Cambridge Audio Integrated Amplifier Azur 740A User manual

Gallery Court Hankey Place London SE1 4BB UK
Tel: [phone] Fax: [phone]
740A
Issue Date: 8th August 2007
SERVICE MANUAL
SPECIFICATIONS:
Power Output 100W RMS into 8 Ohms
150W RMS into 4 Ohms
THD (unweighted) < 0.001% 1 kHz
At 80% of rated power
< 0.01% 20 Hz – 20 kHz
At 80% of rated power
Frequency Response 10 Hz – 50 kHz +/- 1 dB
S/N Ratio (ref 1W/8 Ohms) > 96 dB
Input Impedances Inputs 1-6 47 kOhm
Power Amp Damping Factor > 110 at 1 kHz
Max Power Consumption 750W
Minimum Power Consumption Active (no signal) 45W
Standby6W
Bass & Treble Controls Shelving Type
Max bass boost/cut
+/-10 dB at 10 Hz
Max treble boost/cut
+/- 7.5 dB at 20 kHz
Dimensions 115 x 430 x 350mm
(4.5 x 16.9 x 13.8”)
Weight 10.7kg (23.5Lbs)
AP22267/1
1

740A SERVICE MANUAL
TABLE OF CONTENTS
Safety Precautions & Important Notes 4
Exploded Diagrams 5-8
Exploded Diagram Parts List 9
Front Panel PCB Schematic (Tone Control) 10
Front Panel PCB Schematic (Microcontroller & LCD) 11
Front Panel PCB Layout (Top Side) 12
Front Panel PCB Layout (Bottom Side) 13
Front Panel PCB BOM 14-15
Preamp PCB Schematic (Tone Control) 16
Preamp PCB Schematic (Protection Circuitry) 17
Preamp PCB Schematic (Power Supply) 18
Preamp PCB Schematic (Headphone Driver) 19
Preamp PCB Schematic (Buffers & Switches) 20
Preamp PCB Board Layout (Top Side) 21
Preamp PCB Board Layout (Bottom Side) 22
Preamp PCB BOM 23-26
Amplifier Schematic (Speaker PCB) 27
Amplifier Schematic (Right Channel) 28
Amplifier Schematic (Left Channel) 29
Amplifier Schematic (Protection) 30
Amplifier Schematic (Power Supply) 31
Amplifier PCB Board Layout (Top Side) 32
Amplifier PCB Board Layout (Bottom Side) 33
Amplifier PCB BOM 34-36
Abus Schematic 37
Abus PCB Board Layout (Top Side) 38
Abus PCB Board Layout (Bottom Side) 39
Abus PCB BOM 40-41
Mains Schematic (Mains) 42
Mains PCB Board Layout (Top Side) 43
Mains PCB Board Layout (Bottom Side) 44
Mains PCB BOM 45
2

ICPinLayoutDetails____________________________________________46‐51
ServiceModeInstructions________________________________________52
ProceduretoUpgradeSoftware___________________________________53
KandaPICHandHeldProgrammerModificationInstructions____________54‐58
RevisedFrontPanelSchematic–toimproveencoderreliability:
(seeServiceBulletinTNBC‐0035)__________________________________59‐60


SAFETY PRECAUTIONS & IMPORTANT NOTES
1. Check that the rear of the product indicates the correct supply voltage for
your area.
2. The lighting flash with the arrowhead within an equilateral
triangle is intended to alert the user or service agent to the
presence of dangerous voltages within the product enclosure that
may be of sufficient magnitude to constitute a risk of electric shock
to persons.
3. The exclamation point within an equilateral triangle is intended
to alert the user or service agent to the presence of important
operating and maintenance (Servicing) instructions in the literature
accompanying the appliance.
4. This product complies with EEC Low Voltage (73/23/EEC) and
Electromagnetic Compatibility (89/336/EEC) Directives when used and serviced
in accordance with this manual. For continued compliance all components
marked safety and EMC critical must only be replaced by Cambridge Audio
approved parts.
5. Any unauthorised design alterations or additions will void the manufacturer’s
warranty; furthermore the manufacturer cannot accept responsibility for personal
injury or property damage resulting therefrom.
6. When servicing, care should be taken to observe the original routing and
dressing of the leads and it should be confirmed that they have been returned to
normal after re-assembly.
Notes on chip component replacement
Never reuse a component that has been removed from a PCB
Notice that the minus side of a tantalum capacitor may be damaged by heat
COPYRIGHT NOTICE.
© 2007Audio Partnership PLC. All rights reserved.
Cambridge Audio and Azur are registered trademarks for Audio Partnership PLC. This document
may not be reproduced, distributed, transmitted, displayed, published, or broadcast without the
express written prior permission of Audio Partnership PLC.
Alteration or removal of any trademark, copyright, or other notice from this content is prohibited.
Information provided in this document is provided solely for the use of official service agents in
repairing and servicing Audio Partnership PLC products.
4

Cambridge Audio Azur 740A Amplifier
Exploded Diagram (Complete Unit)
3
3
2
15
To enhance viewing, please print to A3 5

Cambridge Audio Azur 740A Amplifier
Exploded Diagram (Chassis Assembley)
13
10
9
8
1
16
To enhance viewing, please print to A3 6

Cambridge Audio Azur 740A Amplifier
Exploded Diagram (Front Panel Assembley)
7
6
4
5
To enhance viewing, please print to A3 7

Cambridge Audio Azur 740A Amplifier
Exploded Diagram (Rear Panel Assembley)
11
12
14
To enhance viewing, please print to A3 8

Cambridge Audio Azur 740A Amplifier
Exploded Diagram Parts List
noitpircseDnoit
angis
e
Dyro
t
caF
r
e
b
m
u
Nt
raPfeRg
niw
a
rD
1 PY1237 3200-063073E000 Azur-740A 230V Transformer TI-063073D For EU Version
- PY1242 3200-063074E000 Azur-740A 110V Transformer For CU (USA) Version
2 PY1338 6574-150018E000-02 Azur 740A Top Panel-S (With Painted)
- PY1339 6574-150018E000-01 Azur 740A Top Panel-B (With Painted)
3 PY1340 6574-150020E000-02 Azur-740A Side Panel-S (With Painted)
- PY1341 6574-150020E000-01 Azur-740A Side Panel-B (With Painted)
4 PY1342 8574-015010E301 Azur-740A Front Panel-S Assy Rev A (Metal plus PCB)
- PY1343 8574-015020E301 Azur-740A Front Panel-B Assy Rev A
5 PY1344 6574-150029E000A01 Azur-740A Front Panel Artwork-S (AP200931) (metal)
- PY1345 6574-150029E000-01 Azur-740A Front Panel Artwork-B
6 PY1346 9474-015000E041 Azur-740A Control PCBA Rev A 7 PY1138 2409-010200E001 Rotary Encoder Switch REB161(9*7)PVB20FHINB1-2-24E 8 PY1347 9474-015000E091 Azur-740A Amp Power PCBA (AP19797/A) Rev A <T Type>
9 PY1348 9474-015000E001 Azur-740A Protection Circuitry PCB-A Assy Rev A
10 PY1349 9474-015000E101 Azur-740A Protection Circuitry PCB-B Assy Rev A 11 PY1350 9474-015000E331 Azur-740A A-Bus Hub PCBA REV A 12 PY1351 2404-040100E001 Piano DIP Switch 4P DPL-04K Series 13 PY1352 9474-015000E341 Azur-740A Input PCBA Rev A <T-Type Resistor>
14 PY1322 2333-008919E003 WP8-22 8 Way SPK Terminal 4Blk/4Red Gold Plating for 740A
15 PY1165 9805-084000E001 Azur-740/840/A/C Remote Control Assy Rev A
16 PY1122 6074-150004E000 Plastic foot black
- PY1125 6074-150004E000A01 Plastic foot silver
9

Cambridge Audio Azur 740A Amplifier
AP19784/3 Front Panel Circuit Diagram (Tone Control)
R103
4K7 1/4W Metal Film
+15V
-15V
R106
2K2 1/4W Metal Film
R107
2K2 1/4W Metal Film
R203
4K7
1/4W Metal Film
+15V
-15V
R206
2k2 1/4W Metal Film
R207
2K2 1/4W Metal Film
R R
L
L
2 3
1
8 4
U100:A
NE5532P
Audio Op Amp
6 5
7
U100:B
NE5532P Audio Op Amp
2 3
1
8 4
U200:A
NE5532P Audio Op Amp
6 5
7
U200:B NE5532P Audio Op Amp
R
R
L
L
C104 47nF 63V
Met. Polyester
C106 47nF 63V
Met. Polyester
C204 47nF 63V
Met. Polyester
C206 47nF 63V Met. Polyester
C103 10pF 50V NP0 Ceramic
C203 10pF 50V
NP0 Ceramic
C207
10pF 50V
NP0 Ceramic
C107 10pF 50V NP0 Ceramic
C101
1.5nF 63V
Met. Polyester
C201
1.5nF 63V
Met. Polyester
R
L
-15V
+15V
SHIELD_SUPPLY
1 2 3 4
CN4
4Way
Right Angle Header
SHIELD_L2
SHIELD_R2
RIGHT
LEFT
1
2
3
4
5
6
CN6 6Way
Right Angle Header
1
2
3
4
5
6
CN7
6Way
Right Angle Header
RA
RTB
RC
RA
RBB
RC
RA
RTB
RBB
RC
LA
LTB
LC
LA
LBB
LC
LA
LTB
LBB
LC
VR1:A 5k Push Action Linear Pot
VR1:B 5k
Push Action Linear Pot
VR2:A
5k
Push Action Linear Pot
C10 680nF 63V Met. Polyester
VR2:B
5k Push Action Linear Pot
C18 680nF 63V Met. Polyester
GUARD
R
L
1
2
3
4
5
CN8 5Way
Straight Header
1
2
3
4
CN10 4Way
Straight Header
LK37
24 AWG
LK38
24 AWG
LK39
24 AWG
RR
L L
LK40
24 AWG
LK1 24 AWG
1 2
3
4 5 6 7 8
CN5 8Way
Right Angle Header
R22
1K1
1/8W Metal Film
R21
1K1
1/8W Metal Film
R25 2K2 1/8W Metal Film
R26 2K2 1/8W Metal Film
R24
2K2 1/8W Metal Film
R23
2K2 1/8W Metal Film
R20
1K1 1/8W Metal Film
R18 1K1 1/8W Metal Film
1
2 3
4 5 6
1 2 3 4 5
CA1
See AP20044/1 6Wayto5Way Screened Audio cable
1 2 3 4 5 6
1 2 3 4
CA2 See AP20043/1 6 Way to 4 Way Screened Audio cable
To enhance viewing, please print to A3 10

Cambridge Audio Azur 740A Amplifier
AP19784/3 Front Panel Circuit Diagram (Microcontroller & LCD)
PGD
2.
PGC
1.
MCLR/VPP
1
RA0/AN0
2
RA1/AN1
3
RA2/AN2/Vref-/CVref
4
RA3/AN3/VREF+
5
RA4/T0CKI/C1OUT
6
RA5/AN4/SS/C2OUT
7
RE0/RD/AN5
8
RE1/WR/AN6
9
RB4
37
RB3/PGM
36
RB2
35
RB0/INT
33
VDD
32
VSS
31
RD7/PSP7
30
RD6/PSP6
29
RB1
34
RD5/PSP5
28
RD4/PSP4
27
RC7/RX/DT
26
RC5/SDO
24
RC4/SDI/SDA
23
RD3/PSP3
22
RD2/PSP2
21
RC6/TX/CK
25
VDD
11
VSS
12
OSC1/CLKIN
13
OSC2/CLKOUT
14
RCO/T1OSO/T1CKI
15
RC1/T1OSI/CCP2
16
RC2/CCP1
17
RC3/SCK/SCL
18
RD0/PSP0
19
RE2/CS/AN7
10
RD1/PSP1
20
RB5
38
RB6/PGC
39
RB7/PGD
40
U1 PIC16F877A-I/P PROGRAMMED_WITH=AP20357/x
SW1
KPT-1105A
SW2
KPT-1105A
SW3
KPT-1105A
SW4
KPT-1105A SW7 KPT-1105A
SW8 KPT-1105A
SW9 KPT-1105A
INPUT 1 INPUT 2 INPUT 3
INPUT 4 INPUT 5 TAPE MON
MODE
+5V
LCD DISPLAY CONN
C1
100nF 50V Mono Ceramic
C2 100nF 50V Mono Ceramic
SERIAL DATA
SERIAL CLOCK
INPUT STROBE
VI/SHORT
CLIP DETECT MAINS FAIL DC OFFSET
PHONES DETECT
C4 100nF 50V Mono Ceramic
ON/STBY
ROW 3
ROW 2
COL 1 COL 2 COL 3
X1
Strip Cut Crystal 4MHz
C5
22pF 50V NP0 Ceramic
C6
22pF 50V
NP0 Ceramic
Vss 1
Vdd 2
Vo 3
RS 4
R/W 5
E 6
D0 7
D1 8
D2 9
D3 10
D4 11
D5 12
D6 13
D7 14
LED A 15
LED K 16
CGND
3
ASW
1
BSW
2
FIX2
5
FIX1
4
ROT1
Noble Rotary Encoder
C7 10uF 16V Electrolytic
C8
10uF 16V Electrolytic
C9
100nF 50V Mono Ceramic
PREAMP RELAY
VOLUME STROBE
+5V
+5V
OVER TEMP
D
2
CLK
3
STB
1
OE
15
Q0
4
Q1
5
Q2
6
Q3
7
Q4
14
Q5
13
Q6
12
Q7
11
QS
9
QS
10
VCC
16
GND
8
U2
M74HC4094B1R
OVER TEMP
VI/SHORT
DC OFFSET
LCD DECOUPLE
21
15 16
1 2
3
4
5
6
1a 2a
3a 4a
5a
6a
7
8
7a
8a
CN1
2x8 Way
DIL Bottom Entry Header
RS
E
2
1
16
15
LCD CONN ORIENTATION FROM FRONT
CLIP DETECT
ON/OFF
BRIGHT
CONTROL BUS IR
+5V
SERIAL CLOCK
SERIAL DATA
INPUT STROBE
ABUS IR
POWER AMP RELAY
LCD STR.
SW6 KPT-1105A
SW5
KPT-1105A
1
P5
C11
10nF 50V
Ceramic
1
P2
C12 10nF 50V Ceramic
1
P3
C13
10nF 50V Ceramic
1
P4
C14 10nF 50V Ceramic
1
P1
C15 10nF 50V Ceramic
VOLUME STROBE
SPEAKER
ABUS IR+5V
SPEAKER A RELAY
RC5 BLOCK RC5 TX
C16
100nF 50V Mono Ceramic
+5V
C17
10uF 16V Electrolytic
PHONES DETECT
CONTROL BUS IR
PREAMP RELAY
SPEAKER A RELAY
SPEAKER B RELAY
SPEAKERBRELAY
TO POWER AMP PCB
TO PRE AMP PCB
MAINS FAIL
RC5 BLOCK
RC5 TX
POWER AMP RELAY
+5V
D1
Blue Azur LED
POWER AMP RELAY
DIRECT RELAY
DIRECT RELAY
SW10
KPT-1105A
DIRECT
ROW 4
+5V
R19
100R 1/4W Metal Film
R3
1K2
1/4W Metal Film
R6 300R 1/4W Metal Film
R1
56R 1/4W Metal Film
R2
56R 1/4W Metal Film
R5 10K
1/4W Metal Film R10
10K 1/4W Metal Film
R11
10K 1/4W Metal Film
R15
220R 1/4W Metal Film
R12
220R 1/4W Metal Film
R14 47R 1/4W Metal Film
R8 10R
1/4W Metal Film
R9 10R 1/4W Metal Film
R16
1K 1/8W Metal Film
R17
1K 1/8W Metal Film
R4
10K 1/4W Metal Film
R7
10K
1/4W Metal Film
1 2
3 4 5 6
7 8 9
10
CN9 10 Way Right Angle Header
+5V
3
OPT
1
GND
2
U3 TSOP34836 36KHz
1 2 3 4 5 6
CN2
6Way Right Angle Header
PIC IR ON/OFF
+5V
MCLR
+5V
+5V
PIC IR ON/OFF
+5V
1 2
3
4
5 6
CN11 6Way
+5V
C3
47nF 50V Ceramic
C22 47nF 50V Ceramic
+5V
D4 1N4148 Signal Diode
MCLR
LK2 24 AWG
LK3
24 AWG
+5V +5V
LK4
24 AWG
LK6
24 AWG
LK7
24 AWG
+5V +5V
LK9
24 AWG CONTROL BUS IR CONTROL BUS IR
LK10
24 AWG
+5V +5V
LK12
24 AWG
LK13
24 AWG
LK14
24 AWG
LK15
24 AWG
LK16
24 AWG
LK17
24 AWG
LK20
24 AWG
LK21
24 AWG
LK22 24 AWG
LK23
24 AWG
LK24
24 AWG
LK25
24 AWG
LK26
24 AWG
LK27
24 AWG
LK28 24 AWG
LK29
24 AWG
LK30
24 AWG
LK31
24 AWG
LK33
24 AWG
LK34 24 AWG
LK32
24 AWG
LK35 24 AWG
LK36
24 AWG
LK8 24 AWG
2 3
1
U4:A
VCC=+5V
M74HC02
GND=GND
5 6
4
U4:B VCC=+5V M74HC02 GND=GND
8 9
10
U4:C VCC=+5V
M74HC02
GND=GND
11 12
13
U4:D VCC=+5V M74HC02
GND=GND
LK5 24 AWG
LK11
24 AWG
R36
10K 1/4W Metal Film
R39
1K 1/8W Metal Film
R28
47K 1/4W Metal Film
R34 10K 1/4W Metal Film
R35
47K 1/8W Metal Film
R27
47K 1/4W Metal Film
R29
47K 1/4W Metal Film
R30 47K 1/4W Metal Film
R31
47K 1/4W Metal Film
R32
100K
1/4W Metal Film
R33
10K
1/4W Metal Film
PGD PGC
Q3
BC337-25 NPN Signal
Q1
BC337-25 NPN Signal
Q2
BC337-25 NPN Signal
1
2 3 4 5 6 7 8 9
CN3 9Way Right Angle Header
R13 47K 1/8W Metal Film
LCD STR
LCD STR.
LCD STR
BRIGHT
ON/OFF
+5V
LK18 24 AWG
2
CCW
1
CW
3
PR1
Multiturn 500R
To enhance viewing, please print to A3 11

Cambridge Audio Azur 740A Amplifier
AP19784/3 Front Panel Board Layout (Top Side)
To enhance viewing, please print to A3 12

Cambridge Audio Azur 740A Amplifier
AP19784/3 Front Panel Board Layout (Bottom Side)
To enhance viewing, please print to A3 13

AP19787/4
AP Part
No Value Description/Type Qty Component Ident Type Tolerance Factory P/N Notes
10
R
1/4W Metal Film 2 R8, R9 1%
47
R
1/4W Metal Film 1 R14 1%
56
R
1/4W Metal Film 2 R1, R2 1%
100
R
1/4W Metal Film 1 R19 1%
220
R
1/4W Metal Film 2 R12, R15 1%
300
R
1/4W Metal Film 1 R6 1%
1
K
1/8W Metal Film 3 R16, R17, R39 1%
1K1 1/8W Metal Film 4 R18, R20-R22 1%
1K2 1/4W Metal Film 1 R3 1%
2K2 1/8W Metal Film 4 R23-R26 1%
2K2 1/4W Metal Film 4 R106, R107, R206,
R20
7
1%
4K
7
1/4W Metal Film 2 R103, R203 1%
10K 1/4W Metal Film 8 R4, R5, R7, R10, R11,
R33, R34, R36 1%
47
K
1/8W Metal Film 2 R13, R35 1%
47
K
1/4W Metal Film 5 R27-R31 1%
100
K
1/4W Metal Film 1 R32 1%
500
R
Multiturn 1 PR1 10%
5
k
Push Action Linear Pot 2
V
R1, VR2 1065-002500E12
0
10pF 50V NP0 Ceramic 4 C103, C107, C203,
C20
7
5% 1181-100042-000
22pF 50
V
NP0 Ceramic 2 C5, C6 5% 1181-220042-00
0
1.5nF 63
V
Met. Polyeste
r
2 C101, C201 10% 1117-152052-90
0
10nF 50
V
Ceramic 5 C11-C15 10% 1100-103043-00
0
47nF 50
V
Ceramic 2 C3, C22 10% 1100-473044-00
0
47nF 63V Met. Polyester 4 C104, C106, C204,
C206 10% 1117-473053-000
100nF 50V Mono Ceramic 5 C1, C2, C4, C9, C16 10% 1100-104043-000
680nF 63
V
Met. Polyeste
r
2 C10, C18 10% 1117-684053E00
0
10uF 16
V
Electrolytic 3 C7, C8, C17 20% 1102-100014-00
0
2x8 Way DIL Bottom Entry
Header 1 CN1 2350-016300-001 Please mount on track side of PCB
6 Way Right Angle Heade
r
3 CN2, CN6, CN7 2300-006010-00
0
9 Way Right Angle Heade
r
1 CN3
4 Way Right Angle Heade
r
1 CN4 2300-004010-00
0
8 Way Right Angle Heade
r
1 CN5
5 Way Straight Heade
r
1 CN8 2300-005000-00
0
10 Wa
y
Right Angle Heade
r
1 CN9
4 Way Straight Heade
r
1 CN10 2300-002000-001
6 Way IDC Programming
Header 1 CN11
4MHz Strip Cut Crystal 1 X1
Blue Azur LED 3mm 1 D1 3100-000030-003
75V 150m
A
Signal Diode 1 D4 1401-141480-00
0
DIODES
Cambridge Azur 740A Front Panel PCB Assembly BOM
RESISTORS
RESISTORS VARIABLE
CAPACITORS
CONNECTORS
CRYSTALS
Note: resistors, capaciotrs and other 'generic' electronic components are
not usually stocked by the manufacturer. Please obtain these locally. 14

AP19787/4
AP Part
No Value Description/Type Qty Component Ident Type Tolerance Factory P/N Notes
Cambridge Azur 740A Front Panel PCB Assembly BOM
40 Pin Flash Microcontroller 1 U1 PIC16F877A
-
I/P
Program with
software:
AP20357/x
Please add
version label!
PY524 M74HC4094B 8 Bit Shift Register 1 U2 M74HC4094
B1
R
4174-409052-600
PY755 36KHz IR Receiver IC 1 U3 TSOP34836 3001-348360-000
PY471 Quad 2 Input NOR Gate 1 U4 M74HC02
PY108 Dual
A
udio Op Amp 2 U100, U200 NE5532P 4155-320052-90
0
PY214 45V 300m
A
NPN Signal 3 Q1-Q3 BC337-25 1300-337000-10
0
INTEGRATED CIRCUITS
TRANSISTORS
Note: resistors, capaciotrs and other 'generic' electronic components are
not usually stocked by the manufacturer. Please obtain these locally. 15

Cambridge Audio Azur 740A Amplifier
AP19799/6 Preamp PCB Circuit Diagram (Tone Control)
+15V
-15V
LCh In
RCh In
1
2 3 4
5 6
CN5
6Way
Straight Header TO POWER AMP
C49
NP Electrolytic
100uF 25V
C47
NP Electrolytic 100uF 25V
RCh Out
LCh Out
C50
Polypropylene 100nF 100V
C48 Polypropylene
100nF 100V C78
100uF 25V Electrolytic C77 100uF 25V Electrolytic
ZCEN 1
ZCEN2 2
CSN 3
SDATAI 4
DGND 5
REF 6
DVSS 7
SCLK 8
SDATAO 9
TE1 10
TE2 11 TE3 12
IN2
13
REF2A
14
REF2B
15
OUT2
16
AVDD2
17
AVSS2
18
AVSS1
19
AVDD1
20
OUT1
21
REF1B
22
REF1A
23
IN1
24
U2
YAC526
Volume IC
R46
1/4W Metal Film
330R R47
1/4W Metal Film 330R
L
R45
1/4W Metal Film 330R R44
1/4W Metal Film 330R
R
1 2
3 4
CN13 4 Way Straight Header
RL
1
2 3 4 5 6
7
8
9
CN12 9 Way Straight Header
R
L+15V
-15V
R
L
RCh Out
LCh Out
C38
Electrolytic 470uF 10V
C39
Electrolytic 470uF 10V
C37
47nF 63V Met. Polyester
C40
47nF 63V Met. Polyester
C56
Electrolytic 470uF 10V
C42
Electrolytic
470uF 10V
C55
47nF 63V Met. Polyester
C41
47nF 63V Met. Polyester
VI
2VO 3
ADJ 1
U7 LM337T
Adj Regulator
C11 47nF 63V Met. Polyester
C15
100uF 25V
Electrolytic
C14 47nF 63V Met. Polyester
R15 120R 1/8W Metal Film
R13
620R 1/8W Metal Film
R14
10k 1/8W Metal Film
-15V VI
2VO 3
ADJ 1
U6 LM337T
Adj Regulator
R142 120R 1/8W Metal Film
R141
620R 1/8W Metal Film
R140
10k 1/8W Metal Film
-15V
C3
47nF 63V
Met. Polyester
C16
100uF 25V Electrolytic
C17
47nF 63V Met. Polyester
R16
220R
1/8W Metal Film
R11
3k
1/8W Metal Film
R12
1k8 1/8W Metal Film
+15V VI
3VO 2
ADJ
1
U8 LM317T Adj Regulator
STAR
STAR DGND
R36 220R 1/8W Metal Film
R35
220R
1/8W Metal Film
C10 Mono Ceramic 100nF 100V
-6.6VD
-6.6VD
-6.6VA
+6.6VA
-6.6VA
R34
220R
1/8W Metal Film
R33
220R 1/8W Metal Film
+6.6VA
R129
10k
1/8W Metal Film
Volume Strobe Data Clock
C35 47uF 35V Electrolytic
C8
47uF 35V
Electrolytic
C12
47uF 35V
Electrolytic
C13
47uF 35V
Electrolytic
L RSTAR
+5V
D1
1N4004 Rectier Diode
Q13
MPSA14 NPN Darlington R131
10k 1/8W Metal Film
R19
1k 1/4W Metal Film
MAIN
Tone Defeat Relay
C36 Mono Ceramic 100nF 100V
C9 Mono Ceramic 100nF 100V
C34
47uF 35V
Electrolytic
STAR
R
L
R130 220R 1/8W Metal Film
C119 Electrolytic 470uF 10V
C120 Mono Ceramic 100nF 100V
FB3 On 24AWG Wire 1uH Ferrite
3
4
5
RL1:B
ME2-5S 2P2T Relay
6
7 8RL1:C
ME2-5S 2P2T Relay
1
2
RL1:A
ME2-5S 2P2T Relay
+5V
D13
1N4004
Rectier Diode
1
2
RL2:A
ME2-5S 2P2T Relay
HP
Q14
BC327-25 PNP Signal
R49 1206 Thick Film 10k
R105
1206 Thick Film 1k
RC5 Block
3
4 5RL2:B
ME2-5S 2P2T Relay
6
7 8RL2:C
ME2-5S 2P2T Relay
HP
LK1 24 AWG 12.5mm Pitch
To enhance viewing, please print to A3 16

Cambridge Audio Azur 740A Amplifier
AP19799/6 Preamp PCB Circuit Diagram (Protection Circuitry )
Relay Gnd Clean Gnd
R82
1k 1/8W Metal Film For 1mA R71 100R 1/8W Metal Film
DGND
5 6
7
U13:B
LM393AP Dual Comparator
D8 1N4148 Signal Diode
+5V
Senses a DC resistance of 2 ohms or less
D9
Rectier Diode 1N4004
PIC VI/Short
R Speaker Test
DGND
+5V
R Speaker Test
Speaker A Relay
UNREG
POWER AMP STANDBY
UNREG
DGND
1 2
3
CN8
3Way
Straight Header
R70 2W Carbon 220R
PIC DC
PIC Clip
PIC VI/Short
PIC Temp
Preamp Standby
Mains Fail
1 2 3
4
5
6 7 8 9
10
CN3 10 Way Straight Header To PIC
6SHDNHU&DEOH6KRUW&LUFXLW'HWHFWRU
3 2
1
84
U14:A
LM393AP Dual Comparator
1 2 3 4 5
CN7
5Way
Straight Header
DGND
PIC VI/Short
PIC DC
PIC CLIP
Temp Sense
R144 1/4W Metal Film 10k
+5V
PIC Temp
R65
910R
1/8W Metal Film 910 / (910 + 10k) with ZP221A501E voltage gives 100deg C cutout
+5V
Temp Sense
R72 4k7
1/8W Metal Film
R74
10k
1/8W Metal Film
R68 4k7 1/8W Metal Film Open Collector Output
R69
100k 1/8W Metal Film
DGND
+5V
L Speaker Test
R80 1k 1/8W Metal Film For 1mA
R81
10k
1/8W Metal Film
R75 100R 1/8W Metal Film
R73
4.7R
1/8W Metal Film
3
2
1
84
U13:A
LM393AP Dual Comparator
+5V
R64
4k7 1/8W Metal Film (Open Collector Output)
D10
Rectier Diode 1N4004
L Speaker Test
Speaker B Relay
RC5 Block
RC5 TX
Tone Defeat Relay
Head Phones Detect
5 6
7
U14:B
LM393AP Dual Comparator
Speaker A Relay
Speaker B Relay
C112
100nF 50V Mono Ceramic
C58
Mono Ceramic
100nF 100V
DGND
DGND
1 2
3
4 5 6
CN1 6Way Straight Header
Head Phones Detect Gnd
PIC GND
PIC IR on/o
1 2 3 4 5 6 7
CN9
7Way Straight Header
C21 100uF 16V Electrolytic
DGND
+5V
D14
1N4148
Signal Diode
PIC VI/Short
R29
4k7 1/8W Metal Film
(Open Collector Output)
C7
100uF 16V Electrolytic
C6
Mono Ceramic 100nF 100V
C63
10nF 50V
Ceramic
3URWHFWLRQ 6LJQDOV 7R$PS 3,&
6LJQDOV
6SHDNHU 3&%
6LJQDOV
3,&
6LJQDOV
0DLQV
3&% 6LJQDOV
C51
100uF 16V Electrolytic
DGND
C54
100uF 16V Electrolytic
DGND
To enhance viewing, please print to A3 17

Cambridge Audio Azur 740A Amplifier
AP19799/6 Preamp PCB Circuit Diagram (Power Supply)
VI
1VO 3
GND
2
U3 L7815
Regulator
VI
2VO 3
GND 1
U4 L7915
Regulator
DGND
C19
100uF 25V Electrolytic 105
C18
100uF 25V Electrolytic 105
1
2 3
CN6 3Way Straight Header
UNREG
Main
+15V
-15V
C26 2200uF 35V
Electrolytic
C32
2200uF 35V
Electrolytic
AC Sense 1
R132 10k 1/8W Metal Film
D3 Rectier Diode 1N4004
R67
4k7 1/8W Metal Film R66
4k7 1/8W Metal Film
+5V
Mains Fail
Main
W5
A
D11 Rectier Diode 1N4004 D12 Rectier Diode 1N4004
C29
Met. Polyester 39nF 250V
C30
No Fit Mono Ceramic
C28
No Fit
Mono Ceramic
C27
No t Mono Ceramic
C57 No Fit Mono Ceramic
C23
Met. Polyester 47nF 63V
C24
Met. Polyester 47nF 63V
C25
47nF 63V Met. Polyester
C33 47nF 63V Met. Polyester
Q10
BC337-25 NPN Signal
Q12
BC327-25 PNP Signal
Q11
BC327-25 PNP Signal
R127
1/4W Metal Film 4k7 22.5V 240V
R128
7k5 1/4W Metal Film 28V 240V
Q8
BC337-25 NPN Signal
R137 10k 1/8W Metal Film
Main
R139 10k
1/8W Metal Film
Preamp Standby
+5V
Q9
BC327-25 PNP Signal
R136
10k 1/8W Metal Film Q7
BC337-25 NPN Signal
R138
10k 1/8W Metal Film
-Unreg
R126 100k 1/8W Metal Film
FB5 On 24AWG Wire
1uH Ferrite
Main
R48
6k2 1/8W Metal Film
D2 Rectier Diode
1N4004
C31
Mono Ceramic 330nF 100V
AC Sense 1 AC Sense 2
AC Sense 2
D15
1N4148 Signal Diode
VI
1VO 3
GND
2
U5 L7805
Regulator
DGND
+5V
C22 47uF 35V Electrolytic
W6
A
STAR
WIRE1
C52
100nF 50V Mono Ceramic
C53 100nF 50V Mono Ceramic
D4
MBR1100
Schottky Rectier
D5
MBR1100 Schottky Rectier
D6
MBR1100 Schottky Rectier
D7
MBR1100 Schottky Rectier
R30
47R 2W Carbon
To enhance viewing, please print to A3 18

Cambridge Audio Azur 740A Amplifier
AP19799/6 Preamp PCB Circuit Diagram (Headphone Driver)
HP
+15V
-15V
R38
10R
1/4W Metal Film
R37 10R 1/4W Metal Film
6 5
7
U1:B
NE5532P Audio Op Amp
R8
1/4W Metal Film
1R
R6 1/4W Metal Film 1R
R41 1/4W Metal Film 2k7
R40
1/4W Metal Film 3k3
R43
1/4W Metal Film 560R
R42
1/4W Metal Film 560R
R39
1/4W Metal Film 5k6
R7 1/4W Metal Film
5k6
Q6
BD139 NPN Power
Q4
BD139 NPN Power
Q5 BD140 PNP Power
R9
1/4W Metal Film 180R
C44
Met. Polyester
47nF 63V
C45 47nF 63V Met. Polyester
2 3
1
84
U1:A NE5532P
Audio Op Amp
R3 1/4W Metal Film 1R R1
1/4W Metal Film 1R
R23
1/4W Metal Film 2k7
R22
1/4W Metal Film 3k3
R25
1/4W Metal Film 560R
R24 1/4W Metal Film 560R
R21
1/4W Metal Film
5k6
R2
1/4W Metal Film 5k6
Q3
BD139 NPN Power
Q2
BD139 NPN Power
Q1
BD140
PNP Power
R4
1/4W Metal Film 180R
R17 10R 2W Carbon R18 10R 2W Carbon
RCh HP Out
R32
1/4W Metal Film 100R
LCh HP Out
R27
1/4W Metal Film
100R
C43 Electrolytic
470uF 25V
C46
Electrolytic 470uF 25V
R5 360R 1/4W Metal Film
R10 360R
1/4W Metal Film
C2 10nF 63V Polyester
C1
10nF 63V Polyester
HP
R20
1/4W Metal Film 1k5 R31 1/4W Metal Film 1k5 R26 1/4W Metal Film 1k5 R28
1/4W Metal Film 1k5
HP HP
5FK2XW
/FK2XW
C5
680pF 50V NP0 Ceramic
C4
680pF 50V NP0 Ceramic
Head Phones Detect
Head Phones Detect Gnd
C117
100pF 50V
NP0 Ceramic
C118 100pF 50V NP0 Ceramic
Main HP
W1 B
WIRE2 W2
B
HP
W3
C
WIRE3 W4
C
RSW1 RSW2
R
L
GND
2 3 1 7 8
CN2
CK-6.35-08A Headphone Jack
To enhance viewing, please print to A3 19

Cambridge Audio Azur 740A Amplifier
AP19799/6 Preamp PCB Circuit Diagram (Buffers & Switches)
2 3
1
8 4
U12:A
NE5532P
Audio Op Amp
R123 220R 1/8W Metal Film
R122
220R 1/8W Metal Film
6 5
7
U12:B
NE5532P Audio Op Amp
2
3
1
8 4
U9:A
NE5532P Audio Op Amp
6 5
7
U9:B
NE5532P Audio Op Amp
-15V
+15V
STAR
STAR
+15V-15V
+15V
-15V
STAR
STAR
STAR STAR
RCh In LCh In
LCh Out
RCh Out
L
R
6
CN14:D AV4-8.4-9
3
CN15:B
AV4-8.4-9
6
CN15:D AV4-8.4-9
$X[
&'
'$%
'9'
0'
72
72
70
32
3
CN16:B AV4-8.4-9
6
CN16:D AV4-8.4-9
3
CN17:B AV4-8.4-9
PreOut Left
PreOut Right
PreOut Left
PreOut Right
6
CN17:D
AV4-8.4-9
1
2
CN18:A AV2-8.4-9
PIC GND
3
CN18:B
AV2-8.4-9 STAR
2
3
1
8
4
U19:A
NE5532P Audio Op Amp
-15V
+15V
STAR
C75
47nF 63V Met. Polyester
C76
47nF 63V Met. Polyester
STAR STAR
R109
47k 1/8W Metal Film
2
3
1
84
U18:A
NE5532P Audio Op Amp
STAR
R106
47k 1/8W Metal Film
2
3
1
84
U17:A
NE5532P Audio Op Amp
-15V
+15V
STAR
C84
Met. Polyester 47nF 63V
C83
Met. Polyester 47nF 63V
STAR STAR
R102
47k 1/8W Metal Film
2
3
1
84
U16:A
NE5532P Audio Op Amp
STAR
R98 47k 1/8W Metal Film
2
3
1
84
U15:A
NE5532P Audio Op Amp
-15V +15V
STAR
C108
Met. Polyester 47nF 63V
C109
Met. Polyester 47nF 63V
STAR STAR
R94
47k 1/8W Metal Film
2
3
1
84
U20:A
NE5532P Audio Op Amp
STAR
R86
47k 1/8W Metal Film
6
5
7
U18:B
NE5532P Audio Op Amp
-15V +15V
STAR
C68
47nF 63V
Met. Polyester
C67
47nF 63V Met. Polyester
STAR STAR
R104
47k 1/8W Metal Film
6
5
7
U19:B NE5532P Audio Op Amp
STAR
R108
47k
1/8W Metal Film
6
5
7
U16:B
NE5532P Audio Op Amp
-15V
STAR
C110
Met. Polyester 47nF 63V
C111
47nF 63V Met. Polyester
STAR STAR
R96
47k 1/8W Metal Film
6
5
7
U17:B
NE5532P Audio Op Amp
STAR
R100
47k 1/8W Metal Film
6
5
7
U20:B NE5532P Audio Op Amp
-15V +15V
C107
Met. Polyester 47nF 63V
C106
Met. Polyester 47nF 63V
STAR STAR
R121
47k 1/8W Metal Film
6
5
7
U15:B NE5532P Audio Op Amp
STAR
R92
47k
1/8W Metal Film
C59
47nF 63V
Met. Polyester
C60 47nF 63V Met. Polyester
R54 1k8 1/4W Metal Film
R55 1k8 1/4W Metal Film
STAR
R59 1k8 1/4W Metal Film
STAR
R58 1k8 1/4W Metal Film
C82
10pF 50V
NP0 Ceramic
C79 10pF 50V
NP0 Ceramic
R133
100R 1/4W Metal Film
R134 100R 1/4W Metal Film
C105
100pF 50V
NP0 Ceramic
C95
100pF 50V NP0 Ceramic
C91
100pF 50V
NP0 Ceramic
C85
100pF 50V NP0 Ceramic
C69
100pF 50V
NP0 Ceramic
C73
100pF 50V NP0 Ceramic
C74
100pF 50V NP0 Ceramic
C70
100pF 50V NP0 Ceramic
C86
100pF 50V NP0 Ceramic
C90
100pF 50V NP0 Ceramic
C94
100pF 50V NP0 Ceramic C98
100pF 50V NP0 Ceramic
R88
220R 1/8W Metal Film
R89
220R 1/8W Metal Film
R87 220R 1/8W Metal Film
R90
220R 1/8W Metal Film
3
CN14:B AV4-8.4-9
1
2
CN14:A
AV4-8.4-9
4
5
CN14:C AV4-8.4-9
1
2
CN15:A AV4-8.4-9
4
5
CN15:C AV4-8.4-9
1
2
CN16:A AV4-8.4-9
4
5
CN16:C AV4-8.4-9
1
2
CN17:A AV4-8.4-9
4
5
CN17:C
AV4-8.4-9
+15V
C72
NP Electrolytic 47uF 16V
C71 NP Electrolytic
47uF 16V
C113
NP Electrolytic
47uF 16V
C87
NP Electrolytic 47uF 16V
C88
NP Electrolytic 47uF 16V
C89
NP Electrolytic 47uF 16V
C92
NP Electrolytic 47uF 16V
C93 NP Electrolytic
47uF 16V
C96 NP Electrolytic 47uF 16V
C97 47uF 16V
NP Electrolytic
C103 NP Electrolytic 47uF 16V
C104 47uF 16V
NP Electrolytic
STAR
STAR
R56 470k 1/4W Metal Film
R57
470k 1/4W Metal Film
LCh HP Out
RCh HP Out
STAR R53
560R
1/4W Metal Film
R52 560R 1/4W Metal Film
1 2
3 4
5 6 7 8 9
CN4 9Way
Straight Header
To PIC
&ORFN
'DWD
,QSXW6WUREH
'*QGIURP3,& $%86,5
&RQWURO%XV,5
$%86,5
$%866WDWXV
/&K
*1'
5&K
1 2 3 4 5 6 7 8 9 10
CN10
FFC Connector ABUS Control Signals ABUS Control Signals
$%863&%'*QG
S1 Screw Terminal
R124 No Fit
1/4W Metal Film
J2
Screw Terminal
C102
220pF 50V
NP0 Ceramic
C100
NP0 Ceramic
220pF 50V
STAR
STAR
C99
220pF 50V NP0 Ceramic
C101
NP0 Ceramic 220pF 50V STAR
STAR
C115
220pF 50V NP0 Ceramic
C114
220pF 50V
NP0 Ceramic
2
3
1
84
U11:A
NE5532P Audio Op Amp
-15V
+15V
C61
47nF 63V Met. Polyester
C62
47nF 63V
Met. Polyester
STAR STAR
6
5
7
U11:B
NE5532P Audio Op Amp
STAR STAR
STAR
$%863&%9 +5V
R76 Wire Link
R77
Wire Link
R79 No Fit
STAR
R78 No Fit
STAR
STAR
POWER AMP STANDBY
Preamp Standby
R63
47R 1/4W Metal Film
R61
47R 1/4W Metal Film
R60
1/4W Metal Film 47R
R62
1/4W Metal Film
47R
C81
47nF 63V Met. Polyester
C80
47nF 63V Met. Polyester
Clock
Data
Switch Strobe
ABUS IR
ABUS IR CBUS IR CBUS IR
PIC GND
PIC GND
Data Clock
Switch Strobe
Volume Strobe 9ROXPH6WUREH
RC5 Block RC5 Tx PIC IR On/O
FB4
On 24AWG Wire 1uH Ferrite
ABUS
ABUS
C20
Mono Ceramic
100nF 100V
R50 1206 Thick Film
1k R51
1206 Thick Film
1k R83
1206 Thick Film 1k R84
1206 Thick Film
1k
R85
1206 Thick Film
1k
R91
1206 Thick Film 1k
R93
1206 Thick Film
1k
R95 1206 Thick Film
1k
R97
1206 Thick Film 1k
R99 1206 Thick Film 1k
R101 1206 Thick Film 1k
R103
1206 Thick Film
1k
STAR
1 2 3
CN11 3 Way Straight Header
ABUS Audio Out
C64 Ceramic 1nF 50V
C116
Ceramic No Fit
Vss
1
L-S1
2
L-S2
3
L-S3
4
L-COM1
5
L-S4
6
L-S5
7
L-S6
8
L-COM2
9
L-S7
10
L-S8
11
L-COM3
12
ST
13
GND
14
Vdd 28
R-S1 27
R-S2 26
R-S3 25
R-COM1 24
R-S4 23 R-S5 22 R-S6 21
R-COM2 20
R-S7 19 R-S8 18
R-COM3 17
DATA 16
CLK 15
U10 TC9163AF
&RQWURO%XV,5
3RZHUDPS6WDQGE\
To enhance viewing, please print to A3 20