EN-30
ISSUE
DRAWING NO.
DRAWING TITLE
DATE
Filename:
ECO No.
DESCRIPTION OF CHANGE
L281 CT5 SR Channel.SchDoc
AMP019 Amp SR
Contact Engineer:
L281CT
15/01/2021
INITIALS
Printed:
5
10
Sheet
of
Notes:
Contact Tel:
01223 203201
Jon Henderson
A & R Cambridge Ltd.
Cambridge CB25 9QE
Waterbeach
A3
ARCAM
LIN
RV4000
1K
AGND
AGND
TR4005
BC856B
10
0V
C
40
14
82
P
AGND
TR4023
BC846B
10
0V
C
40
30
82
P
TR4002
2SC2690A
TR4021
KSA1220A
TR4001
MMBTA42L
TR
40
24
M
M
B
TA
92
L
0W
12
5
R
40
28
33
R
0W
12
5
R
40
96
33
R
0W
12
5
R
40
43
56
0R
0W
12
5
R
40
73
56
0R
0W125
R4030
10R
0W
12
5
R
41
10
22
R
0W
12
5
R
40
11
22
R
GND_B
GND_B
TR4003
2SC2690A
TR4018
KSA1220A
D
40
06
S
1D
D
40
10
S
1D
63V
C4008
22UF
63V
C4033
22UF
100V
C4005
1uF
GND_A
100V
C4032
1uF
GND_A
+VLIFT
-VLIFT
2W
R
40
55
0.18R
2W
R
40
65
0.18R
2W
R
40
64
0.18R
2W
R
40
54
0.18R
2W
R
40
53
0.18R
2W
R
40
63
0.18R
+Input SR
-Input SR
0W5
R4035
1R0
6
5
7
IC6000B
OPA1652AIDR
AGND
0W063
R4004
10K
AGND
D4000
BAV99
ERR +VE
ERR -VE
100V
C4001
470N
20C/W
HS4000A
5400-9130+0
20C/W
HS4001A
5400-9130+0
TR4014A
NJL1302DG
TR
40
14
B
N
JL
13
02
D
G
0W5
R4086
1R0
0W
12
5
R
40
68
10
0K
1206
FS4000
7.0A
1206
FS4001
7.0A
GND_SR
1
2
8mm
J4000
LINK
1
2
8mm
J4002
LINK
1
2
8mm
J4003
LINK
1
2
8mm
J4004
LINK
1
2
8mm
J4005
LINK
1
2
8mm
J4007
LINK
1
2
8mm
J4001
LINK
1
2
8mm
J4006
LINK
-SR Input
NF
AGND
P
40
65
P4059
P4074
P4066
P4067
P4055
P4056
P4035
P4041
P4017
P4047
P4064
P
40
92
P4044
P4029
P4060
P
40
32
P
40
42
P4026
P4048
P
40
24
P4046
P4099
P4061
P4100
P4080
P4079
P4073
P4096
P4109
P4115
P4114
P4107
P4108
P4098
P4116
P
41
18
P4005
P4006
P4001
P4004
P
40
10
P
40
16
P4063
P4078
P4111
P4015
P4023
P4037
P4020
P
40
18
P4013
P4014
P4019
P4028
P4049
P4030
P4025
P4057
P4027
P4031
P4040
P4043
P
40
50
P
40
72
P4076
P4090
P
40
89
P4085
P4088
P4036
P4039
P4054
P4095
P4091
P4103
P4102
P4086
P4094
P4101
P4077
P4113
P4097
P4068
P
41
04
P4058
P4093
10
0V
C
40
24
10
0N
100V
C4020
100N
FILM
-SR Input
Out SR
Out SR
1
2
M20-973
CON4000
HARWIN
SHORT SR
SHORT SR
TR4000
MMBTA42L
25V
C4000
1uF
P4000
P4003
P4008
Bias measurement
ERR +VE
ERR -VE
BIAS SR+
BIAS SR-
BIAS SR+
BIAS SR-
D
40
03
N
S
R
10
20
D
40
12
N
S
R
10
20
-14V
+14V
D4004
NSR1020
+14V
50V
C4007
100N
AGND
50V
C4012
100N
5V6
DZ4000
BZX84C
0W125
R4041
220K
AGND
+14V
-14V
50V
C4037
100N
5V6
DZ4003
BZX84C
25
V
C
40
35
1U
F
25
V
C
40
13
1U
F
-14V
+14V
AGND
AGND
P4083
+SR Input
+SR Input
5
3
4
TR
40
10
B
B
C
84
6B
D
2
6
1
TR
40
10
A
B
C
84
6B
D
2
6
1
TR
40
12
A
B
C
84
6B
D
5
3
4
TR
40
12
B
B
C
84
6B
D
2
6
1
TR
40
22
A
B
C
84
6B
D
2
6
1
TR
40
20
A
B
C
84
6B
D
4
3
5
TR
40
04
A
B
C
85
6B
D
4
3
5
TR
40
07
A
B
C
85
6B
D
1
6
2
TR
40
16
B
B
C
85
6B
D
4
3
5
TR
40
16
A
B
C
85
6B
D
4
3
5
TR
40
19
A
B
C
85
6B
D
1
6
2
TR
40
19
B
B
C
85
6B
D
1
6
2
TR
40
04
B
B
C
85
6B
D
5
3
4
TR4020B
BC846BD
5
3
4
TR
40
22
B
B
C
84
6B
D
1
6
2
TR4007B
BC856BD
100V
C4009
1N0
AGND
-14V
AGND
0W
12
5
R
40
99
22
0K
AGND
TR4017
KSC3503
TR4011
KSA1381
GND_C
P
40
09
P4007
0W25
R4005
68R
GND_C
P
41
19
P
41
20
P
41
17
0W25
R4117
68R
TR4009
BC846B
TR4008
BC856B
TR4015
BC846B
TR4013
BC856B
50V
C4021
10UF
50V
C4018
10UF
0W25
R4036
12K
0W25
R4088
12K
0W
25
R
40
34
12
K
0W
25
R
40
90
12
K
D4005
BAS21LT1
D4009
BAS21LT1
P4082
P4081
P
40
87
P
40
33
P4034
P4051
P4069
P4045
P4075
P4070
P4053
P4052
P4071
P4038
P4084
27V
DZ4001
GLZ
27V
DZ4002
GLZ
D
40
07
B
A
V
19
9
D
40
08
B
A
V
19
9
100V
C4002
220UF
100V
C4039
220UF
0W1
0.10%
R4059
1K0
0W1
0.10%
R4089
1K0
50V
C4016
470P
50V
C4026
470P
D4001
NSR1020
D4014
NSR1020
0W
25
R
40
46
68
R
0W
25
R
40
69
68
R
N
F
N
F
N
F
50V
C4010
22N
50V
C4029
22N
100V
C4019
150P
100V
C4028
150P
100V
C4017
33P
100V
C4027
33P
D
40
13
N
S
R
10
20
-55V
+55V
R
E
D
LE
D
40
01
06
03
R
E
D
LE
D
40
00
06
03
0W
06
3
R
40
71
68
R
0W
06
3
R
40
72
68
R
0W
06
3
R
40
98
1K
5
0W
06
3
R
40
17
1K
5
0W
06
3
R
40
08
5K
1
0W063
R4003
3M3
0W063
R4012
20K
0W
06
3
R
40
66
15
K
50V
C4015
100N
0W063
R4108
360R
50V
C4038
100N
0W
06
3
R
41
00
4K
7
50V
C4040
1N0
0W
06
3
R
41
14
1K
5
50V
C4031
100N
0W
06
3
R
40
74
1K
5
0W
06
3
R
40
83
68
R
0W
06
3
R
40
84
68
R
0W
06
3
R
40
39
4K
7
0W
12
5
R
40
94
6K
8
0W
12
5
R
40
60
6K
8
0W
06
3
R
41
09
1K
5
0W063
R4107
68R
0W
06
3
R
41
12
1K
0
0W
06
3
R
41
16
47
R
0W063
R4111
100R
100V
C4041
1uF
50
V
C
40
34
1N
0
AGND
0W
06
3
R
40
70
0R
0
0W063
R4057
0R0
0W063
R4058
0R0
0W
06
3
R
40
26
1K
0
0W063
R4032
68R
0W
06
3
R
40
27
47
R
0W125
R4097
10K
0W125
R4040
10K
0W063
R4031
100R
100V
C4006
1uF
AGND
50
V
C
40
11
1N
0
N
F
N
F
0W063
R4015
10R
0W063
R4105
10R
0W
06
3
R
40
48
22
0R
N
F
0W063
R4016
10R
0W063
R4106
10R
100V
C4036
220N
100V
C4004
220N
0W
06
3
R
40
29
22
0R
0W
06
3
R
40
93
22
0R
0W063
R4101
3K3
0W063
R4019
3K3
0W063
R4047
0R0
0W063
R4050
0R0
0W063
R4033
1K0
0W063
R4085
1K0
0W
06
3
R
40
44
43
0R
0W
06
3
R
40
76
43
0R
0W
06
3
R
40
45
2K
7
0W
06
3
R
40
77
2K
7
0W
06
3
R
40
01
10
K
0W063
R4000
4K7
0W063
R4038
330R
0W063
R4079
330R
0W
25
R
40
67
2K
7
0W
25
R
40
80
2K
7
0W
06
3
R
40
25
1K
5
0W
06
3
R
40
95
20
R
TH
40
01
10
0R
@
25
C
TH
40
00
47
k@
25
C
TH
40
02
47
k@
25
C
N
F
NF
N
F
NF
N
F
N
F
NF
0W5
R4024
0R47
0W5
R4023
0R47
1W
R4102
47R
1W
R4006
47R
1W
R
40
37
1K
5
1W
R
40
91
1K
5
2W
R
40
75
3R
3
AGND
Op Amp Decoupling
50V
C4044
100N
50V
C4047
100N
+14V
-14V
100V
C4003
22P
TR4006A
NJL3281DG
TR
40
06
B
N
JL
32
81
D
G
AGND
0W063
R4002
1K0
0W063
R4007
1K0
P4124
P4011
P4012
P4112
P4122
P4123
P4125
P4131
P4128
P4062
P4127
P4129
P4126
P4132
P4133
P4130
P4105
P4121
P4002
P
41
10
P
40
22
PLD
PLD
P
40
21
TR4025
MMBTA42L
+55V
0W125
R4103
47K
-55V
0W063
R4020
47R
D4002
BAS21HT1G
P
41
06
NLD
NLD
TR
40
26
M
M
B
TA
92
L
0W125
R4118
47K
-55V
+55V
0W063
R4104
47R
D4011
BAS21HT1G
50V
C4023
22UF
2
3
1
8
4
IC4001A
LM4562MA
6
5
7
IC4001B
LM4562MA
0W125
Thin Film
R4013
15K
0W125
Thin Film
R4014
15K
0W
06
3
R
40
21
27
0R
0W
06
3
R
40
22
3K
3
100V
C4022
22P
100V
C4025
22P
0W
06
3
R
40
81
18
0R
0W
06
3
R
40
49
10
R
18_E048
PK
28/11/18
F.0
Amplifier improvements
0W063
R4113
360R
19_E007
JH
11/02/2019
G.0
Rx113 changed to 360R
0W
06
3
R
40
18
6K
8
0W
06
3
R
41
15
6K
8
0W125
Thin Film
R4010
10K
0W
12
5
R
40
82
22
0K
0W
06
3
R
40
51
4R
7
0W
06
3
R
40
61
4R
7
0W
06
3
R
40
52
33
0R
0W
06
3
R
40
62
33
0R
0W125
R4092
4R7
19_E027
PK
20/05/19
1.0
Value changes protection and compensation
0W
1
0.
10
%
R
40
09
30
K
0W1
0.10%
R4056
3K0
0W1
0.10%
R4087
3K0
0W1 0.10%
R4042
2K0
0W1 0.10%
R4078
2K0
20_E002
PK
06/01/20
2.0
PCB change only
21_E001
PK
12/01/21
3.0
No change to this sheet
Summary of Contents for HDA PA720
Page 1: ...SERVICE MANUAL POWER AMPLIFIER PA720 ISSUE A ...
Page 2: ...EN 2 Revision History Issue A Initial release ...
Page 14: ...EN 14 EN 14 L281 Power Amplifier PCB Issue 3 ...
Page 36: ...EN 36 EN 36 L282 Pre amp PCB Issue 2 ...
Page 50: ...EN 50 EN 50 L283 PSU PCB Issue 1 ...
Page 54: ...EN 54 L284 Lifter PCB Issue 1 ...
Page 59: ...EN 59 L285 Front Panel PCB Issue 1 ...
Page 62: ...EN 62 Overall Dimensions ...
Page 64: ...EN 64 Exploded Drawings ...