JVC FS-A52, Service Manual

Page: 41 / 82

1-41
FS-A52
2. Pin function
Pin
No.
Symbol
I/O
Function
Function
I/O
Symbol
Pin
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
FM IN
AM MIX
FM IF
AM IF
GND
TUNED
STEREO
VCC
FM DET
AM SD
FM VSM
AM VSM
MUTE
FM/AM
MONO/ST O
I
I/O
O
O
I
O
I
I
I
O
O
III
I
I
This is an input terminal of FM IF
signal.
This is an out put terminal for AM
mixer.
Bypass of FM IF
Input of AM IF Signal.
This is the device ground terminal.
When the set is tunning,this terminal
becomes "L".
Stereo indicator output. Stereo "L",
Mono: "H"
This is the power supply terminal.
FM detect transformer.
This is a terminal of AM ceramic filter.
Adjust FM SD sensitivity.
Adjust AM SD sensitivity.
When the signal of IF REQ of IC121(
LC72131) appear, the signal of FM/AM
IF output. //Muting control input.
Change over the FM/AM input.
"H" :FM, "L" : AM
Stereo : "H", Mono: "L"
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
OSC BUFFER
AM OSC
REG
AM RF
AFC
AM AGC
O
I
O
I
I
I
AM Local oscillation Signal output.
This is a terminal of AM Local
oscillation circuit.
Register value between pin 26 and pin28
besides the frequency width of the
input signal.
AM RF signal input.
This is an output terminal of voltage
for FM-AFC.
This is an AGC voltage input terminal
for AM
O
O
I
O
AM detection output.
FM detection output.
Mpx input terminal
O
O
I
Left channel signal output.
Right channel signal output.
Input terminal of the Left channel post
AMP.
Input terminal of the Right channel
post AMP.
I
O
Mpx Left channel signal output.
Mpx Right channel signal output.
L OUT
R OUT
L IN
R IN
RO
LO
MPX IN
FM OUT
AM DET
1. Block diagram
ALC
BUFF
AM
OSC
REG
AM
MIX
FM
RF.AMP
AGC
AM IF
DET
SD
COMP
AM
S-METER
FM
S-METER
FM IF
PM
DET
S-CLRVE
AM/FM
IF-BUFF
TUNING
DRIVE
GND
VCC
STEREO
DRIVE
MUTE
DECODER
ANIT-BIRDIE
STEREO
5N
SW
P-DET
PILOT
DET
FF
19k
FF
19k FF
38k
VCO
384KHz
/
2 /
LS
30 29 28 27 26 25 24
23
22 21 20 19 18
17 16
1 2
3
4 6
7
8 9 10
11
12 13
14
15
5
LA1838 (IC1) : FM AM IF amp & Detector, FM MPX decoder