NAD C420, Service Manual

Page: 16 / 27

18
U901: LA1837
U303: 74HCT00 U402: NJM78M56FA
1 1A
2 1B
3 1Y
4 2A
5 2B
6 2Y
7 GND
14 V
CC
13 4B
12 4A
11 4Y
10 3B
9 3A
3Y 8
1
INPUT
3
OUTPUT
2
GND
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
ALC
AM
OSC
AM
MIX
AM
RF.AMP
REG
AGC
AM IF
AM
S-METER
TUNING
DRIVE
STEREO
DRIVE
V
CC
V
CC
AM/FM
IF-BUFF
FM
S-METER
S-CURVE
AM IF
FM
DET
GND
FM IF INPUT
AM MIXER
OUTPUT
FM IF INPUT
BYP
ASS
AM IF INPUT
GND
TU-LED
ST
LED
AM-IF OUTPUT
FM DETECT
OR
AM NARROW CF
FM S-METER
OUTPUT
AM S-METER
OUTPUT
MUTE
FM/AM
SWITCH
PILOT
V
CO
SD
COMP
DET
BUFF
DECODER
ANTI-BIRIDE
3 rd 5 th
STEREO
SW
MUTE
VCO
304kHz
FF
38k
P-DET
¯
FM SD ADJ OSC REG AM RF INPUT AFC AM
AGC
AM DETECT
OR
INPUT FM DETECT
OR
OUTPUT MPX IUTPUT MPX OUTPUT MPX OUTPUT AM STEREO L INPUT AM STEREO R INPUT L-OUT R-OUT
FF
19k
FF
19k
PILOT
DET