XR-1800RD - Sony Car Audio Service Manual (repair manual). Page 21

Read Sony XR-1800RD Service Manual online

21
5-7.
IC  PIN  FUNCTION  DESCRIPTION
 MAIN BOARD  IC1  MN1884820SF (SYSTEM CONTROLLER)
Pin No.
Pin Name
I/O
Description
1
TUNMUT
O
FM audio signal muting control output terminal    “H”: muting on
2
AMPON
O
Standby control signal output to the power amplifier  (IC500)    “L”: standby
3
ILLON
O
Power supply on/off control signal output terminal at the liquid crystal display driver (IC900),  
illumination lamp and back light lamp    “H”: power on
4
PW ON
O
Main system power supply on/off control signal output terminal    “H”: power on
5
AMPMUTE
O
Muting control signal output to the power amplifier  (IC500)    “L”: muting on
6
NIL
I
Not used (fixed at “L”)
7
VDD1
Power supply terminal (+5V)
8
X IN
I
Main system clock input terminal (8 MHz)
9
X OUT
O
Main system clock output terminal (8 MHz)
10
GND
Ground terminal
11
XT IN
I
Sub system clock input terminal (32.768 kHz)
12
XT OUT
O
Sub system clock output terminal (32.768 kHz)
13
EX2
I
Connected to ground
14
RESET
I
System reset signal input from the reset signal generator (IC50) and reset switch (S2)
“L” is input for several 100 msec after power on, then it changes to “H”
15
RDSCKI
I
Serial data transfer clock signal input from the RDS decoder (IC150)
16
BU IN
I
Battery detect signal input terminal    “H”: battery on
17
KEYACK
I
Input of acknowledge signal for the key entry    Acknowledge signal is input to accept function 
and eject keys in the power off status    On at input of “H”
18
VOLSO
O
Serial data output to the electrical volume  (IC450)
19
VOLCKO
O
Serial data transfer clock signal output to the electrical volume  (IC450)
20
VOLCE
O
Chip enable signal output to the electrical volume  (IC450)
21
TAPE MUTE
O
Tape muting on/off control signal output terminal    “H”: tape muting on    Not used (open)
22 to 24
NCO
O
Not used (open)
25
AMS ON
O
Tape auto music sensor control signal output terminal
“L” is output to lower the gain for audio level at FF/REW    Not used (open)
26
ATA ON
I
Not used (fixed at “H”)
27
TAPE IN
I
Tape in detection switch (S903) input terminal    “L”: tape in
28
FF-REW IN
I
FF/REW detection switch (S902) input terminal    “L”: FF/REW mode
29
N/R
I
Tape direction switch (S901) input terminal
“L: reverse direction, “H”: forward direction
30
RDSSI
I
Serial data input from the RDS decoder (IC150)
31
AD ON
O
Power supply on/off control signal output for the A/D converter    “L”: power on
32, 33
NCO
O
Not used (open)
34
CM ON
O
Capstan/reel motor (M901) drive signal output terminal    “H”: motor on
35
TAPE ON
O
Tape system power supply on/off control signal output terminal    “H”: tape on
Not used (open)
36
ACC IN
I
Accessory detect signal input terminal    “L”: accessory on
37
PLLSI
I
PLL serial data input from the FM/AM PLL (IC121)
38
BEEP
O
Beep sound signal output terminal
39
PLLSO
O
PLL serial data output to the FM/AM PLL (IC121)
40
PLLCLK
O
PLL serial data transfer clock signal output to the FM/AM PLL (IC121)
41
PLLCE
O
PLL serial chip enable output to the FM/AM PLL (IC121)
42
LCD INH
O
Blank indicate control signal output to the liquid crystal display driver (IC900)                                
“L”: no display
Page of 34
Display

Click on the first or last page to see other XR-1800RD service manuals if exist.