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EN-28
ISSUE
DRAWING NO.
DRAWING TITLE
DATE
Filename:
ECO No.
DESCRIPTION OF CHANGE
L281 CT3 R Channel.SchDoc
AMP019 Amp R
Contact Engineer:
L281CT
15/01/2021
INITIALS
Printed:
3
10
Sheet
of
Notes:
Contact Tel:
01223 203201
Jon Henderson
A & R Cambridge Ltd.
Cambridge CB25 9QE
Waterbeach
A3
ARCAM
LIN
RV2000
1K
AGND
AGND
TR2005
BC856B
10
0V
C
20
14
82
P
AGND
TR2023
BC846B
10
0V
C
20
30
82
P
TR2002
2SC2690A
TR2021
KSA1220A
TR2001
MMBTA42L
TR
20
24
M
M
B
TA
92
L
0W
12
5
R
20
28
33
R
0W
12
5
R
20
96
33
R
0W
12
5
R
20
43
56
0R
0W
12
5
R
20
73
56
0R
0W125
R2030
10R
0W
12
5
R
21
10
22
R
0W
12
5
R
20
11
22
R
GND_B
GND_B
TR2003
2SC2690A
TR2018
KSA1220A
D
20
06
S
1D
D
20
10
S
1D
63V
C2008
22UF
63V
C2033
22UF
100V
C2005
1uF
GND_A
100V
C2032
1uF
GND_A
+VLIFT
-VLIFT
2W
R
20
55
0.18R
2W
R
20
65
0.18R
2W
R
20
64
0.18R
2W
R
20
54
0.18R
2W
R
20
53
0.18R
2W
R
20
63
0.18R
+Input R
-Input R
0W5
R2035
1R0
2
3
1
8
4
IC2000A
OPA1652AIDR
AGND
-14V
+14V
0W063
R2004
10K
AGND
D2000
BAV99
ERR +VE
ERR -VE
100V
C2001
470N
20C/W
HS2000A
5400-9130+0
20C/W
HS2001A
5400-9130+0
TR2014A
NJL1302DG
TR
20
14
B
N
JL
13
02
D
G
0W5
R2086
1R0
0W
12
5
R
20
68
10
0K
1206
FS2000
7.0A
1206
FS2001
7.0A
GND_R
1
2
8mm
J2000
LINK
1
2
8mm
J2002
LINK
1
2
8mm
J2003
LINK
1
2
8mm
J2004
LINK
1
2
8mm
J2005
LINK
1
2
8mm
J2007
LINK
1
2
8mm
J2001
LINK
1
2
8mm
J2006
LINK
-R Input
NF
AGND
P
20
65
P2059
P2074
P2066
P2067
P2055
P2056
P2035
P2041
P2017
P2047
P2064
P
20
92
P2044
P2029
P2060
P
20
32
P
20
42
P2026
P2048
P
20
24
P2046
P2099
P2061
P2100
P2080
P2079
P2073
P2105
P2096
P2109
P2115
P2114
P2107
P2108
P2098
P2116
P
21
18
P2002
P2011
P2005
P2006
P2001
P2004
P
20
10
P
20
16
P2063
P2078
P2015
P2023
P2037
P2020
P
20
18
P2013
P2014
P2019
P2028
P2049
P2030
P2025
P2057
P2027
P2031
P2040
P2043
P
20
50
P
20
72
P2076
P2090
P
20
89
P2085
P2088
P2036
P2039
P2054
P2095
P2091
P2103
P2102
P2086
P2094
P2101
P2077
P
21
10
P2113
P2112
P2097
P2068
P
21
04
P2058
P2093
10
0V
C
20
24
10
0N
100V
C2020
100N
FILM
-R Input
Out R
Out R
1
2
M20-973
CON2000
HARWIN
SHORT R
SHORT R
TR2000
MMBTA42L
25V
C2000
1uF
P2000
P2003
P2008
Bias measurement
ERR +VE
ERR -VE
BIAS R+
BIAS R-
BIAS R+
BIAS R-
D
20
03
N
S
R
10
20
D
20
12
N
S
R
10
20
-14V
+14V
D2004
NSR1020
+14V
50V
C2007
100N
AGND
50V
C2012
100N
5V6
DZ2000
BZX84C
0W125
R2041
220K
AGND
+14V
-14V
50V
C2037
100N
5V6
DZ2003
BZX84C
25
V
C
20
35
1U
F
25
V
C
20
13
1U
F
-14V
+14V
AGND
AGND
P2083
+R Input
+R Input
5
3
4
TR
20
10
B
B
C
84
6B
D
2
6
1
TR
20
10
A
B
C
84
6B
D
2
6
1
TR
20
12
A
B
C
84
6B
D
5
3
4
TR
20
12
B
B
C
84
6B
D
2
6
1
TR
20
22
A
B
C
84
6B
D
2
6
1
TR
20
20
A
B
C
84
6B
D
4
3
5
TR
20
04
A
B
C
85
6B
D
4
3
5
TR
20
07
A
B
C
85
6B
D
1
6
2
TR
20
16
B
B
C
85
6B
D
4
3
5
TR
20
16
A
B
C
85
6B
D
4
3
5
TR
20
19
A
B
C
85
6B
D
1
6
2
TR
20
19
B
B
C
85
6B
D
1
6
2
TR
20
04
B
B
C
85
6B
D
5
3
4
TR2020B
BC846BD
5
3
4
TR
20
22
B
B
C
84
6B
D
1
6
2
TR2007B
BC856BD
100V
C2009
1N0
AGND
-14V
AGND
0W
12
5
R
20
99
22
0K
AGND
TR2017
KSC3503
TR2011
KSA1381
GND_C
P
20
09
P2007
0W25
R2005
68R
GND_C
P
21
19
P
21
20
P
21
17
0W25
R2117
68R
TR2009
BC846B
TR2008
BC856B
TR2015
BC846B
TR2013
BC856B
50V
C2021
10UF
50V
C2018
10UF
0W25
R2036
12K
0W25
R2088
12K
0W
25
R
20
34
12
K
0W
25
R
20
90
12
K
D2005
BAS21LT1
D2009
BAS21LT1
P2082
P
20
87
P
20
33
P2034
P2051
P2069
P2045
P2075
P2070
P2053
P2052
P2071
P2038
P2084
27V
DZ2001
GLZ
27V
DZ2002
GLZ
D
20
07
B
A
V
19
9
D
20
08
B
A
V
19
9
100V
C2002
220UF
100V
C2039
220UF
0W1
0.10%
R2059
1K0
0W1
0.10%
R2089
1K0
50V
C2016
470P
50V
C2026
470P
D2001
NSR1020
D2014
NSR1020
0W
25
R
20
46
68
R
0W
25
R
20
69
68
R
N
F
N
F
N
F
50V
C2010
22N
50V
C2029
22N
100V
C2019
150P
100V
C2028
150P
100V
C2017
33P
100V
C2027
33P
D
20
13
N
S
R
10
20
-55V
+55V
R
E
D
LE
D
20
01
06
03
R
E
D
LE
D
20
00
06
03
0W
06
3
R
20
71
68
R
0W
06
3
R
20
72
68
R
0W
06
3
R
20
98
1K
5
0W
06
3
R
20
17
1K
5
0W
06
3
R
20
08
5K
1
0W063
R2003
3M3
0W063
R2012
20K
0W
06
3
R
20
66
15
K
50V
C2015
100N
0W063
R2108
360R
50V
C2038
100N
0W
06
3
R
21
00
4K
7
50V
C2040
1N0
0W
06
3
R
21
14
1K
5
50V
C2031
100N
0W
06
3
R
20
74
1K
5
0W
06
3
R
20
83
68
R
0W
06
3
R
20
84
68
R
0W
06
3
R
20
39
4K
7
0W
12
5
R
20
94
6K
8
0W
12
5
R
20
60
6K
8
0W
06
3
R
21
09
1K
5
0W063
R2107
68R
0W
06
3
R
21
12
1K
0
0W
06
3
R
21
16
47
R
0W063
R2111
100R
100V
C2041
1uF
50
V
C
20
34
1N
0
AGND
0W
06
3
R
20
70
0R
0
0W063
R2057
0R0
0W063
R2058
0R0
0W
06
3
R
20
26
1K
0
0W063
R2032
68R
0W
06
3
R
20
27
47
R
0W125
R2097
10K
0W125
R2040
10K
0W063
R2031
100R
100V
C2006
1uF
AGND
50
V
C
20
11
1N
0
N
F
N
F
0W063
R2015
10R
0W063
R2105
10R
0W
06
3
R
20
48
22
0R
N
F
0W063
R2016
10R
0W063
R2106
10R
100V
C2036
220N
100V
C2004
220N
0W
06
3
R
20
29
22
0R
0W
06
3
R
20
93
22
0R
0W063
R2101
3K3
0W063
R2019
3K3
0W063
R2047
0R0
0W063
R2050
0R0
0W063
R2033
1K0
0W063
R2085
1K0
0W
06
3
R
20
44
43
0R
0W
06
3
R
20
76
43
0R
0W
06
3
R
20
45
2K
7
0W
06
3
R
20
77
2K
7
0W
06
3
R
20
01
10
K
0W063
R2000
4K7
0W063
R2038
330R
0W063
R2079
330R
0W
25
R
20
67
2K
7
0W
25
R
20
80
2K
7
0W
06
3
R
20
25
1K
5
0W
06
3
R
20
95
20
R
TH
20
01
10
0R
@
25
C
TH
20
00
47
k@
25
C
TH
20
02
47
k@
25
C
N
F
NF
N
F
NF
N
F
N
F
NF
0W5
R2024
0R47
0W5
R2023
0R47
1W
R2006
47R
1W
R2102
47R
1W
R
20
37
1K
5
1W
R
20
91
1K
5
2W
R
20
75
3R
3
AGND
Op Amp Decoupling
50V
C2043
100N
50V
C2044
100N
50V
C2046
100N
50V
C2047
100N
50V
C2042
10UF
50V
C2045
10UF
+14V
-14V
100V
C2003
22P
TR2006A
NJL3281DG
TR
20
06
B
N
JL
32
81
D
G
AGND
0W063
R2002
1K0
0W063
R2007
1K0
P2126
P2012
P2022
P2122
P2124
P2125
P2127
P2130
P2133
P2062
P2111
P2135
P2121
P2129
P2132
P2131
P2123
P2128
P
20
81
P
21
34
P
21
06
NLD
NLD
TR
20
26
M
M
B
TA
92
L
0W125
R2118
47K
-55V
+55V
0W063
R2104
47R
D2011
BAS21HT1G
PLD
PLD
P
20
21
TR2025
MMBTA42L
+55V
0W125
R2103
47K
-55V
0W063
R2020
47R
D2002
BAS21HT1G
50V
C2023
22UF
2
3
1
8
4
IC2001A
LM4562MA
6
5
7
IC2001B
LM4562MA
0W125
Thin Film
R2013
15K
0W125
Thin Film
R2014
15K
0W
06
3
R
20
21
27
0R
0W
06
3
R
20
22
3K
3
100V
C2022
22P
100V
C2025
22P
0W
06
3
R
20
81
18
0R
0W
06
3
R
20
49
10
R
18_E048
PK
28/11/18
F.0
Amplifier improvements
0W063
R2113
360R
19_E007
JH
11/02/2019
G.0
Rx113 changed to 360R, Schottky error actually fixed
0W
06
3
R
20
18
6K
8
0W
06
3
R
21
15
6K
8
0W
12
5
R
20
82
22
0K
0W125
Thin Film
R2010
10K
0W
06
3
R
20
51
4R
7
0W
06
3
R
20
61
4R
7
0W
06
3
R
20
52
33
0R
0W
06
3
R
20
62
33
0R
0W125
R2092
4R7
19_E027
PK
20/05/19
1.0
Value changes protection and compensation
0W
1
0.
10
%
R
20
09
30
K
0W1
0.10%
R2056
3K0
0W1
0.10%
R2087
3K0
0W1 0.10%
R2042
2K0
0W1 0.10%
R2078
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 ...