JVC RX-8010RBK Service Manual page 18

RX-8010RBK/ RX-8012RSL
LA1838(IC102) : FM AM IF AMP&detector, FM MPX decoder
1. Block Diagram
30 29 28
REG
AM
ALC AM
MIX
OSC
BUFF
SD
COMP
FM
S-CLRVE
S-METER
PM
FM IF
DET
1 2
2. Pin Function
Pin
Symbol
I/O
No.
FM IN
I This is an input terminal of FM IF
1
signal.
AM MIX
2
O This is an out put terminal for AM
mixer.
3 I
FM IF Bypass of FM IF
AM IF
4 I Input of AM IF Signal.
5 GND
This is the device ground terminal.
6 TUNED
O When the set is tuning, this terminal
becomes "L".
STEREO
7 O
Stereo indicator output. Stereo "L",
Mono: "H"
8
VCC
This is the power supply terminal.
9 FM DET FM detect transformer.
10 AM SD
This is a terminal of AM ceramic filter.
O
11 FM VSM Adjust FM SD sensitivity.
12 AM VSM O
Adjust AM SD sensitivity.
13 I/O
MUTE 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.
14
FM/AM I
"H" :FM, "L" : AM
MONO/ST O
Stereo : "H", Mono: "L"
15
1-18
27 26 25
FM
RF.AMP
AGC
DET
AM IF
AM
S-METER
AM/FM
IF-BUFF
TUNING
DRIVE
GND
5
3 4 6
Function
24 23 22 21
DECODER
ANIT-BIRDIE
STEREO
P-DET
VCO
384KHz
STEREO
DRIVE
VCC
8 9
7 10
Pin
I/O
Symbol
No.
16
L OUT O
17 R OUT O
18 L IN
I
I
19 R IN
20 O
RO
21
LO O
22 IF IN I
23
FM OUT O
24
AM DET O
25 AM AGC I
26 AFC
27
AM RF I
REG
28 O
29 AM OSC
30 OSC BUFFER
O
18
20 19 17
MUTE
5N
SW
FF
FF FF PILOT
38k /
19k 19k LS DET
2 /
11 12 13 14
Function
Left channel signal output.
Right channel signal output.
Input terminal of the left channel post
AMP.
Input terminal of the right channel
post AMP.
Mpx Right channel signal output.
Mpx Left channel signal output.
Mpx input terminal
FM detection output.
AM detection output.
This is an AGC voltage input terminal
for AM
This is an output terminal of voltage
for FM-AFC.
AM RF signal input.
Register value between pin 26 and pin28
desides the frequency width of the
input signal.
This is a terminal of AM Local
oscillation circuit.
AM Local oscillation Signal output.
16
15