRO 4A BLOCK
A3
File:
Date:
Titel
Size
4O
MICRO M4A BLOCK
VR104
VR104
4O
D101
R?
RES1
2
D1T
POWER
1
3
4
TRANS
SW
L INPUT
R INPUT
AC230V/50HZ
1 2 3 4 5 6
D
C
B
A
654321
SCHEMATIC DIAGRAM
- 5 -
MICRO 3-XOVER(1/1)
D
LOW BRIDGE+
T3
T10
GND
C
LOW BRIDGE+
T2
J1
OUTPUT
3c
4d
2b
1a
5e
L2
0.4MH
C1
6U/100V
14U/100V
R1
6O/10W
0.2MH
C2
T1
HI OUT+
L1
LOW SPEAKER
T9
GND
HI SPEAKER
T4
GND
MICRO 3-X-1版
OUTPUT
J1
3c
4d
2b
1a
5e
L2
0.6MH
C1
1.5U/100V
R1
6O/10W
LOW BRIDGE+
T3
LOW BRIDGE+
T2
C2
10U/100V
T1
HI OUT+
L1
0.35MH
T10
GND
LOW SPEAKER
T9
GND
MICRO 3-X-2版
HI SPEAKER
T4
GND
OUTPUT
LOW BRIDGE+
T3
T10
GND
LOW SPEAKER
T2
LOW BRIDGE+
J1
3c
4d
2b
1a
5e
R1
12O/10W
0.35MH
T1
HI OUT+
L1
T9
GND
MICRO 3-X-3 OK版確認
HI SPEAKER
T4
GND
D
C
B
A
1 2 3 4 5 6
Titel
Size
MICRO 3-XOVER
Model No:
A4
1-Mar-2007 Sheet
Date:
File:
HB02380 MICRO 3-XOVER .SCH原理圖
MICRO 3-XOVER
Drawn By:
Revision
VER061221
of1
1
Lv Ping Tang
B
A
D
- 6 -
C
B
A
J2
INPUT
D3
K
T9
V-
R23
68K 0.5W
C28
0.15u
C29
0.1u
1
AC1
AC2
3
C3
0.15u
C7
0.1u
BR2
V+
BU10-04
Vac
C6
0.1u/275V
-15V
+15V
C5
33P
U2A
NJM2068LD
C27
33P
U4A
4
CN2
1
2
PL
1
1
GND
T10
T1
Vac
10K
R19
-15V
2
3
2
3
C26
-15V
+15V
48
_
+
+15V
C1
10K
R25
48
_
+
NJM2068LD
4.7u/25V
Z10
1
A
2
B
3
C
4
D
5
E
1 2 3 4 5 6
IN4737
IN4737
IN4737
IN4737
A K
Z9
A K
4.7u/25V
Z14
Z13
C25
C4
R24
30K
R14
30K
10K
10K
10P
R8
10P
R26
2
C20
0.1U
C18
0.1U
C16
0.15u
C8
0.1u
C30
0.15u
C31
0.1u
+Vc
C24
4700u/50V
C23
4700u/50V
-Vc
R28
2.2K
R27
56K
IN4004
D2
K
IN4004
C22
220u/25V
C21
220u/25V
2.2K
6
5
R15
56K
6
5
AAK
AAK
Z12
IN4737
Z11
IN4737
R16
1K
R20
U2B
_
+
NJM2068LD
C32
33P
1K
R29
U4B
_
+
NJM2068LD
R22
820E 1W
R21
820E 1W
C17
33P
R61
10u/50V
-INB
+INB
11
10
9
8
MuteB
MuteA
18
17
5
4
+INA
-INA
C66
C65
10u/50V
R54
20K
20K
27
VCC
-VEE
LM4732
2
U3
VoB
GND
VoA
1000u/50V
+Vc
C68
1000u/50V
25
19
12
7
-Vc
C67
R58
2.7O/2W
C64
0.1U
C63
0.1U
R57
2.7O/2W
L2
0.5MH
C2
4U/100V
1O/10W
R60
1K
R13
15K
C70
68u/25V
-Vc
R55
1K
C69
+Vc
R59
1K
R56
1K
C62
0.1U
21
22
20
14
16
15
C61
0.1U
R52
15k
C58
4.7u/25V
C56
15P
R17
7
1K
VR2
A10K
3
1
C15
4.7u/25V
2
C10
102
C9
101
R43
15K
R51
15K
C59
100u/35V
C57
4.7u/25V
C55
15P
C60
100u/35V
68u/25V CB00349
1,3腳信號輸入腳
5腳地
R30
7
1K
VR2
A10K
3
1
C33
4.7u/25V
2
C34
102
C35
101
2,4 .腳空腳
Titel
Size
MICRO 4A
Model No:
A4
1-Mar-2007 Sheet 1
Date:
MICRO 4A VER061210.SCH
File:
MICRO 4A
R1
Drawn By:
654321
MICRO 4A(1/1)
LOW BRIDGE+
T16
T13
GND
LOW BRIDGE+
T15
10U/100V
HI OUT+
L1
0.2MH
1
2
3
4
5
C11
T14
OUTPUT
Revision
T12
GND
GND
J3
A
B
C
D
E
VER070127
of1
Lv Ping Tang
LOW SPEAKER
HI SPEAKER
T11
D
C
B
A
654321
- 7 -
C45
10u/35V
R41
2.7O/2w
C41
0.1U/100V
C44
0.1U/100V
Drawn By:
MICRO 3A(1/1)
C46
0.1U/100V
SPO+
1
SPO-
1
J3
1
A
2
B
3
C
4
D
5
E
OUTPUT
1,3腳信號輸入腳
5腳地
2,4 .腳空腳
VER070127
of1
Lv Ping Tang
D
C
B
A
+Vc
D3
K
T9
V-
R23
68K 0.5W
C52
0.15u
C54
0.1u
1
AC1
AC2
3
C3
0.15u
C7
0.1u
BR2
V+
BU10-04
D
C
4.7u/25V
Z10
IN4737
IN4737
IN4737
Z9
IN4737
4.7u/25V
Z14
Z13
J2
B
INPUT
A
1
A
2
B
3
C
4
D
5
E
C49
C4
R14
15K
R34
15K
10K
10K
10P
R44
R8
10P
Vac
2
3
GND
T10
T1
Vac
2
3
C51
C5
33P
10K
R19
-15V
48
_
U2A
+
+15V
C1
C50
33P
10K
R35
-15V
48
_
U3A
+
NJM2068LD
+15V
C6
4
0.1u/275V
-15V
CN2
1
2
PL
+15V
NJM2068LD
1
1
2
C20
0.1U
C18
0.1U
C16
0.15u
C8
0.1u
C53
0.15u
C55
0.1u
+Vc
C24
4700u/50V
C23
4700u/50V
-Vc
2.2K
R38
56K
IN4004
D2
K
IN4004
C22
220u/25V
C21
220u/25V
2.2K
6
5
R15
56K
R37
6
5
AAK
AAK
Z12
IN4737
Z11
IN4737
R16
1K
R20
_
U2B
+
NJM2068LD
C56
33P
1K
R39
_
U3B
+
NJM2068LD
C17
33P
R22
820E 1W
R21
820E 1W
7
7
R40
1K
R17
1K
VR2
A10K
VR2
A10K
3
1
3
1
C15
4.7u/25V
C57
4.7u/25V
2
8
7
R27
47K 15K可改為
R30
1K
C34
4.7u/25V
C10
102
2
C9
101
C58
102
C59
101
R33
47k 15K可改為
C33
4.7u/25V
C35
470u/35V
C36
470u/35V
R29
1K
C47
10u/35V
13
U4B
LM4766
12
R32
1K
R31
1K
2
+IN A
Vcc A
-IN A
Vee
4
C48
0.1U/100V
R37
20K
C38 CB00027
22U/25V
C37 CB00027
22U/25V
+IN B
-IN B
+Vc
Vee
4
Titel
6
15
Size
A4
Date:
File:
1 2 3 4 5 6
C43
470u/35V
LM4766
C42
100u/35V
OUT B
GND B
10
3
U4A
-Vc
1
R42
2.7O/2w
OUT A
Mute A
5
Vcc B
Mute B
11
R36
20K
GND A
MICRO 3A
File:
1-Mar-2007 Sheet 1
MICRO 3A VER061210.SCH
MICRO 3A
- 8 -
4. PCB PLAYOUT
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