Cambridge Audio 840A - Front Panel PCB; Front Panel PCB Schematics

Cambridge Audio Azur 840A Amplifier
AP16369/3 Front Panel PCB Schematic (Microcontroller & LCD)
MCLR/VPP
1
RA0/AN0
2
RA1/AN1
3
RA2/AN2
4
RA3/AN3/VREF
5
RA4/T0CKI
6
RA5/AN4/SS
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
SW1
SW-TACT
SW2
SW-TACT
SW3
SW-TACT
SW5
SW-TACT
SW6
SW-TACT
SW7
SW-TACT
SW8
SW-TACT
SW4
SW-TACT
SW9
SW-TACT
SW10
SW-TACT
SW11
SW-TACT
INPUT 1 INPUT 2 INPUT 3 INPUT 4
INPUT 5 INPUT 6 INPUT 7 TAPE MON
MODE
spare
+5V
LOGIC GND
LCD DISPLAY CONN
C10
100n CER
C11
100n CER
LOGIC GND
SERIAL DATA
SERIAL CLOCK
SERIAL STROBE
SERIAL CONTROL OUT
SERIAL IN FROM A-BUS HUB BOARD
OVERLOAD
HUB DATA
CLIP DETECT
MAINS FAIL
DC OFFSET
PHONES DETECT
PORT B HAS WEAK PULLUPS
RB4-RB7 HAS INTRPT ON CHANGE
R1
22R
R2
43R
Q2
BC337
LOGIC GND
R4
4K7
C1
100n
C2
100nF
ON/STBY
SPEAKER SELECT
LOGIC GND
ROW 3
ROW 2
ROW 1
COL 1 COL 2 COL 3 COL 4
X1
CRYSTAL
FREQ=20MHz
C5
22pF
C6
22pF
LOGIC GND
+5V
LOGIC GND
CONNECTOR TO PREAMP PCB
SERIAL IN FROM A-BUS HUB BOARD
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
LOGIC GND
TX
RX
RS232 & IR CABLE TO HUB PCB
IR IN (FROM RECEIVER ON PREAMP BOARD)
C GND
3
ASW
1
BSW
2
FIX2
5
FIX1
4
ROT1
NOBLE16ENCODER
POSITION FOR
EXTRA SWITCH
AK
D2
BLUE LED
ON/STBY LED
IR IN (FROM JACK & PHONO ON HUB PCB)
+15V
IR GND
IR IN
RS232 GND
R10
10R
C9
100N CERAMIC
SERIAL RX 232
C4
10U 16V
C3
10U 16V
R5
100R
C20
100nF
LOGIC GND
C21
100n
LOGIC GND
LOGIC GND
Q4
BC337
+15V
RS232 TX
R13
22K
R12
2K2
LOGIC GND
SERIAL TX 232
Q3
BC337
+5V
D3
1N4002
RS232 RX
R11
10K
R9
22K
LOGIC GND
SERIAL RX 232
RS232 RX
RS232 TX
SERIAL TX 232
PROGRAM_CLOCK
PROGRAM_DATA
PGM
MCLR HUB
R14
10K
+5V
+5V
Programming Signals
To ABUS Hub PIC
RS232 TX
RS232 RX
MCLR HUB
PGM
PROGRAM_DATA
PROGRAM_CLOCK
HUB CLOCK
HUB CLOCK
HUB DATA
R3
2K2
OVER TEMP
OVER TEMP
1
2
3
4
5
6
7
8
9
10
12
13
11
CN3
FFC 13WAY
BLOCK
PIC TX
SHIFT REG ENABLE
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
U2
74HC4094
VDD=+5V
VSS=LOGIC GND
SHIFT REG ENABLE
SERIAL DATA
SERIAL CLOCK
BLOCK
PIC TX
IR CONTROL
PHONES DETECT
OVERLOAD
DC OFFSET
MAINS FAIL
LCD DECOUPLE
C7
100nF
LOGIC GND
+5V
SHIFT REG DECOUPLE
1
2
3
4
5
6
7
8
9
10
11
12
CN1
FFC 12WAY
12
15 16
1
2
3
4
5
6
1a
2a
3a
4a
5a
6a
7
8
7a
8a
CN2
CONN-8 DUAL BOT
RS
E
LCD DATA SHIFT REGISTER
2
1
16
15
LCD CONN ORIENTATION FROM FRONT
C15
100pF
C16
100pF
C17
100n
C18
100n
C19
100n
CLIP DETECT
PIC INPUT EMC CAPS
LED BACKLIGHT POWER
R6
1K1
R7
2K2
R8
1K1
SPEAKER TEST
SPEAKER TEST
C22
100n
+5V
TRISTATE LED CONTROL
0=BRIGHT
TRISTATE= OFF
1= DIM
R15
10K
LOGIC GND
R16
47R
C23
100N CERAMIC
LOGIC GND
FRONT PANEL GROUNDING
Q5
BC337
R17
10K
R18
2K2
C24
10U 16V
Q6
BC337
R19
10K
LOGIC GND
FRONT PANEL GND
FRONT PANEL GND
P2
PAD
P3
PAD
Q1
BC327-25
2
CW
3
CCW
1
PR1
PRESET 20K 3296W
CW
Q8
BC327-25
R23
10R
R24
10R
D4
1N4148
D5
1N4148
D6
1N4148
D7
1N4148
D8
BZX79C2V7 500MW
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