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
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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