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EN-29
ISSUE
DRAWING NO.
DRAWING TITLE
DATE
Filename:
ECO No.
DESCRIPTION OF CHANGE
L281 CT4 SL Channel.SchDoc
AMP019 Amp SL
Contact Engineer:
L281CT
15/01/2021
INITIALS
Printed:
4
10
Sheet
of
Notes:
Contact Tel:
01223 203201
Jon Henderson
A & R Cambridge Ltd.
Cambridge CB25 9QE
Waterbeach
A3
ARCAM
LIN
RV3000
1K
AGND
AGND
TR3005
BC856B
10
0V
C
30
14
82
P
AGND
TR3023
BC846B
10
0V
C
30
30
82
P
TR3002
2SC2690A
TR3021
KSA1220A
TR3001
MMBTA42L
TR
30
24
M
M
B
TA
92
L
0W
12
5
R
30
28
33
R
0W
12
5
R
30
96
33
R
0W
12
5
R
30
43
56
0R
0W
12
5
R
30
73
56
0R
0W125
R3030
10R
0W
12
5
R
31
10
22
R
0W
12
5
R
30
11
22
R
GND_B
GND_B
TR3003
2SC2690A
TR3018
KSA1220A
D
30
06
S
1D
D
30
10
S
1D
63V
C3008
22UF
63V
C3033
22UF
100V
C3005
1uF
GND_A
100V
C3032
1uF
GND_A
+VLIFT
-VLIFT
2W
R
30
55
0.18R
2W
R
30
65
0.18R
2W
R
30
64
0.18R
2W
R
30
54
0.18R
2W
R
30
53
0.18R
2W
R
30
63
0.18R
+Input SL
-Input SL
0W5
R3035
1R0
6
5
7
IC1000B
OPA1652AIDR
AGND
0W063
R3004
10K
AGND
D3000
BAV99
ERR +VE
ERR -VE
100V
C3001
470N
20C/W
HS3000A
5400-9130+0
20C/W
HS3001A
5400-9130+0
TR3014A
NJL1302DG
TR
30
14
B
N
JL
13
02
D
G
0W5
R3086
1R0
0W
12
5
R
30
68
10
0K
1206
FS3000
7.0A
1206
FS3001
7.0A
GND_SL
1
2
8mm
J3000
LINK
1
2
8mm
J3002
LINK
1
2
8mm
J3003
LINK
1
2
8mm
J3004
LINK
1
2
8mm
J3005
LINK
1
2
8mm
J3007
LINK
1
2
8mm
J3001
LINK
1
2
8mm
J3006
LINK
-SL Input
NF
AGND
P
30
65
P3059
P3074
P3066
P3067
P3055
P3041
P3017
P3047
P3064
P
30
92
P3044
P3029
P3060
P
30
32
P
30
42
P3026
P3048
P
30
24
P3046
P3099
P3061
P3100
P3080
P3079
P3073
P3105
P3096
P3109
P3115
P3114
P3107
P3108
P3098
P3116
P
31
18
P3005
P3006
P3001
P3004
P
30
10
P
30
16
P3062
P3063
P3078
P3111
P3015
P3023
P3037
P3020
P
30
18
P3013
P3014
P3019
P3028
P3049
P3030
P3025
P3057
P3027
P3031
P3040
P3043
P
30
50
P
30
72
P3076
P3090
P
30
89
P3085
P3088
P3036
P3039
P3054
P3095
P3091
P3103
P3102
P3086
P3094
P3101
P3077
P
31
10
P3113
P3112
P3097
P3068
P
31
04
P3058
P3093
10
0V
C
30
24
10
0N
100V
C3020
100N
FILM
-SL Input
Out SL
Out SL
1
2
M20-973
CON3000
HARWIN
SHORT SL
SHORT SL
TR3000
MMBTA42L
25V
C3000
1uF
P3000
P3003
P3008
Bias measurement
ERR +VE
ERR -VE
BIAS SL+
BIAS SL-
BIAS SL+
BIAS SL-
D
30
03
N
S
R
10
20
D
30
12
N
S
R
10
20
-14V
+14V
D3004
NSR1020
+14V
50V
C3007
100N
AGND
50V
C3012
100N
5V6
DZ3000
BZX84C
0W125
R3041
220K
AGND
+14V
-14V
50V
C3037
100N
5V6
DZ3003
BZX84C
25
V
C
30
35
1U
F
25
V
C
30
13
1U
F
-14V
+14V
AGND
AGND
P3083
+SL Input
+SL Input
5
3
4
TR
30
10
B
B
C
84
6B
D
2
6
1
TR
30
10
A
B
C
84
6B
D
2
6
1
TR
30
12
A
B
C
84
6B
D
5
3
4
TR
30
12
B
B
C
84
6B
D
2
6
1
TR
30
22
A
B
C
84
6B
D
2
6
1
TR
30
20
A
B
C
84
6B
D
4
3
5
TR
30
04
A
B
C
85
6B
D
4
3
5
TR
30
07
A
B
C
85
6B
D
1
6
2
TR
30
16
B
B
C
85
6B
D
4
3
5
TR
30
16
A
B
C
85
6B
D
4
3
5
TR
30
19
A
B
C
85
6B
D
1
6
2
TR
30
19
B
B
C
85
6B
D
1
6
2
TR3004B
BC856BD
5
3
4
TR3020B
BC846BD
5
3
4
TR
30
22
B
B
C
84
6B
D
1
6
2
TR3007B
BC856BD
100V
C3009
1N0
AGND
-14V
AGND
0W
12
5
R
30
99
22
0K
AGND
TR3017
KSC3503
TR3011
KSA1381
GND_C
P
30
09
P3007
0W25
R3005
68R
GND_C
P
31
19
P
31
20
P
31
17
0W25
R3117
68R
TR3009
BC846B
TR3008
BC856B
TR3015
BC846B
TR3013
BC856B
50V
C3021
10UF
50V
C3018
10UF
0W25
R3036
12K
0W25
R3088
12K
0W
25
R
30
34
12
K
0W
25
R
30
90
12
K
D3005
BAS21LT1
D3009
BAS21LT1
P3082
P3081
P
30
87
P
30
33
P3034
P3051
P3069
P3045
P3075
P3070
P3053
P3052
P3071
P3038
P3084
27V
DZ3001
GLZ
27V
DZ3002
GLZ
D
30
07
B
A
V
19
9
D
30
08
B
A
V
19
9
100V
C3002
220UF
100V
C3039
220UF
0W1
0.10%
R3059
1K0
0W1
0.10%
R3089
1K0
50V
C3016
470P
50V
C3026
470P
D3001
NSR1020
D3014
NSR1020
0W
25
R
30
46
68
R
0W
25
R
30
69
68
R
N
F
N
F
N
F
50V
C3010
22N
50V
C3029
22N
100V
C3019
150P
100V
C3028
150P
100V
C3017
33P
100V
C3027
33P
D
30
13
N
S
R
10
20
-55V
+55V
R
E
D
LE
D
30
01
06
03
R
E
D
LE
D
30
00
06
03
0W
06
3
R
30
71
68
R
0W
06
3
R
30
72
68
R
0W
06
3
R
30
98
1K
5
0W
06
3
R
30
17
1K
5
0W
06
3
R
30
08
5K
1
0W063
R3003
3M3
0W063
R3012
20K
0W
06
3
R
30
66
15
K
50V
C3015
100N
0W063
R3108
360R
50V
C3038
100N
0W
06
3
R
31
00
4K
7
50V
C3040
1N0
0W
06
3
R
31
14
1K
5
50V
C3031
100N
0W
06
3
R
30
74
1K
5
0W
06
3
R
30
83
68
R
0W
06
3
R
30
84
68
R
0W
06
3
R
30
39
4K
7
0W
12
5
R
30
94
6K
8
0W
12
5
R
30
60
6K
8
0W
06
3
R
31
09
1K
5
0W063
R3107
68R
0W
06
3
R
31
12
1K
0
0W
06
3
R
31
16
47
R
0W063
R3111
100R
100V
C3041
1uF
50
V
C
30
34
1N
0
AGND
0W
06
3
R
30
70
0R
0
0W063
R3057
0R0
0W063
R3058
0R0
0W
06
3
R
30
26
1K
0
0W063
R3032
68R
0W
06
3
R
30
27
47
R
0W125
R3097
10K
0W125
R3040
10K
0W063
R3031
100R
100V
C3006
1uF
AGND
50
V
C
30
11
1N
0
N
F
N
F
0W063
R3015
10R
0W063
R3105
10R
0W
06
3
R
30
48
22
0R
N
F
0W063
R3016
10R
0W063
R3106
10R
100V
C3036
220N
100V
C3004
220N
0W
06
3
R
30
29
22
0R
0W
06
3
R
30
93
22
0R
0W063
R3101
3K3
0W063
R3019
3K3
0W063
R3047
0R0
0W063
R3050
0R0
0W063
R3033
1K0
0W063
R3085
1K0
0W
06
3
R
30
44
43
0R
0W
06
3
R
30
76
43
0R
0W
06
3
R
30
45
2K
7
0W
06
3
R
30
77
2K
7
0W
06
3
R
30
01
10
K
0W063
R3000
4K7
0W063
R3038
330R
0W063
R3079
330R
0W
25
R
30
67
2K
7
0W
25
R
30
80
2K
7
0W
06
3
R
30
25
1K
5
0W
06
3
R
30
95
20
R
TH
30
01
10
0R
@
25
C
TH
30
00
47
k@
25
C
TH
30
02
47
k@
25
C
N
F
NF
N
F
NF
N
F
N
F
NF
AGND
Op Amp Decoupling
50V
C3043
100N
50V
C3046
100N
+14V
-14V
0W5
R3023
0R47
0W5
R3024
0R47
1W
R3102
47R
1W
R3006
47R
1W
R
30
37
1K
5
1W
R
30
91
1K
5
2W
R
30
75
3R
3
100V
C3003
22P
TR3006A
NJL3281DG
TR
30
06
B
N
JL
32
81
D
G
AGND
0W063
R3002
1K0
0W063
R3007
1K0
P3126
P3002
P3011
P3122
P3124
P3125
P3127
P3130
P3133
P3134
P3135
P3012
P3022
P3121
P3132
P3128
P3131
P3123
P
31
29
P3056
P
30
35
P
31
06
NLD
NLD
TR
30
26
M
M
B
TA
92
L
0W125
R3118
47K
-55V
+55V
0W063
R3104
47R
D3011
BAS21HT1G
PLD
PLD
P
30
21
TR3025
MMBTA42L
+55V
0W125
R3103
47K
-55V
0W063
R3020
47R
D3002
BAS21HT1G
50V
C3023
22UF
2
3
1
8
4
IC3001A
LM4562MA
6
5
7
IC3001B
LM4562MA
0W125
Thin Film
R3013
15K
0W125
Thin Film
R3014
15K
0W
06
3
R
30
21
27
0R
0W
06
3
R
30
22
3K
3
100V
C3022
22P
100V
C3025
22P
0W
06
3
R
30
81
18
0R
0W
06
3
R
30
49
10
R
18_E048
PK
28/11/18
F.0
Amplifier improvements
0W063
R3113
360R
19_E007
JH
11/02/2019
G.0
Rx113 changed to 360R
0W
06
3
R
30
51
4R
7
0W
06
3
R
30
61
4R
7
0W
06
3
R
30
52
33
0R
0W
06
3
R
30
62
33
0R
0W
12
5
R
30
82
22
0K
0W125
Thin Film
R3010
10K
0W
06
3
R
30
18
6K
8
0W
06
3
R
31
15
6K
8
0W125
R3092
4R7
19_E027
PK
20/05/19
1.0
Value changes protection and compensation
0W
1
0.
10
%
R
30
09
30
K
0W1
0.10%
R3056
3K0
0W1
0.10%
R3087
3K0
0W1 0.10%
R3042
2K0
0W1 0.10%
R3078
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 ...