Adcom GTP-740, Service Manual

Page: 34 / 58

34
GTP-740
OUT
GND
IN
KEYBOARD ASSEMBLY
U508: NJM78L05A
TUNER ASSEMBLY
U205: NJM78L05A
22 23 24 14 19 17 16 4
8
15
9
12
7 6 5 3 2 1 10 13 11 18 20
21
IF
Butter
IF
Butter
FM - IF Q. D
Post
Amp
LED
Driver
S-Meter
Det
AGC
Narrow
S-Meter
AM - IF MIX RF
Reg OSC
OSC
Butter
GND
Vcc
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
TUNER ASSEMBLY
U202: LA1266
1
AM
input
FM
input
Composite
amp
output
Separartion
adjust
Post
amp
output
Post
amp
input
Post
amp
input
Post
amp
output
Vcc-ON
muting
FM/AM
changeover
Muting
output
GND
Stereo
indicator
Changeover
mute Muting
Pilot sync
detector
filter
Pilot sync
detector
filter,
VCO stop
PLL
input
Loop
filter
Loop
filter OSC
Power
supply
Muting
FM AM Change
2 3 4 5 6 7 8 9 10 11
22 21 20 19 18 17 16 15 14 13 12
Decoder
Muting Control
FM AM Changeover
Muting
Output
Vol Reg
Symmetrical
-Reactance
Circuit
OSC
VCO Stop
FF
Phase
Comparator
Pilot Det
Vcc On
Muting
FF
FF
38kHz
FF
19kH<90˚
FF
19kH<0˚
Stereo
Switch
Lamp
Driver
Trigger
TUNER ASSEMBLY
U204: LA3401
IC BLOCK DIAGRAM