Adcom GTP-740 Service Manual page 34

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