Alto SR500A Schematic

Service Manual

Model: SR500A

ALTO

REV.2

CONTENTS

1. Specifications

2. Block Diagram

3. Schematic Diagram

4. Printed Circuit Board

5. Test Procedures

6. Structur al Drawing

7. Exploded View & Mechanical Parts List

8. Electrical Parts List

Test Result

Rated Output.

w Load

Hi Load

Aux At 1KHz FLAT.

Aux 1KHz dB

100HZ:

01-1

Model No: SR500A Test Date:20050711 Tester: MO GUO ZHU

Test Item Test Conditions Spec Test Result Remark

1

Power Source AC: 230V；50 Hz

2 Idle Current AC 230 V No-Load 5 ±0.5 mV mV across R26 &R24
3

4

Power
Consumption
Rated Output Lo

A

Aux At 1KHz

W

W

: 4Ω 34~36V THD:0.25↓ V
: 8Ω 19~20V THD:0.3↓ _______V

A

FLAT

Rated W

Load 16Ω V _______V
Load ____Ω （25V ）

Load____Ω （50V ）
Load____Ω （70V ）
Load____Ω （100V ）

5

Maximum at

Output 10% THD

7 Hum or Noise

Load Ω

VR Max （Low ） 25↓ mV mV DSP OFF

V V

V V
V V
V V

W W FLAT

VR Max（Hi ） 20↓ mV mV DSP OFF

8

Tone control

Response

Input From Aux

Output At 1W

10KHZ: dB 10KHZ: dB

dB 100HZ: dB

9 Puncture Voltage 5mA ， 5Sec 3750V V

10 MONITOR Aux 1KHz dB Load Ω

FLAT
MONITOR NO: AUX,TAPE,TUNER,CD,MIC1,MIC2
CD PLAYER 1KHz 0dB
TUNER AM/FM

PRIORITY MIC1
TEL.PAGING 1KHz____dB

Load____Ω_______V

G-T___dB；
G-R___dB。

G-T___dB；G-R___dB。

ZONE PAGING 100V ALL/ Z1，

Z2， Z3， Z4

AC : OUTPUT
REMOTE AC OUT or DC OUT

FLAT

Test Result

Model No：SR500A Test Date: 20050711 Tester：MO GUO ZHU

Test Conditions

Test Result

FLAT Rated

FLAT Output

Output 36V

FLAT Output at

dB dB % %

dB % %

dB % %

dB % %

dB dB % %

dB % %

dB % %

dB % %

dB dB % %

dB % %

dB % %

dB dB % %

dB % %

dB % %

dB % %

dB dB % %

dB % %

dB % %

dB % %

dB dB % %

dB % %

dB % %

dB % %

dB dB % %

01-2

Test Item 1. Input

2. Signal/Noise 3. Distortion at

Sensitivity

LINE

Low OUT

Hi OUT

Output 36V/20V

Load 4 Ω

-3 ±0.5 dBV

0.5±0.3 dBV

FLAT Rated

Output 36V/20V

Load 4Ω

80↑ dB
80↑ dB

at 2V Load 4Ω

TUNER

CD dB

AUX dB

AUX2

TAPE dB

TUNER

CD dB

AUX dB

AUX3

TAPE dB

TUNER

CD dB

MIC

LOW -44 ±0.5 dBV

HI -44 ±2 dBV

24V dB

60↑ dB

60 ↑ dB

UNBAL

MIC dB

MIC-2

LINE dB

24V dB

UNBAL

MIC dB

MIC-3

LINE dB

24V dB

UNBAL

MIC dB

MIC-4

LINE dB

24V dB

UNBAL

Remark

1. When the above item are tested, short-circuit the row pin of 1, 2 pin of 313115-1(DSP board)CN1. After

test, remove the short circuit terminal.

2. Load connection: connect 4Ohm load to LOW output, and 8Ohm to Hi output.

3. Please check if bass BOOST circuit is normal. When the bass output is below 17V(ON LOAD),BOOST

circuit does not operate. When the bass output is above 17V(ON LOAD), BOOST circuit starts to operate.

Authorization by： Check by：

1W

0.8↓ %

0.5↓ %

2↓ %
2↓ %

4. Distortion at
Rated

FLAT Rated

Load 4 Ω

0.5 ↓ %

0.1 ↓ %

0.5 ↓ %

0.3 ↓ %

5. Frequency
Response

2V Load 4Ω

4

02-1

1

第版

D

C

B

A

VER1.0

1/1

Revision

MO GUO ZHU

Sheet of:

Drawn By:

HI SPEAKER

AMP

HI POWER

321

HI PRE

AMP

HPF

DSP MODULE

LOW SPEAKER

AMP

LOW PRE LOW POWER

AMP

LPF

POWER SUPPLY

SWITCH

HI

LOW

V+ & V- V+ & V-

HI V+

LOW V+

T6.3A

T6.3A

HI V-

LOW V-

T6.3A

T6.3A

Title

SR500A

SR500A

Number

A3

Size:

Date:

File:

SR500A BLOCK DIAGRAM

238094

130 deg SW

VOLUME

MIX AMP PRE AMP

POWER SWITCH

1 2 34

SIGNAL INPUT

LINE IN

D

C

B

AC INPUT

A

7654321

03-1

8

1 第版

SW1

VR-SW

6

5
1

+15V

D

C

MIC2

CN-BAL-MALE

1
3
2

MIC1

XLR

X3

4

X1X2

SW PS-22E85L

HIGH INPUT
+4dB

B

A

1 2 3 4 5 6 78

0.01uF/400V

0.1u
C15

470u/25V SLL

0.1u

C11

470u/25V SLL

47u/63V

10K

R7

C21

47u/63V

10K

R12

C22

FL5R

L2

FL5R

L3

12V1W

R22

1

2
3

12V1W

SW2B

P

SW PS-22E85L

ZD2

ZD5

4

5
6

1
2
3
4
5
6

C27

10E

SW2A

IC3E

C14

33079

11 4

C10

6K8

R1

10K

R2

_

6

33079

5

+

6K8

R11

10K

R10

IC1C

_

9

33079

10

+

R16

15K

R19
15K

12V1W

ZD3

12V1W

15K

ZD4

GND

IC1E

33079

11 4

-15V

0.0033u

C5

IC1B

13

12

R18

0.0033u
C16

22P

47u/63V

7

8

C23

_
33079

+

C1

47u/63V

C2

22P

C20

15K

R15

14

IC3D

1K2

2

R9

6K8

R3

10K

R4

10u/63V

390E

R14

C28

7

DL1

R
G

SIGN/LIMIT

0.0033u

3

2
3
4

1

CLIP

3

SIGNAL

C19

22P

33079

47u/63V

C7

C17

R5

13

1

12

IC1A

10u/63V

1

_

IC3A

+

L1

1

+5VD

2

1000u/6V3

C25

470u/25V SLL*

22P

C6

10K

2

33079

_

3

+

VR1
D50K

1

2

C18

10u/63V

2

3

TP-SEV1924-03

3

5

D1

BYV27

4

+15V

-15V

C29

_
33079

+

C24

IC3D

2u2 100V

R13

CN2

1920
1718
1516
1314
1112
9 10
7 8
5 6
3 4
1 2

CN-10PX2-180

14

4.7K

R17

2

1

3

NC

NC

OUT

FB10FC11GND12GND13OSC

SS

15

15K

C13

0.033u

10

6

NC

R6

C8

330E

HIGH

LOW

9

6
5

9

16

NC

5

TO 313120-1 AMP PCB

IC3C

_

33079

+

22P

C26

820E

IC3B

_

33079

+

7

IC2

V+

NC8NC

L4962

GND4GND

14

3K9

R8

+5VD

+5VA

R21

0.0022u

CN1

1
3
5
7
9
11
13

CN-7PX2-F

8

7

C12

D

C

2
4
6

-15V

8

10

+15V
12
14

B

C4

C9

330P

220u/63V

A

Title

SR400A-PRE

Size:A3Number

Date:

2003/12/10

File:

PS 4HA

P-110018-SR400A

Sheet of:
Drawn By:

Revision

VER1.0

1/1

Lian Ming Tan

7654321

03-2

8

R39

R36
820E

D

DL2

100P

R92

R93

R94

6

_

10K

5

+

MC33078

+5VA

FROM 313127 INPUT PCB

F1
T8A

0.01uF400V
C11

F2
T8A

F3
T8A

F4

T8A

D5

400V/10N

RED
YEL
BLA
YEL
RED

PT-PS5HA-220V

CN1

CN-7PX2-F

KBU806

C

B

A

1K

22K

10U NP

IC7B

7

C45

1

2

3

4

5

6

7

8

9

10

11

12

13

14

10000U/50V

10000U/50V

BP25-06PWS

KBPC25

D4

C1

4002

BREAKER

2

R98

3

1K

D33

D32

4148

4148

-15V

+15V

R78
100E PTC

47E/5W

R79

2200U/63V

1

3

Vin

Vout

GND

C18

IC5

2

7815

C19

1

3

GND

Vin2Vout

IC4

7905

D1

C15

10000/80V

C16

10000/80V

D3

1N4002

AC INPUT

-0.56V

TR12

2N5551

R40

R56

12K

4K7

D10

-15V

1N4148

-15V
48

_
+

MC33078

+15V

C40

C38

1

C43

10/25V

C42

10/25V

47K

IC7A

100P

100K
R90

R51
12K

+VCC1

+15V

IC3 7805

Vin

+VCC2

-VCC2

R21

R55
68K

1

0.1V

R49

R42

68K

+15V

Vout

GND

2

C23

D12

R50

4K7

1N4148

TR12
2N5401

0.58V

+5VA

3

1000U 6.3V

C37

-15V

-VCC1

68E

TR11

NJE350
C22
100P

D19

10V 1W

0.001U

C13

1K5

+1.4V

R23

TR1

-0.33V

R22

MJE802

560E

VR1 500E

-1.4V

470E

0.1U

C21

100P

TR10

MJE340

R34
820E

R35
68E

DL1 47P

R71
15K

R70

2

3

6

5

R70
47K

R74
4K7

R76

R45

12K

12K 2W

9.6V

C25

27.5V

R77
8K2

220U/25V

C14

10/50V

R32

C27

10 1W

8K2

220U 25V

D15

-7.6V

R33

R52

12K2W

47K

-15V
48

IC5A

R11

_

1

+

10K

MC33078

+15V

R73
10E

IC5B

_

7

+

MC33078

+15V

14.8V

R57

150K

-8.3V

C29

1U/50V

TR21
BC847

C34

1000U/6V3

D18

1N4002

D29

C35

0.0047U

C20

0.0047U

D17

1N4002

D16

1N4002

12K

C2

1U 50V NP

R3

22K

R72
10K

R71
10K

TR20
BC847

TR26
BC847

OFFSET PROTECTION

R69
47E

R67
8K2

1N4002

C17

0.0047U

R31

12K

R43

12K

C24

0.0047U

R63
8K2
R62

47E

R64
47K

R2

680E

R4
1K

C6

R32

10UF/50V

33K

R21
10K

TR22
BC857

C30

220U/50V

R59
330E

R73

10.97V

10K

R60
33K

TR27
BC857

C28

470P

32.1V

R54

R68

2K2

47K

TR7

TR6

MJE340

MJE15030

R30

R29
470E

4E7

R37

R27
470E

4E7

TR8

TR15

MJE15031

MJE350

R65
2K2

-32.4V-27.7V

C31

470P

IC1

TDA7294

+VCC1

78

12

13

6

2

14

3

5

4

10

MUTE

9

11

ST-BY

D1

TDA7294

4148

1

15

-VCC1

SOFT START

R46
10K

R58
10K

14.2V

11.1V

R47
10K

11.6V

0.1U
C26

1N4148

TR17
BC857

-15V

R44

1K

C3

22UF/50V

10UF/50V

R12
22K

TR13
BC32725

R48
470E

D14

TR19

NJE15031

0.0018U

TR25

MJE340

TR4

2SC5200

or NJL21184

R29

R25

10E

2SA1943

or MJL21193

TR23
MJE350
C32

0.0018U

R66

1K

C4

RL1

OZ-SS-124LM1
DC 24V 16A

R38
390E

TR9

TIP36C

or SIMILAR

C33

TR1

2SC5200

or NJL21184

10E

R26

R19

0E2 5W

R24

R20

0E2 5W

or MJL21193

2SA1943

TR5

TR2

TR24
MJE15030

R53

TR18

390E

TIP35C

R1
22K

HIGH OUT +

R12
10E 0.5W

C5

0.1U

D8

TR16

1N4148
R30
10K

LOW OUT+

+VCC2

D7

1N4002

6A2

+VCC1

D8

1N4002
D28

0E2 5W

0E2 5W

D30

1N4002

D9

-VCC1

6A2

D13

1N4002

-VCC2

S1

Hi SPEAKER

S2

GND

BC857

S10

LOW SPEAKER

S9

GND

D

C

B

A

1 2 3 4 5 6 78

03-4