NAD S250 User manual

SERVICE MANUAL
S250
S250
FIVE CHANNEL
POWER AMPLIFIER
FIVE CHANNEL
POWER AMPLIFIER

CONTENTS
FRONT PANEL / REAR PANEL VIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
ALIGNMENT PROCEDURE / ALIGNMENT POINTS . . . . . . . . . . . . . . . . . . . . . . . . 5
WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
PCB LAYOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8
SCHEMATIC DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-11
ELECTRICAL PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-14
EXPLODED VIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
EXPLODED VIEW PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
PACKING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
SERVICE SAFETY PRECAUTIONS
1. Replacing the Fuses
CAUTION: FOR CONTINUED PROTECTION AGAINST THE RISK OF FIRE REPLACE ONLY
WITH SAME TYPE OF FUSE.
REFERENCE NO. PART NUMBER DESCRIPTION
PSU Board
F1*AH 5120-0506-0 12.5A 250V Time Lag 6.3x32mm UR
F1*C 5120-0025-0 6.3A 250V HBC Time Lag 5x20mm SEMKO/VDE
Amp Board
F1-F2*AH 5120-0040-0 6.3A 250V Time Lag 5x20mm UL
F1-F2*C 5120-0025-0 6.3A 250V HBC Time Lag 5x20mm SEMKO/VDE
NOTE:
*AH : North American version only
*C : European version only
2. Safety-check out (North American model only)
Before returning the product to the customer, make leakage current or resistance measurements
to determine that exposed parts are acceptably insulated from the supply circuit.
Parts marked with the symbol are critical with regard to the risk of fire and electric shock.
Replace only with parts recommended by the manufacturer.
!
!
!
!
!

1. LEVEL CONTROL 5. 12V TRIGGER INPUT
2. INPUT JACK 6. SPEAKER TERMINALS
3. SOFT CLIPPING SWITCH 7. AC INLET
4. AUTO TRIGGER SWITCH
Five Channel Power Amplifier S250
34
1 2
NA D
SOFT CLIPPING
PROTECTION
1. POWER SWITCH 3. PROTECTION INDICATOR
2. POWER INDICATOR 4. SOFT CLIPPING INDICATOR
FRONT PANEL / REAR PANEL VIEW
FRONT PANEL CONTROLS
The graphic symbol of a lightning flash with an arrow point
within a triangle signifies that there is dangerous voltage
within the unit and it posses a hazard to anyone removing
the cover to gain access to the interior of the unit. Only
qualified service personnel should make such attempt.
The graphic symbol of an exclamation point within
an equilateral triangle warns a user of the device
that it is necessary to refer to the instruction
manual and its warnings for proper operation of
the unit.
REAR PANEL CONNECTIONS
AC MAINS INPUT
120V
TRIGGER IN
+12V
AUTO TRIGGER
2
1
3 4 5
67
1

SPECIFICATIONS
Specifications are measured in accordance with IHF standard IHF-A-202, 1978.
NOMINAL LIMIT
1. THD #0.02% #0.03%
2. Continuous Power Output 8 ohms $125W $100W
20kHz, 5 ch. for 8 ohms, 4 ch. for 4 ohms) 4 ohms $125W $100W
3. Clipping Power $135W $110W
4. S/N Ratio A-wtd $96dB $93dB
maximum) Audio BPF $89dB $86dB
5. Frequency Response 0 ~ -0.1dB 0 ~ -0.25dB
6. Input Sensitivity 100 ± 2 mV 100 ± 3 mV
maximum)
7. Channel Separation 1kHz $77dB $70dB
20kHz $67dB $50dB
8. Soft Clipping
Output Reduction 0.4 ~ 0.6 dB 0.3 ~ 1.0 dB
THD 5 ~ 6.5% 4 ~ 10%

R44 R40 R41
TP1
TP2
RELAY
R27
J1
R45
IDLE CURRENT ALIGNMENT FOR EVERY POWER AMPLIFIER MODULE
1. Remove the load and the input signal.
2. Connect a digital voltmeter between TP1 and TP2.
3. Switch the amplifier on and, after one minute, adjust R27 to obtain a reading of
5mV ±0.5mV.
4. Leave power on for 3 minutes to allow the idle currents to stabilize. Re-adjust R27
as necessary to obtain a reading of 4.4mV ±0.5mV.
ALIGNMENT PROCEDURE
ADJUSTMENT POINTS

WIRING DIAGRAM
J2
J3 +
J4 -
+
J1
1
CHANNEL 5
AMP BOARD
1
J2
J3 +
J4 -
+
J1
1
CHANNEL 4
AMP BOARD
1
J2
J3 +
J4 -
+
J1
1
CHANNEL 3
AMP BOARD
1
J2
J3 +
J4 -
+
J1
1
CHANNEL 2
AMP BOARD
1
J2
J3 +
J4 -
+
J1
1
CHANNEL 1
AMP BOARD
1
PSN PSL
S1
S2
S3
S4
S5
S6 M1
M2
M3
M4
M5
M6
SS1 SS2
1
11
1
1
1
J18 J17 J19
J5 J4 J3 J2 J1
RED
BLK
BLU
BRN
WHT
YEL
GRN-YEL (230V ONLY)
GRY
ORN
VIO
GRY
ORN
VIO
RED
BLK
BLU
BRN
WHT
YEL
YEL
YEL
BRN (230V) BRN (230V)
BRN
BLU
BLU (230V)
BLU (230V)
RED
WHT
BLK
RED
RED
WHT
BLK
RED
RED
WHT
BLK
RED
RED
WHT
BLK
RED
RED
WHT
BLK
RED
S1 S2 S3 S4 S5 S6
M1 M2 M3 M4 M5 M6
RED
BLK BLU
BRN WHT —
120V 230V
120V
230V
BRN BLK WHT RED BLU
—
BLK WHT RED BLU BRN —
BLK WHT RED BRN BLU
—
MAIN
TRANSFORMER
STANDBY
TRANSFORMER
BLK RED BLK RED BLK RED BLK RED BLK RED
LEN
AC INLET
EMI FILTER
POWER SWITCH
STANDBY
TRANSFORMER
MAIN
TRANSFORMER
PSU BOARD
TRIGGER
SWITCH
BOARD
PWR LED
BD
PROT/SC
LED BD
J26
J27
J28
J22
J24
J25
BLU (120V)
BRN (120V)
CHASSIS

PSU BOARD - COMPONENT SIDE
PSU BOARD - SOLDER SIDE

PCB LAYOUT
AMP BOARD - COMPONENT SIDE AMP BOARD - SOLDER SIDE

F1
T6.3A 250V SEMKO/VDE
SW1
R102
33
C2
0.1u
C3
0.1u
C8
33000uF/80V
C1
47nF 250V
C4
0.1u
C6
0.1u
R101
6R8 1W
R106
1K
R103
1K
C5
0.01u
C7
0.01u
1 2 4
3
5
M101
LINE FILTER FOR 230V VERSION ONLY
1 2
AC1
AC INLET
POWER SWITCH
T1
MAIN POWER TRANSFORMER
D1
DIO-BRIDGE1
J1 J2 J3 J4 J5
J6
J7 J8 J9
J10
1 2
3
U102A
HEF4011
4
5 6U102B
HEF4011
7
8 9
10
U102C
HEF4011
11
12 13
14
U102D
HEF4011
J2
DC IN R107
1K
SW2
AUTO POWER SW
R108
10K
R104 560
T102
STANDBY TRANSPORWER
R105
1R
C102
470u/25V
3
2
1
U103
78L05
C103 0.1u
+5V
C12
10u/100V
C11
10u/100V
R12
750R
R11
750R
R8
3K9 2W
D105
5V6
D11
IN4745A
D10
IN4745A
D12
IN4745A
D13
IN4745A
R10
3K9 2W
R6
300R FP
R1
300R FP
R9
390R
5 2 4 1 6 3
SW3
SOFT CLIPPING
R7
10K 2W
LED1
POWER
LED2
LED CLIP
LED3
PROTECT
Q102 2SC1815
R112
10K
C9
33000uF/80V
R2
1R FP
R3
1R FP
R4
10K 2W
R5
10K 2W
C10 4.7u
V+ V-
V+ V- V+
1 2 34
5 6
U101
TLP3063
Line Filter
NEUTRAL
LIVE
FUSE
T12.5A 250V UL/CSA
CH1-5
V+ +VCTL V- -VCTL GND
100V
IN OUT
GND
NP NP
1/2W
1/2W
ON OFF
R111 560R
+5V
MAIN TRANSFORMER
120V
230V
M1 M2 M3 M4 M5 M6
BRN BRN
BLK BLK
WHT
WHT
BLU RED
RED BLU
STANDBY TRANSFORMER
120V
230V
S1 S2 S3 S4 S5 S6
BLK BLK
WHT WHT
RED
RED
BLU BRN
BRN BL U
D202
IN4148
D103
IN4148
D104
IN4148
D3
IN4004
D2
IN4004
PROTECT
LED
POWER LED PCB
CILP PROTECT PCB
+VCTL -VCTL
CLIP SWITCH PCB
Q101
TRIAC 20A
KA
A A
K
KDGND
DGND
+5V
POWER SUPPLY

J1-1 J1-2 J1-3 J1-4 J1-5 J1-6 J1-7 J1-8 J1-9
J1-10
F1
T6.3A 250V
F2
T6.3A 250V
C24
0.1
C25
0.1
R63
1R
Q26
MPSA06
Q25
2N6488
R65
7K5
C33
100u/16V
D19
IN4744
D20
IN4744
C34
100u/16V
R66
7K5
Q27
MPSA56
Q28
2N6491
R64
1R
R67
2K2
R68
2K2
C35
470u/16V
C36
470u/16V
1
6
7
+
-
U2A
LM339
2
4
5+
-
U2B
LM339
11 10
13
+ -U2C
LM339
14
8
9+
-
U2D
LM339
12
3
U2E
LM339
4
8
U1C
NE5532
C37
0.1u
C38 0.1u
C28 0.1u
C27
0.1u
R57
1M
R58
200K
D17
IN4004
C13
22u/25V
20%
D16
IN4148
R54
20K
Q1
2N4403
R56 1M
R61 20K
R55
200K
R62 20K
R83
2K21 1%
R72 51K
ILIMIT
R69
100K
R70
200K D15
IN4148
C18
22u/25V
D18
IN4148
+12V +12V
-12V
+12V
AMPOUT
R76
51K
C20
22u/25V
D22
IN4148
D21
IN4148
R73 20K
R75
510K
R74
20K
+12V
R80 825R
R79
1K
R81
15K 1%
R78
2K21 1%
R77
11K5 1%
R85 100R
+12V
PROTECT
1W
FP
20%
2%
1W
FP
V+
V-
20% 20% 50V 50V
50V 50V
1% NTC
1/2W FP
20%
20%
C26 R60 D14 D23 4
4 4 4
PROTECT LED
COM
V-
V+
4 4
INSERT BUSS WIRE JUMPER 401-20003-00 FOR R22. R50
SIGNIFIES SAFETY CRITICAL COMPONENTS
REFER TO THE SAFETY INFORMATION SECTION OF THE
SERVICE MANUAL FOR COMPLETE INFORMATION. COMPONENTS NOT INSTALLED: C10. C12. C14. C15. C21. C26. D1. D2. D13. D14. D23. D24 R8. R20. R49. R52. R53. R60. R67. R68 AND R84.
ABBREVIATION: FLAME PROOF = FP. ALL FP DESIGNATED PARTS ARE SAFTEY
CRITICAL REFER TO NOTE 5. ALL CAPACTORS ARE IN MICROFARADS. 10%. 100V. ( DEFAULT VOLTAGE )
ALL RESISTORS ARE IN OHWS 1/4W 5%
7 5.
4
3. 2.
1.
RYDRV
AGND GND
GND AGND
+VCTL
-VCTL GND
+12V
-12V
AGND
AGND
SCHEMATIC DIAGRAM
POWER AMP 1

PROTECT
D90
IN4148
R53
330R
LED1
GREEN
RED
R90
560R
R50
2K2
R84 4K7
RYDRY
C3
1u/50V
1
3 2
+
-
U1A
NE5532
R4
2M2
R5
1K 1%
AMPOUT
R1
1K 1%
J2
C1
120pF R71
50K
C2
0.1u/50V
R3
2M2
Q20
2SC2362K
Q21
2SA1016K
C8 10
C6
10
R86
300
R6
300
100V 100VFP FP
-VCTL +VCTL
Q2
2SC2362K
Q3
2SC2362K
R7
1K5
C4
470pF
R11
182
R12
182
Q5
2SA1016K
Q6
2SA1016K
R17 1K5
R18
100
C5
470pF
R15
182
R16
182
R13 7K15
R14
7K15
Q4
2SA1360
R10
300
R23
100K
C7
68pF D3
IN4148
D4
IN4148
R25 3K9
Q7
2SC3423
R19 300
R24
100K
C9
68pF
R26
1K
C30
0.1u /50V
Q8
2SC3423
R27
1K
D1 D2 R22
JPR
FDBK
R9
100R
-12V
+12V
1% 1%
1%
1%
1% 1%
FP
1% CW
R29
33
Q9
2N4403
R28
20K
C11
22u/25V
20%
R32
100 FP
D5
IN3070 D6
IN3070
R87
680
Q12
2SC3423
R59
100
Q10
MPSA06
Q11
MPSA56
R33 100
R88
680
D7
IN3070
C22
0.01
R82 100
C23
0.01
R20
R8
R31 3K3
D9
IN3070
Q13
2SA1360
D8
IN3070
R30 3K3
C14
C15
Q14
2SC4793
R38
10 FP
R42
10 FP
R34
1K
R36
100 FP
Q16
2SD1975
R35 100
Q15
2SA1837
R37
100 FP
R43
10 FP
R39
10 FP Q17
2SB1317
1 2
3
+
-
R
B
J3
W3
C21
R48
57K6
FDBK
4 6 5 3
2 1
RL1
D12
IN4004
C17
0.1/250V
R47
2R7
R46
57K6
C16
27pF
Q18
2SD1975
R40
0.22R
R41
0.22R
R44
0.22R
R45 0.22
Q19
2SB1317
C39 0.01
D10
IN4004
D11
IN4004
ILIMIT
AMPOUT
V-
V+
W1
FP
1000V
FP
5%
1/2W FP 1/2W
FP
1/2W
20%
2W
RYDRV
TEST
LOCATION 11
5W
5W 5W
5W
1000V
1% 1%
4
4 4 4
7
4
4
4
4
TEST
LOCATION 12
4
1000V
1000V
1000V
1000V
7
-
5
6
+
U1B 5532
20%
CHGND GND
CW
B1-COLOUR
AGNDCHGND CHGND
R51
Jumper
D24
Jumper
GND
FP
GND
C10
4.7uF/100V
GND
-12V
AGND
POWER AMP 2

Location Part Number Descri
p
tion
POWER AMP PCB
PCB ASSEMBLY
1000*AH PCB-N0920C-AMP PCB ASSY POWER AMP
1000*C PCB-N0921C-AMP PCB ASSY POWER AMP
CAPACITORS
C39 150N-103M-5-SS CC 1KV 0.01u 20% RL
C1 150N-121K-5-II CC 1KV 120P 10% RL 5X5
C16 150N-270K-5-II CC 1KV 27P 10% RL 5X5
C4,C5 150N-471K-5-II CC 1KV 470P 10% RL 5X5
C7,C9 150N-680K-5-II CC 1KV 68P 10% RL 5X5
C3 153F-105J-5-NUN CM 50V 1u 5% RL 7.5X11
C22,C23 153H-103J-5-MMN CM 100V 0.01u 5% RL 7X7
C24,C25 153H-104J-5-TXN CM 100V 0.1u 5% RL 10.5X
C2,C27,C28,C30, 153I-104J-5-NMN CM 63V 0.1UF RL
(
7.5X7
)
C37,C38
C17 153R-104J-5-YRM CM 250V 0.1u 5% RL
C35,C36 157D-477M-5-OVK CE 16V 470UF 20% RL
C33,C34 157E-107M-5-KUK CE 25V 100UF 20% RL
C11,C13,C18,C20 157F-226M-5-IUK CE 50V 22uF 20% RL 5X11
C6,C8 157H-106M-5-OVH CE 100V 10u 20% RL
IC
U1 3130-2430-0 IC NE5532 OP AMP PHILIPS
U2 3131-3990-0 IC LM339N QUAD OP-AMP
LED
D1 3700-4807-RG LED RED/GREEN 5.0
RELAY
RL1 4500-0940-0 RELAY 24VDC 30A
RESISTOR
R63,R64 4715-010J-2-P RMF 1/4W 1R 5% AT FP
R38,R39,R42,R43 4715-100J-2-P RMF 1/4W 10R 5% AT FP
R32,R33,R36,R37 4715-101J-2-P RMF 1/4W 100R 5% AT FP
R34 4715-102J-2-P RMF 1/4W 1K 5% AT FP
R77 4715-1152-2 RMF 1/4W 11.5K 1% AT
R7,R17 4715-152J-2-P RMF 1/4W 1.5K 5% AT FP
R11,R12,R15,R16 4715-1820-2 RMF 1/4W 182R 1% AT
R28,R54,R61,R62, 4715-203A-2 RMF 1/4W 20K 1% AT
R73,R74
R78,R83 4715-2211-2 RMF 1/4W 2.21K 1% AT
Location Part Number Descri
p
tion
R50 4715-222A-2 RMF 1/4W 2.2K 1% AT
R3,R4 4715-225A-2 RMF 1/4W 2.2M 1% AT
R6,R10,R19,R86 4715-301J-2-P RMF 1/4W 300R 5% AT FP
R29 4715-330A-2 RMF 1/4W 33R 1% AT
R53 4715-331A-2 RMF 1/4W 330R 1% AT
R25 4715-392A-2 RMF 1/4W 3.9K 1% AT
R84 4715-472A-2 RMF 1/4W 4.7K 1% AT
R72,R76 4715-513A-2 RMF 1/4W 51K 1% AT
R75 4715-514A-2 RMF 1/4W 510K 1% AT
R90 4715-561A-2 RMF 1/4W 560R 1% AT
R46,R48 4715-5762-2 RMF 1/4W 57.6K 1% AT
R87,R88 4715-681A-2 RMF 1/4W 680R 1% AT
R13,R14 4715-7151-2 RMF 1/4W 7.15K 1% AT
R80 4715-8250-2 RMF 1/4W 825R 1% AT
R81 4715-9531-2 RMF 1/4W 9.53K 1% AT
R35,R85 4717-101J-2-P RMF 1/2W 100R 5% AT FP
R30,R31 4717-332A-2 RMF 1/2W 3.3K 1% AT
R65,R66 4718-752J-2-X RMF 1W 7.5K 5% AT METAL
R47 4719-2R7J-2-X RMF 2W 2.7R 5% AT METAL
R9,R18,R59,R82 471G-101A-2-E RMF 0.6W 100R 1% AT
R1,R5,R21,R26 471G-102A-2-E RMF 0.6W 1K 1% AT
R23,R24,R69 471G-104A-2-E RMF 0.6W 100K 1% AT
R56,R57 471G-105A-2-E RMF 0.6W 1M 1% AT
R55,R58,R70 471G-204A-2-E RMF 0.6W 200K 1% AT
R40,R41,R44,R45 474B-R22J-1-E RWR 5W 0.22R 5% AL AL05
DIODES
D5-D9 4803-0700-2 DIODE BAV21 AT
D10-D12,D17 4804-0040-1 DIODE IN4004 AL
D3,D4,D15,D16, 4804-1480-2 DIODE 1N4148 AT
D18,D21,D22,D90
D19,D20 4838-15V6-2 DZ 1W 15V AT TEMIC
TRANSISTOR
Q1,Q9 4854-4030-5 TR 2N4403 PNP HFE100-300
Q7,Q8,Q12 4860-0790-5 TR 2SC3423
(
Y
)
RL
Q16,Q18 4860-0880-5 TR 2SD1975 S.P RL
Q17,Q19 4860-0890-5 TR 2SB1317 S.P RL
Q15 4860-1050-5 TR 2SA1837 100-320 RL
Q14 4860-1060-5 TR 2SC4793 100-320 RL
Q25 4860-5300-5 TR 2N6488 T022B RL
Q28 4860-5310-5 TR 2N6491 T022B RL
Q4,Q13 4860-5320-5 TR 2SA1360
(
Y
)
RL
Q5,Q6,Q21 4860-5330-5 TR 2SA1016K
(
G
)
HFE
Q2,Q3,Q20 4860-5340-5 TR 2SC2362K
(
G
)
HFE
ELECTRICAL PARTS LIST

Location Part Number Descri
p
tion
Q10,Q26 4860-8890-0 TR MPSA06 VCE 80V NS
Q11,Q27 4860-8910-0 TR MPSA56 VCE 80V NS
VR
VR71 4750-9606-1 VR RK09K111 50KA LM=25mm
SVR27 4755-1026-3-14 SVR 1K EVM-31G 6mm DUST
FUSE
F1,F2*AH 5120-0040-0 FU T6.3A 250V 5X20 UL
F1,F2*C 5120-0025-0 FU T6.3A HBC 5X20
MISCELLANEOUS
J1 2101-2181-0 CENTER HEADER 3.96MM
FH1,FH2 4132-1011-0 FUSE HOLDER
TP2,TP1 4132-1071-0 TERMINAL PIN
1007 4134-9241-0 GROUND TERMINAL
R79 8910-0491-0 NTC THERMISTOR 1K
(
B
)
POWER SUPPLY PCB
PCB ASSEMBLY
1100*AH PCB-N0920C-PSU PCB ASSY POWER SUPPLY
1100*C PCB-N0921C-PSU PCB ASSY POWER SUPPLY
CAPACITORS
C103 150F-104K-5-II CC 50V 0.1uF 10% RL 5x5
C4-C7 150N-103M-5-SS CC 1KV 0.01u 20% RL
C2,C3 153R-104J-5-YRM CM 250V 0.1u 5% RL
C102 157E-477M-5-SXK CE 25V 470UF 20% RL
C11,C12 157H-106M-5-OVH CE 100V 10u 20% RL
C10 157H-475M-5-IUC CE 100V 4.7UF 20% RL
C1 8910-0049-0 CAP400V 4700P
C8,C9 8910-0490-0 CE 80V 33000uF 20%
DIODES
D102
4804
-
0010
-
2
DIODE
1N4001
AT
D2,D3 4804-0040-1 DIODE IN4004 AL
D103,D104 4804-1480-2 DIODE 1N4148 AT
D105 4837-5B61-2 DZ 1/2W 5.45-5.73 ROHM
D10-D13 4838-16V6-2 DZ 1W 16V AT TEMIC
D1 4840-7100-0 BRIDGE RECTIFIER MP2540W
TRANSFORMER
T102 1806-3520-0 TRANS EI35 115/230V DC
Location Part Number Descri
p
tion
TERMINAL
0103 2113-1144-0 AC INLET
J17-J19,M1-M6,PSL, 2101-1231-0 SPADE TERMINAL 6.3X0.8
PSN,S1-S6,SS1,SS2,
J1-J5 2101-2171-0 PCB CONN.
(
CENTER 3.96MM
J28 2102-021S-004 2P ST.WAFER
J27 2102-031S-004 3 PIN ST. WAFER
J26 2102-081S-004 WAFER 8P P2.5 ST.
IC
U103 3130-0640-0 IC NJM78L05A 826
U101 3131-6720-0 IC TLP3063 PHOTO TRIAC
U102 3131-6730-0 IC HFE 4011BP QUADRUPLE
RESISTOR
R105 4715-010A-2 RMF 1/4W 1R 1% AT
R2,R3 4715-100J-2-P RMF 1/4W 10R 5% AT FP
R103,R106,R107 4715-102A-2 RMF 1/4W 1K 1% AT
R108,R112 4715-103A-2 RMF 1/4W 10K 1% AT
R1,R6 4715-301J-2-P RMF 1/4W 300R 5% AT FP
R102 4715-330A-2 RMF 1/4W 33R 1% AT
R9 4715-391A-2 RMF 1/4W 390R 1% AT
R104,R111 4715-561A-2 RMF 1/4W 560R 1% AT
R101 4718-6R8J-1-X RMF 1W 6.8R 5% AL METAL
R4,R5,R7 4719-103J-1-X RMF 2W 10K 5% AL METAL
R8,R10 4719-392J-1-X RMF 2W 3.9K 5% AL METAL
R11,R12 471G-751A-2-E RMF 0.6W 750R 1% AT
TRANSISTOR/TRIAC
Q102 4860-0700-5 TR 2SC1815
(
G.R
)
RL
Q101 4860-5350-5 TR BTA26A-600B RL
FUSE
F1*C 5120-0025-0 FU T6.3A HBC 5X20
F1*AH 5120-0506-0 FUSE T12.5A 250V UR
HEATSINKS
1101 5400-9071-0 HEAT SINK
1102 5400-9081-0 HEATSINK FOR BRIDGE
MISCELLANEOUS
0116 5200-3441-0 POWER SWITCH DPST
1108 1660-0700-0 INSULATING BOOT
(
ID=14
)
FL1*C 1806-3519-0 EMI FILTER 20DBAG5
1109 3100-5491-0 INSULATION SHEET 112X27
FH1*AH 4131-9131-0 FUSE HOLDER 6.5MM PITCH

Location Part Number Descri
p
tion
FH1*C 4132-1011-0 FUSE HOLDER
GND1 4132-6221-0 BRACKET, GROUNDING
TRIGGER SW PCB
PCB ASSEMBLY
1200 PCB-N0920C-SW PCB ASSY TRIGGER SWITCH
WAFERS/JACKS
J2 2101-2191-0 DC JACK 3.5
J22 2102-081R-004 8 PIN RIGHT ANGLE WAFER
RESISTOR
J2C 4715-472A-2 RMF 1/4W 4.7K 1% AT
SWITCH
SW02,SW03 5200-3251-0-01 SLIDE SW DPDT VERT 4MM
PROTECT LED PCB
PCB ASSEMBLY
1300 PCB-N0920C-LED PCB ASSY PROTECT LED
WAFER
J24 2102-031R-004 WAFER 3P P2.5 RIGHT
LED
LED3 3700-3538-B LED 3MM FLAT TOP BLUE
LED2 3700-3607-R LED RED 3MM DIA
POWER LED PCB
PCB ASSEMBLY
1400 PCB-N0920C-PSW PCB ASSY POWER LED
WAFERS
J25 2102-021R-004 WAFER 2P P2.5 RIGHT
LED
LED1 3700-3538-B LED 3MM FLAT TOP BLUE
Parts marked with the symbol are critical with regard to the risk of fire and electric shock. Replace only with parts recommended by

EXPLODED VIEW
NA
D
SOFT
CLIPPING
PROTECTION
FiveChannelPowerAmplifierS250
2
1
3
4
5
6
7
8
9
10
12
13
14
15
16
17
18
19
20
21
22
23
24
27
26
25
28
30
29
11
30

EXPLODED VIEW PARTS LIST
Location Part Number Description Quantity
1 S100-2011-3 POWER BUTTON 1
2 S250-2002-1 FRONT PANEL 1
3 S250-2003-3 SUBFASCIA 1
4 S250-2014-3 LEFT SIDE PANEL 1
5 S250-2024-3 RIGHT SIDE PANEL 1
6*AH S250-2006-2 REAR PANEL 120V 1
6*C S250-2006-2 REAR PANEL 230V 1
7 S250-2057-1 REAR PANEL BAR B 1
8 S250-2047-1 REAR PANEL BAR A 1
9 S250-2027-4 HEATSINK B 1
10 S250-2017-4 HEATSINK A 4
11 S250-2037-2 HEATSINK BAR 1
12 S250-2005-2 TOP COVER 1
13 S250-2034-1 BASE PLATE 1
14 S100-2013-2 DIECAST FOOT 4
15 5600.0005 TIE-WRAP 4
16 1806-3520-0 STANDBY TRANSFORMER 1
17 4554.0052 POWER TRANSFORMER 1
18*C 1806-3519-0 EMI FILTER 20DBAG5 1
19 5200-3441-0 POWER SWITCH 1
20 2113-1206-0 RCA JACK 5
21 4208.001 SPEAKER TERMINAL BLACK 5
22 4208.0009 SPEAKER TERMINAL RED 5
23 2113-1144-0 AC INLET 1
24 4152-4621-0 LEVEL KNOB 5
25 PCB-N0920C-SW 12V TRIGGER PCB 1
26*AH PCB-N0920C-AMP POWER AMP PCB 120V 1
26*C PCB-N0921C-AMP POWER AMP PCB 230V 1
27*AH PCB-N0920C-PSU PSU PCB 120V 1
27*C PCB-N0921C-PSU PSU PCB 230V 1
28 PCB-N0920C-PSW POWER LED PCB 1
29 PCB-N0920C-LED PROTECT LED PCB 1
30 5180.0004 TRANSFORMER BOLT/NUT 1
Parts marked with the symbol are critical with regard to the risk of fire and electric shock.
Replace only with parts recommended by the manufacturer.

3333
3838
3737
3636
3939
3434
3232
3131
PACKING DIAGRAM
REF. NO. PART NUMBER DESCRIPTION QTY.
31 8700.0058 LEFT CUSHION 1
32 8700.0059 RIGHT CUSHION 1
33 8700.0057 WRAPPING SHEET 1
34 860129 INNER CARTON BOX 1
35 860135 OUTER CARTON BOX 1
36 8120.0189 WARRANTY CARD 1
38 8700.0056 GLOVES 1 PAIR
39*AH 4150.0009 POWER CORD 120V 1
39*C 4150.0011 POWER CORD 230V 1
37 8100.0174A OWNER’S MANUAL 1
NA
D
PROTECTIONCLIPPING
FiveChannelPowerAmplifierS250
!
!
3535

SERVICE MANUAL S250
FIVE CHANNEL
POWER AMPLIFIER
Copyright 2003
NAD Electronics International
633 Granite Court
Pickering, Ontario
Canada L1W 3K1
No portion of this publication may be reproduced without the written permission of NAD Electronics
International. Many of the circuits and software programs described within are covered by patents
and other international property laws and are used with express permission or license agreements
from the owners.
Printed in Canada