EN-31
ISSUE
DRAWING NO.
DRAWING TITLE
DATE
Filename:
ECO No.
DESCRIPTION OF CHANGE
L281 CT6 BL Channel.SchDoc
AMP019 Amp BL
Contact Engineer:
L281CT
15/01/2021
INITIALS
Printed:
6
10
Sheet
of
Notes:
Contact Tel:
01223 203201
Jon Henderson
A & R Cambridge Ltd.
Cambridge CB25 9QE
Waterbeach
A3
ARCAM
AGND
Op Amp Decoupling
50V
C5043
100N
50V
C5044
100N
50V
C5046
100N
50V
C5047
100N
50V
C5042
10UF
50V
C5045
10UF
+14V
-14V
P5121
LIN
RV5000
1K
AGND
AGND
TR5005
BC856B
10
0V
C
50
14
82
P
AGND
TR5023
BC846B
10
0V
C
50
30
82
P
TR5002
2SC2690A
TR5021
KSA1220A
TR5001
MMBTA42L
TR
50
24
M
M
B
TA
92
L
0W
12
5
R
50
28
33
R
0W
12
5
R
50
96
33
R
0W
12
5
R
50
43
56
0R
0W
12
5
R
50
73
56
0R
0W125
R5030
10R
0W
12
5
R
51
10
22
R
0W
12
5
R
50
11
22
R
GND_B
GND_B
TR5003
2SC2690A
TR5018
KSA1220A
D
50
06
S
1D
D
50
10
S
1D
63V
C5008
22UF
63V
C5033
22UF
100V
C5005
1uF
GND_A
100V
C5032
1uF
GND_A
+VLIFT
-VLIFT
2W
R
50
55
0.18R
2W
R
50
65
0.18R
2W
R
50
64
0.18R
2W
R
50
54
0.18R
2W
R
50
53
0.18R
2W
R
50
63
0.18R
+Input BL
-Input BL
0W5
R5035
1R0
2
3
1
8
4
IC5000A
OPA1652AIDR
AGND
-14V
+14V
0W063
R5004
10K
AGND
D5000
BAV99
ERR +VE
ERR -VE
100V
C5001
470N
20C/W
HS5000A
5400-9130+0
20C/W
HS5001A
5400-9130+0
TR5014A
NJL1302DG
TR
50
14
B
N
JL
13
02
D
G
0W5
R5086
1R0
2W
R
50
75
3R
3
0W
12
5
R
50
68
10
0K
1206
FS5000
7.0A
1206
FS5001
7.0A
GND_BL
1
2
8mm
J5000
LINK
1
2
8mm
J5002
LINK
1
2
8mm
J5003
LINK
1
2
8mm
J5004
LINK
1
2
8mm
J5005
LINK
1
2
8mm
J5007
LINK
1
2
8mm
J5001
LINK
1
2
8mm
J5006
LINK
-BL Input
NF
AGND
P
50
65
P5059
P5074
P5066
P5067
P5055
P5056
P5041
P5017
P5047
P5064
P
50
92
P5044
P5029
P5060
P
50
32
P
50
42
P5026
P5048
P
50
24
P5046
P5099
P5061
P5100
P5080
P5079
P5073
P5105
P5096
P5109
P5115
P5114
P5107
P5108
P5098
P5116
P
51
18
P5002
P5011
P5005
P5006
P5001
P5004
P
50
10
P
50
16
P5063
P5078
P5015
P5023
P5037
P5020
P
50
18
P5013
P5014
P5019
P5028
P5049
P5030
P5025
P5057
P5027
P5022
P5031
P5040
P5043
P
50
50
P
50
72
P5076
P5090
P
50
89
P5085
P5088
P5036
P5039
P5054
P5095
P5091
P5103
P5102
P5086
P5094
P5101
P5077
P
51
10
P5113
P5097
P5068
P
51
04
P5058
P5093
10
0V
C
50
24
10
0N
100V
C5020
100N
FILM
-BL Input
Out BL
Out BL
1
2
M20-973
CON5000
HARWIN
SHORT BL
SHORT BL
TR5000
MMBTA42L
25V
C5000
1uF
P5000
P5003
P5008
Bias measurement
ERR +VE
ERR -VE
BIAS BL+
BIAS BL-
BIAS BL+
BIAS BL-
D
50
03
N
S
R
10
20
D
50
12
N
S
R
10
20
-14V
+14V
D5004
NSR1020
+14V
50V
C5007
100N
AGND
50V
C5012
100N
5V6
DZ5000
BZX84C
0W125
R5041
220K
AGND
+14V
-14V
50V
C5037
100N
5V6
DZ5003
BZX84C
25
V
C
50
35
1U
F
25
V
C
50
13
1U
F
-14V
+14V
AGND
AGND
P5083
+BL Input
+BL Input
5
3
4
TR
50
10
B
B
C
84
6B
D
2
6
1
TR
50
10
A
B
C
84
6B
D
2
6
1
TR
50
12
A
B
C
84
6B
D
5
3
4
TR
50
12
B
B
C
84
6B
D
2
6
1
TR
50
22
A
B
C
84
6B
D
2
6
1
TR
50
20
A
B
C
84
6B
D
4
3
5
TR
50
04
A
B
C
85
6B
D
4
3
5
TR
50
07
A
B
C
85
6B
D
1
6
2
TR
50
16
B
B
C
85
6B
D
4
3
5
TR
50
16
A
B
C
85
6B
D
4
3
5
TR
50
19
A
B
C
85
6B
D
1
6
2
TR
50
19
B
B
C
85
6B
D
1
6
2
TR
50
04
B
B
C
85
6B
D
5
3
4
TR5020B
BC846BD
5
3
4
TR
50
22
B
B
C
84
6B
D
1
6
2
TR5007B
BC856BD
100V
C5009
1N0
AGND
-14V
AGND
0W
12
5
R
50
99
22
0K
AGND
TR5017
KSC3503
TR5011
KSA1381
GND_C
P
50
09
P5007
P5012
0W25
R5005
68R
PLD
PLD
P
50
21
GND_C
P
51
19
P
51
20
P
51
17
0W25
R5117
68R
P
51
06
TR5009
BC846B
TR5008
BC856B
TR5015
BC846B
TR5013
BC856B
50V
C5021
10UF
50V
C5018
10UF
0W25
R5036
12K
0W25
R5088
12K
0W
25
R
50
34
12
K
0W
25
R
50
90
12
K
D5005
BAS21LT1
D5009
BAS21LT1
P5082
P5081
P
50
87
P
50
33
P5034
P5051
P5069
P5045
P5075
P5070
P5053
P5052
P5071
P5038
P5084
27V
DZ5001
GLZ
27V
DZ5002
GLZ
D
50
07
B
A
V
19
9
D
50
08
B
A
V
19
9
100V
C5002
220UF
100V
C5039
220UF
0W1
0.10%
R5059
1K0
0W1
0.10%
R5089
1K0
50V
C5016
470P
50V
C5026
470P
D5001
NSR1020
D5014
NSR1020
0W
25
R
50
46
68
R
0W
25
R
50
69
68
R
N
F
N
F
N
F
50V
C5010
22N
50V
C5029
22N
100V
C5019
150P
100V
C5028
150P
100V
C5017
33P
100V
C5027
33P
D
50
13
N
S
R
10
20
-55V
+55V
R
E
D
LE
D
50
01
06
03
R
E
D
LE
D
50
00
06
03
0W
06
3
R
50
71
68
R
0W
06
3
R
50
72
68
R
0W
06
3
R
50
98
1K
5
0W
06
3
R
50
17
1K
5
0W
06
3
R
50
08
5K
1
0W063
R5003
3M3
0W063
R5012
20K
0W
06
3
R
50
66
15
K
50V
C5015
100N
0W063
R5108
360R
50V
C5038
100N
0W
06
3
R
51
00
4K
7
50V
C5040
1N0
0W
06
3
R
51
14
1K
5
50V
C5031
100N
0W
06
3
R
50
74
1K
5
0W
06
3
R
50
83
68
R
0W
06
3
R
50
84
68
R
0W
06
3
R
50
39
4K
7
0W
12
5
R
50
94
6K
8
0W
12
5
R
50
60
6K
8
0W
06
3
R
51
09
1K
5
0W063
R5107
68R
0W
06
3
R
51
12
1K
0
0W
06
3
R
51
16
47
R
0W063
R5111
100R
100V
C5041
1uF
50
V
C
50
34
1N
0
AGND
0W
06
3
R
50
70
0R
0
0W063
R5057
0R0
0W063
R5058
0R0
0W
06
3
R
50
26
1K
0
0W063
R5032
68R
0W
06
3
R
50
27
47
R
0W125
R5097
10K
0W125
R5040
10K
0W063
R5031
100R
100V
C5006
1uF
AGND
50
V
C
50
11
1N
0
N
F
N
F
0W063
R5015
10R
0W063
R5105
10R
0W
06
3
R
50
48
22
0R
NF
0W063
R5016
10R
0W063
R5106
10R
100V
C5036
220N
100V
C5004
220N
0W
06
3
R
50
29
22
0R
0W
06
3
R
50
93
22
0R
0W063
R5101
3K3
0W063
R5019
3K3
0W063
R5047
0R0
0W063
R5050
0R0
0W063
R5033
1K0
0W063
R5085
1K0
0W
06
3
R
50
44
43
0R
0W
06
3
R
50
76
43
0R
0W
06
3
R
50
45
2K
7
0W
06
3
R
50
77
2K
7
0W
06
3
R
50
01
10
K
0W063
R5000
4K7
0W063
R5038
330R
0W063
R5079
330R
0W
25
R
50
67
2K
7
0W
25
R
50
80
2K
7
0W
06
3
R
50
25
1K
5
0W
06
3
R
50
95
20
R
TH
50
01
10
0R
@
25
C
TH
50
00
47
k@
25
C
TH
50
02
47
k@
25
C
N
F
NF
N
F
NF
N
F
N
F
NF
0W5
R5024
0R47
0W5
R5023
0R47
1W
R5006
47R
1W
R5102
47R
1W
R
50
37
1K
5
1W
R
50
91
1K
5
6
5
7
IC5000B
OPA1652AIDR
AGND
100V
C5003
22P
TR5006A
NJL3281DG
TR
50
06
B
N
JL
32
81
D
G
AGND
0W063
R5002
1K0
0W063
R5007
1K0
P5129
P5062
P5111
P5112
P5125
P5130
P5127
P5128
P5136
P5133
P5132
P5134
P5135
P5137
P5138
P5131
P5122
P5123
P5124
P5126
P
51
40
P5139
P
50
35
NLD
NLD
TR
50
26
M
M
B
TA
92
L
0W125
R5118
47K
-55V
+55V
TR5025
MMBTA42L
+55V
0W125
R5103
47K
-55V
0W063
R5020
47R
0W063
R5104
47R
D5002
BAS21HT1G
D5011
BAS21HT1G
50V
C5023
22UF
2
3
1
8
4
IC5001A
LM4562MA
6
5
7
IC5001B
LM4562MA
0W125
Thin Film
R5013
15K
0W125
Thin Film
R5014
15K
0W
06
3
R
50
21
27
0R
0W
06
3
R
50
22
3K
3
100V
C5022
22P
100V
C5025
22P
0W
06
3
R
50
81
18
0R
0W
06
3
R
50
49
10
R
18_E048
PK
28/11/18
F.0
Amplifier improvements
0W063
R5113
360R
19_E007
JH
11/02/2019
G.0
Rx113 changed to 360R
NF
NF
NF
NF
0W
06
3
R
50
51
4R
7
0W
06
3
R
50
61
4R
7
0W
06
3
R
50
52
33
0R
0W
06
3
R
50
62
33
0R
0W
12
5
R
50
82
22
0K
0W125
Thin Film
R5010
10K
0W125
R5092
4R7
19_E027
PK
20/05/19
1.0
Value changes protection and compensation
0W
1
0.
10
%
R
50
09
30
K
0W1
0.10%
R5056
3K0
0W1
0.10%
R5087
3K0
0W1 0.10%
R5042
2K0
0W1 0.10%
R5078
2K0
0W
06
3
R
51
15
8K
2
0W
06
3
R
50
18
8K
2
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 ...