Front Panel Pcb Schematic (Microcontroller & Lcd) - Cambridge Audio 840A Service Manual

+15V
RS232 RX
+5V
R11 R12
10K 2K2
SERIAL RX 232
Q3
R9
BC337
22K
D3
1N4002
RS232 RX
LOGIC GND LOGIC GND
R5
C20
100R
100nF
+5V
LOGIC GND
C4
C2
10U 16V
100nF
LCD DECOUPLE
LOGIC GND
1 CN2 2
1a 1
LCD DATA SHIFT REGISTER
2a 2
3a 3 4
Q0
4a 4 5
Q1
5a 5
6
Q2
6a 6 7
Q3
7a 7 14
Q4
8a 8
13
Q5
12
15 16 Q6
11
CONN-8 DUAL BOT Q7
9
QS
10
QS
74HC4094
LCD DISPLAY CONN
VDD=+5V
VSS=LOGIC GND
R2
43R
LED BACKLIGHT POWER
2
16
R1
Vss 1
Vdd 2 22R
1 15
Vo 3
Q1
RS 4 LCD CONN ORIENTATION FROM FRONT
R/W 5
E 6
D0 7
BC327-25
D1 8
D2 9
D3 10
D4 11
D5 12
D6 13
D7 14
LED A 15
LOGIC GND
LED K 16
To enhance viewing, please print to A3
AP16369/3 Front Panel PCB Schematic (Microcontroller & LCD)
Cambridge Audio Azur 840A Amplifier
COL 1 COL 2
SW1 SW2
SW-TACT SW-TACT
INPUT 1 INPUT 2
RS232 TX
SW5 SW6
Q4
R13
SERIAL TX 232
SW-TACT SW-TACT
22K
INPUT 5 INPUT 6
BC337
SW9 SW10
RS232 TX
SW-TACT SW-TACT
MODE ON/STBY
+5V
C7
100nF
LOGIC GND
SHIFT REG DECOUPLE
SPEAKER TEST
RS SHIFT REG ENABLE
C5
E
2
D SERIAL DATA 22pF
3
CLK SERIAL CLOCK
1
STB X1
15
C6
OE SHIFT REG ENABLE
CRYSTAL
R15 LOGIC GND 22pF
FREQ=20MHz
10K
U2
BLOCK
IR CONTROL
LOGIC GND
PIC TX
+5V
HUB DATA
SERIAL IN FROM A-BUS HUB BOARD
HUB CLOCK
BC327-25
R7
Q8
2K2
R3
2K2
PRESET 20K 3296W
PR1
2
D4
10U 16V
CW 1N4148
R6
1K1
C24
D8
D5 D6
BZX79C2V7 500MW
Q2 1N4148 1N4148
1K1
R8 BC337
COL 3 COL 4
SW3 SW4
SW-TACT SW-TACT
ROW 1
INPUT 3 INPUT 4
SPEAKER TEST
SW7 SW8
PHONES DETECT
OVERLOAD
CLIP DETECT
SW-TACT SW-TACT
DC OFFSET
ROW 2
INPUT 7 TAPE MON
OVER TEMP
MAINS FAIL
SW11
POSITION FOR
EXTRA SWITCH
SW-TACT
spare ROW 3
SPEAKER SELECT
+5V
R14
10K
U1
1
MCLR/VPP RB7/PGD
40
2
RA0/AN0 RB6/PGC
3 39
RA1/AN1 RB5
4 38
RA2/AN2 RB4
37
5
RA3/AN3/VREF RB3/PGM
6 36
RA4/T0CKI RB2
7 35
RA5/AN4/SS RB1 CLIP DETECT
34
8
RE0/RD/AN5 RB0/INT OVERLOAD
33
9
RE1/WR/AN6 VDD
10 32
RE2/CS/AN7 VSS
11 31
VDD RD7/PSP7 OVER TEMP
30
12
DC OFFSET
VSS RD6/PSP6
13 29
OSC1/CLKIN RD5/PSP5 MAINS FAIL
14 28
OSC2/CLKOUT RD4/PSP4 PHONES DETECT
27
15
SERIAL RX 232
RCO/T1OSO/T1CKI RC7/RX/DT
16 26
RC1/T1OSI/CCP2 RC6/TX/CK SERIAL TX 232
17 25
RC2/CCP1 RC5/SDO SERIAL DATA
24
18
RC3/SCK/SCL RC4/SDI/SDA SERIAL CLOCK
23
19
RD0/PSP0 RD3/PSP3 SERIAL STROBE
20 22
RD1/PSP1 RD2/PSP2
21
SERIAL CONTROL OUT
PIC16F877A
PORT B HAS WEAK PULLUPS
RB4-RB7 HAS INTRPT ON CHANGE
100N CERAMIC
D7
R17
1N4148
10K
R4
4K7
0 = BRIGHT
TRISTATE= OFF
BC337
1= DIM
Q5 LOGIC GND
R18
FRONT PANEL GROUNDING
2K2
TRISTATE LED CONTROL
+5V +15V
ON/STBY LED
D2
LOGIC GND
BLUE LED
C19 C18 C21 C15 C16 C17 C22
100n 100n 100n 100pF 100pF 100n 100n
PIC INPUT EMC CAPS
LOGIC GND
IR IN (FROM RECEIVER ON PREAMP BOARD)
R23
10R
R24
10R
+5V C10
100n CER
C3
C11
100n CER
C1
10U 16V
100n
LOGIC GND
FRONT PANEL GND
LOGIC GND
IR IN (FROM JACK & PHONO ON HUB PCB)
PROGRAM_CLOCK
Q6
PROGRAM_DATA
Programming Signals
To ABUS Hub PIC
MCLR HUB BC337
PGM
LOGIC GND
100N CERAMIC
RS232 TX
C9
C23
P2 RS232 RX
PAD
P3
PGM
10R MCLR HUB
R10
47R
R16
PAD PROGRAM_DATA
PROGRAM_CLOCK
BLOCK
LOGIC GND PIC TX
FRONT PANEL GND
LOGIC GND HUB DATA
HUB CLOCK
SERIAL IN FROM A-BUS HUB BOARD
CN1
1
2
3
4
5
6
7
8
9
10
11
12
FFC 12WAY
CONNECTOR TO PREAMP PCB
ROT1
1
A SW
2
B SW
3
C GND
4
FIX1
5
FIX2
NOBLE16ENCODER
R19
10K
1
TX
2
RX
3
RS232 GND
4
IR IN
5
IR GND
6
7
8
CN3
9
10
11
12
13
FFC 13WAY
RS232 & IR CABLE TO HUB PCB
8