NAD
SER
VICE
MANUAL
C 372
STEREO
AMPLIFIER
C
37
2
STEREO AMPLIFIER
May 2005
ALIGNMENT PROCEDURE (C372)
I.
INITIAL ADJUSTMENT (No load connected)
A. OUTPUT OFFSET VOLTAGE
1. Connect a DC Millivoltmeter between TP303 and TP304, then adjust VR303
(50kohms) to get a reading of
0V +/-3V so at the speaker terminals of 0V+/-30mV.
2. Connect a DC Millivoltmeter between TP403 and TP404, then adjust VR401
(50kohms) to get a reading of
0V +/-3V so at the speaker terminals of 0V+/-30mV.
B. IDLING CURRENT
1. Connect a DC Millivoltmeter to TP301 and TP302, then adjust VR302 (500ohms)
for 5-6mV reading on meter.
2. Connect a DC Millivoltmeter to TP401 and TP402, then adjust VR402 (500ohms)
for 5-6mV reading on meter.
3. Leave power "ON" for a minimum of 5 minutes.
C. ISC SENSITIVITY
Connect a DC Millivoltmeter to TP701 and TP702, then adjust VR701 (47kohms)
between 50mV to -100mV.
II. FINAL ADJUSTMENT
Repeat procedure A and B for offset voltage and idling current alignment respectively.
VR303
VR302
TP303 TP304
TP302
TP301
VR402
VR401
TP402
TP403 TP404
TP401
LEFT CHANNEL
RIGHT CHANNEL
MAIN BOARD
B649
EC B
2SB649
2SD669
PORT2/0
PORT2/1
PORT2/2
PORT2/3
PORT2/4
PORT2/5
PORT2/6
PORT2/7
VCC
XTAL2
XTAL1
PORT3/1
PORT3/2
PORT3/3
PORT0/0
PORT0/1
PORT0/2
GND
1
2
3
4
5
6
7
8
910
11
12
13
14
15
16
17
18
Z86C0812PSC
1
2
3
4
5
6
78
9
10
11
12
13
14
GND
VCC
74LS00
IC902:
QP0 QP1 QP2 QP3 QP4 QP5 QP6 QP7
1
2
3
4567
8
9
10
11
12
13
14
15
16
8-STAGE SHIFT REGISTER
8-BIT STORAGE REGISTER
3-STATE OUTPUTS
D
CP
STR
OE
QS1
QS2
VCC
GND
CD4094
2SA872
2SA1015
2SC1815
A970
EC B
K369
DG S
2SK369
SG V
IS1U621L
R103
470 MF
R105
470 MF
C102
100p
C103
100p
R107
470 MF
R109
470 MF
R111
470 MF
C104
100p
C105
100p
C106
100p
R113
470 MF
R115
470 MF
R118
470 MF
C107
100p
C108
100p
C109
100p
R116
1M
R114
1M
R112
1M
R104
1M
R106
1M
R108
1M
R110
1M
6
5
4
RL6B
6
5
4
RL7B
6
5
4
RL8B
6
5
4
RL9B
6
5
4
RL10B
6
5
4
RL11B
6
5
4
RL12B
RCA1C
CD
RCA1E
VIDEO
RCA2A
AUX
RCA2C
TUNER
RCA3A
REC2
RCA3C
TAPE1
RCA3E
REC1
RCA2E
TAPE2
RCA4A
PREOUT1
RCA4B
PREOUT 1
RCA4E
PREOUT 2
RCA4F
PREOUT 2
R203
470 MF
R205
470 MF
C202
100p
C203
100p
R207
470 MF
R209
470 MF
R211
470 MF
C204
100p
C205
100p
C206
100p
R213
470 MF
R215
470 MF
R217
470 MF
C207
100p
C208
100P
C209
100P
R216
1M
R214
1M
R212
1M
R204
1M
R206
1M
R208
1M
R210
1M
3
2
1
RL6A
3
2
1
RL7A
3
2
1
RL8A
3
2
1
RL9A
3
2
1
RL10A
3
2
1
RL11A
3
2
1
RL12A
RCA1D
CD
RCA1F
VIDEO
RCA2B
AUX
RCA2D
TUNER
RCA3B
REC2
RCA3D
TAPE1
RCA3F
REC1
RCA2F
TAPE2
R119
220 MF
1 2 3 4 5 6 7 8 9 10
M102
C372 PREAMP MODULE
+V34
R120
100
C211
8.2P
R219
220 MF
-V34
1
2
3
4
5
6
7
8
CB501
8PIN
L buff out
R buff out
GND
+34V
-34V
Lout
GND
Rout
+V34
-V34
C212
22N
PE
C213
220u
C214
220P
R223
75/FS 0.5W
R222
22K
6
5
4
RL2B
A2
RV5B
1K
C215
220P
RCA4D
MAIN LIN
RCA4C
MAIN RIN
1
2
3
4
5
CB301
5PIN
1 2 3 4 5 6
CB401
6PIN
R753
100
C786
10n/63V
TO LEFT POWER AMP
TO RIGHT POWER AMP
RCA1B
DISC
RCA1A
DISC
R101
470 MF
C101
100p
R102
1M
6
5
4
RL5B
R201
470 MF
C201
100p
R202
1M
3
2
1
RL5A
C111
22N
PE
C112
220u
C113
220P
R124
75/FS 0.5W
R123
22K
3
2
1
RL2A
B1
A1
RV5A
1K
C114
220P
R117
1M
R218
1M
4
5
6
SW2B
SOFT
V34R
CLLED
BRIDGELED
8
RL5C
12V
8
RL6C
12V
8
RL7C
12V
8
RL8C
12V
8
RL9C
12V
8
RL10C
12V
8
RL11C
12V
8
RL12C
12V
D730
1N4148
D731
1N4148
D732
1N4148
D733
1N4148
D734
1N4148
D735
1N4148
D736
1N4148
V5
IR IN
IR out
+12V
TAPE1
TAPE2
TUNER
AUX
VIDEO
CD
DISC
A SPEAKER ON
IRMUTE
B SPEAKER ON
MAIN ON
7
8
9
SW3C
BRIGDE
1
2
3
4
5
6
7
8
9
10
CB906
10PIN
1
2
3
4
5
6
7
8
9
10
CB907
10PIN
+12V
R126
100K
R226
100K
V34R
PR
IRMUTE
+5V
+12V
R127
200
R227
200
C501
220u/25
R506
3K32 MF 1%
R507
750 MF 1%
R504
390 MF 1%
R505
180 1%
B1
A1
RV1A
10KA
B1
A1
RV2A
10KA
C507
22n 2%
C508
0.1u 2%
R501
1K5 MF 1%
R502
390 MF 1%
C503
0.22u 5%
C504
0.97u 5%
C509
470P
RV4A
20K MN
C601
220u/25
R606
3K32 MF 1%
R607
750 MF 1%
R604
390 MF 1%
R605
180 1%
A2
RV1B
10KA
A2
RV2B
10KA
C607
22n 2%
C608
0.1u 2%
R601
1K5 MF 1%
R602
390 MF 1%
C603
0.22u 5%
C604
0.97u 5%
C609
470P
RV4B
20K MN
R503
5K1
R603
5K1
ON
OFF
OFF
ON
BALANCE
POT
BALANCE
POT
BASS
POT
BASS
POT
TREBLE
POT
TREBLE
POT
RV3A
10KA
RV3B
20KA
1
2
3
4
5
6
7
8
CZ501
8PIN
VOL-UP
TONE RIN
TONE ROUT
TONE LOUT
1 2 3 4 5 6 7 8 9 10
M501
C372 PREAMP MODULE
R509
100
C511
44P
-34V
R511
590
1%
MF
R609
590
1%
MF
MD1C
R523
2K2
R521
2K2
R525
2K2
R520
2K2
R524
2K2
R522
2K2
C520
4u7
C521
4u7
Q502
C1815
Q501
A1015
Q504
C1815
Q503
A1015
MOTOR
M
VOLUME CONTROL
5V
1
2
3
4
CB502
4PIN
VOL-DN
TONE-LIN
C602
10n
C502
10n
+34V
-34V
+34V
+34V
TONE&VOL BAL
4
5
6
SW4B
DEFEAT
1
2
3
SW4A
DEFEAT
C522
0.1u
-34V
R513
10M
R514
1.6 MF
R614
1.6 MF
R515
10K
R615
10K
Q804
2SK209
R810
18K
R801
1K
R808
10
R804
10
R802
1K
R805
1M
R806
430
R809
1K
R803
1K5
R807
560
Q806
2SA1225
Q801
2SA1312
Q802
2SC3324
Q805
2SC3324
Q803
2SC2983
C802
1N
C801
47pF
Q809
2SK209
R818
18K
R811
1K
R820
10
R819
10
R812
1K
R814
1M
R815
430
R817
1K
R13
1K5
R816
560
Q812 2SA1225
Q807
2SA1312
Q808
2SC3324
Q810
2SC3324
Q811
2SC2983
C804
1N
C803
47pF
1
2
3
4
5
6
7
8
9
10
P801
10PIN
VEE
VCC
VCC
VEE
VCC
VEE
R821
220
C805
22p
C808
22p
R822
220
C806
0.1uF
C807
0.1uF
C809
0.1uF
C10
0.1uF
1 2 3
SW3A
4 5 6
SW3B
R11
10K
+12V
R12
22K
R13
10K
-V34
PR
SP B
SP A
MAIN ON
BG_O
BG_I
BG_S
BG_O
BG_I
BG_S
JIRA
IR IN
JIRB
IR OUT
STR
1
D
2
CLK
3
OE
15
Q1
4
Q2
5
Q3
6
Q4
7
Q5
14
Q6
13
Q7
12
Q8
11
QS
9
QS
10
VCC
16
GND
8
IC905
4094
STR
1
D
2
CLK
3
OE
15
Q1
4
Q2
5
Q3
6
Q4
7
Q5
14
Q6
13
Q7
12
Q8
11
QS
9
QS
10
VCC
16
GND
8
IC904
4094
C902
20P
C903
20P
X901
12MHz
C901
0.1u
C915
0.1u
+5V
C VI TU AU T2 T1 DI
LD902
CD
LD904
AUX
LD901
DISC
LD905
TUNER
LD903
VIDEO
LD907
TAPE1
LD906
TAPE2
R924
4K7
R903
1K
R923
2K2
Q913
A1015
P24
1
P25
2
P26
3
P27
4
VCC
5
X2
6
X1
7
P31
8
P32
9
P33
10
P00
11
P01
12
P02
13
GND
14
P20
15
P21
16
P22
17
P23
18
IC902
Z86C0812PSC
Q901
C1815
Q902
C1815
Q903
C1815
Q904
C1815
Q905
C1815
Q906
C1815
Q907
C1815
R922
4K7
R920
4K7
R918
4K7
R916
4K7
R914
4K7
R912
4K7
R910
4K7
C906
10n
C907
10n
C908
10n
C909
10n
C910
10n
C911
10n
C912
10n
CVI
TU
AU
T2
T1
DI
CD
VIDEO
TUNER
AUX
TAPE2
TAPE1
DISC
CD VIDEO
TUNER
AUX
TAPE2 TAPE1
DISC
R909
4K7
R911
4K7
R913
4K7
R915
4K7
R917
4K7
R919
4K7
R921
4K7
R939
10K
R906
10K
R940
10K
GREEN
GREEN
GREEN
GREEN
GREEN
GREEN
GREEN
R935
100
R936
100
R937
10K
8
1
2
3
4
5
6
7
12
11
10
9
13
14
IC901
74LS00
+5V
+5V
+5V
+5V
R925
10K
+5V
V34R
+12V
K907VIDEO
K906 AUX
K904
TAPE2
K905 CD
K903 TAPE1
K901 DISC
K902 TUNER
V S G
IC903
IS1U621L
C904
10u
+5V
K908
B
R930
6K8
R933
2K2
R928
0
Q910
C1815
LD911
BRIDGE
LD912
SOFT
LD909
B
A
A SPEAKER ON
A
SPEAKER
ON
MUTE blink
V34R
A SPEAKER ON
TAPE1
TAPE2
TUNER
AUX
VIDEO
CD
DISC
+5V
REMOTE
REMOTE
CONTROLLER
KEYBOARD
B SPEAKER ON
IRMUTE
B SPEAKER ON
B
LD908
A
BSPEAKER
ON
Q908
C1815
R908
4K7
C913
10n
R907
4K7
Q909
C1815
R904
4K7
C914
10n
A
R905
4K7
BRLED
CLLED
IRMUTE
B
BRLED
CLLED
PR
PR
K909
A
15
9
3
BLINK
+5V
R927
330
R934
820
Q912
C1815
D909
1N4148
D912
1N4148
LED910
LED2
GRN
RED
GRN
IR OUT
IR IN
+5V
IR OUT
IR IN
+12V
D907
6V8
+12V
R929
22K
LED BOARD
P ON/OFF
D908
1N4148
D906
1N4148
D910
1N4148
D911
1N4148
P12V
TO PHONE BOARD CZ706
1
2
3
4
5
6
7
8
9
10
CZ906
10PIN
1
2
3
4
5
6
7
8
9
10
CZ907
10PIN
1 2 3 4
CZ502
4PIN
V34R
Q914
C1815
R941
10K
R943
4K7
P ON/OFF
R944
2K2
R945
2K2
Q916
C1815
R901
200
R900
1K
+5V
R902
1K
Q915
A1015
+5V
+5V
NC
1
NC
2
NC
3
Vss
4
SDA
5
SCL
6
NC
7
Vcc
8
IC906
24C00
R931
10K
+5V
C905
47uF/25V
R938
330
R926
22
R798
330
R610
15K
R510
15K
R121
562
R221
562
/2SD1815
/2SD1815
/2SB1215
/2SB1215
C372 PREAMP MODULE
C372 PREAMP MODULE