Cambridge Audio 840A Service Manual page 33

R2
100R C8 C7
47uF 16V 47uF 35V
Q3
R56
2K2
MPSA93
R4 R5
100R 100R
AMP IN LEFT
JST 2.5MM B2B-XH-A
CN3 C1 Q6
Q5
R27
1
2K2
MPSA93
2
47U 16V
MPSA93
R14
R13
100R
2K2
C15
+48V
4n7 50V COG C6
1000U 10V EL
R78
100K
1N4148
D17
VR2
R80 R81
2
1K 22K
10K P1
D18 C20
PAD
10U NP 16V
1N4148
CHASSIS GND
R79
100K C14
100pF
-48V
Q7
DC OFFSET NULL
Q8
MPSA43 Q11
BC337
MPSA43
R6 R7
68R 68R
+5V
R71
R68 R69
R75
4K7 10K 1M
4K7
U1:B
5
7
6
HI = NORMAL
LM393
TH1
R70
POSITIVE THERMISTOR
1K8
ZPP22 100DEG
850R at 100degC
OVERTEMP DETECT
100deg C cutout
MJE340,350
BC337 MPSA43/93
E B C C B
E C B
3 2 1
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Cambridge Audio Azur 840A Amplifier
R3
D10
68R
1N4148
R72
75K
D11
1N4148
Q4
MPSA93
R17
R57
22K 100R
R10 R12
1K8 18R
R54 R74
D2
R67 16K 2K7
22K 1N4148
Q19
R33
MPSA43
3K6
Q12
MJE340 D14
R52
12V
1K
C9
R11
47uF 16V NFB-L
NFB-L 1K2
R53
D16
1K
VR1
12V
2 Q20
1K
R34
MPSA93
3K3
R55 R76
16K 2K7
D1
1N4148
R23
100R
D23 D24
R73
1N4148
56K
1N4148 D25
C10
1N4148
100pF
Q9
MPSA43
Q10 R50
MPSA43
47K
Q25
R15
MPSA43
R49
22K
16K
R8 R16 R9
R51
2K2 10K 56R
10K
R85 R89
10K 4K7
R91 100R
3
R90
1
2
U1:A
100R
LO = NO SHORT
LM393
C18
100n ceramic D22 D21
100K
R88
R87
1N4002 1N4002
10R
R86
100R
SPEAKER SHORT CIRCUIT TEST SYSTEM
Looking at pins
E
AP16693/5 Power Amplifier Left Channel
R62
R19 R20
D12
150R
0R1 0R1
1N4148
R18
100R
D13
Q13 Q14
1N4148
2SA1295 2SA1295
Q27
Q1
MPSA93
MJE340
R65
R1
47K
10R
R21
0R1
R22
0R1
R64
10K R60 R61
1K1 1K1
R30
470R
Q29
R32 Q28
MPSA93
10R
MPSA93
R63
Q18
1K
Q2
MJE340
MJE350
Q15 Q16
2SC3264
2SC3264
Q26
MPSA43
R58 R59
R25 R26
R24
470R 470R
R66
0R1 0R1
100R
10K
R82
47K
-51V
+5V
Q31
R83
10K LOGIC GND
MPSA93
CN2
XD ON/OFF 1
LOGIC GND
2
+5V
3
+9V
4 1N4148
D19
SPEAKER TEST
SPEAKER TEST 5
CLIP
6
OVERLOAD
7
DC OFFSET
8
OVERTEMP
9
XD ON/OFF
10
MAINS FAIL
11
OUTPUT RELAY A
12
OUTPUT RELAY B
13
PHONES GND
14
MAINS FAIL IN
15
PHONES R
16
PHONES L
FFC 16WAY
PHONES L
PREAMP PCB - LEFT POWER AMP PCB CONN
C4
220uF 80V
PHONES L
R40
220R 3W C
D7
R41
1N5404
470R 1W C
L1 J5
LEFT OUT
1,7U 10A
TERMINAL
R28
J6
R29
2R2 3W
10R 3W TERMINAL
J7 OUTPUT GROUND
TERMINAL
Q17 C2
0u1 POLYESTER
2SA1295
R43
47K
D9
50mW
1N5404
R31
0R68
C5
220uF 80V R42
4K7
+48V
R37
100K
LOGIC GND
1N4148
D5
D4
Q21
MPSA43
1N4148
R35
47K
D3
D20 Q22
MPSA93
CLIP
C3 1N4148
1N4148
22U 50V NP
DC OFFSET
D6
1N4148
CN1
1
+5V LOGIC GND
2 R36
LOGIC GND
3
SPEAKER TEST SENSE 4K7
4
+9V
DC OFFSET DETECT
5
OVERLOAD
6
CLIP
7
OVERTEMP
8
DC OFFSET
9
MAINS FAIL -48V
10
XD ON/OFF
11
OUTPUT RELAY B
12
OUTPUT RELAY A
13
MAINS FAIL IN
14
15
PHONES GND
16
PHONES R
FFC 16WAY
LEFT POWER AMP TO
RIGHT POWER AMP CONNECTOR
+48V
R46
4K7
Q24
MPSA93
NORMAL = HI
R48
CLIP
22K
R47
47K
210mW
-48V
R45
47K
50mW
D8
1N4148
R44
47K
50mW
Q23
MPSA43
-48V
DC OFFSET
HI = NORMAL
LEFT
33