NAD
SER
VICE
MANUAL
C 420
STEREO
AM/FM TUNER
C
420
STEREO AM/FM
TUNER
2
SERVICE SAFETY PRECAUTIONS
1.
Safety check out
(Only U.S.A. model)
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.
CONTENTS
DESCRIPTION
PAGE
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
REAR PANEL / FRONT PANEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
DISASSEMBLY INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
ADJUSTMENT POINTS DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
INSTRUMENT SETUP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
ALIGNMENT PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
PCB LAYOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-12
SCHEMATIC DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-16
IC BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17-19
ELECTRICAL PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20-25
EXPLODED VIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
EXPLODED VIEW PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
PACKING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
3
SPECIFICATIONS
AM TUNER SECTION
Input level is expressed as the reading in open-circuit
of 75-ohm source impedance signal generator
Usable Sensitivity (999/1000kHz)
30dBµ
S/N Ratio (5mV in)
38dB
THD (5mV in)
3%
IF Rejection (450kHz)
36dB
Image Rejection (F+2xIF)
28dB
Selectivity
17dB
Output
130 +/-20mV
Loop Sensitivity (20dB S/N)
999/1000 kHz
66 dB
603/600 kHz
66 dB
1404/1400 kHz
66 dB
Frequency response (100 - 2.3 kHz, 5mV)
±6 dB
FM TUNER SECTION
*C
*AH
Input level is expressed as the reading in open-circuit
of 75-ohm source impedance signal generator
Usable Sensitivity (98 MHz)
13 dBµ
13 dBµ
Signal / Noise Ratio
Mono
72 dB
72 dB
(60 dBµ, IHF wtd)
Stereo
66 dB
66 dB
Frequency Response (20 Hz - 15 kHz, 60 dBµ)
0±1.0 dB
0±1.0 dB
Channel Separation (60 dBµ)
30 Hz
33 dB
33 dB
1 kHz
42 dB
42 dB
10 kHz
32 dB
32 dB
Alternate Channel Sensitivity
(40 dBµ, ±400 kHz)
60 dB
45 dB
Capture Ratio (40 dBµ)
3 dB
3 dB
AM Suppression
(60 dBµ, 100% Mod.FM, 30% Mod AM)
65 dB
65 dB
Image Rejection (119.4 MHz)
85 dB
85 dB
I.F. Rejection (10.7 MHz)
78 dB
78 dB
Pilot Suppression (60 dBµ)
60 dB
60 dB
THD (60 dBµ, L=R 75 kHz for AH, 40 kHz Dev for C)
Mono
0.25%
0.25%
Stereo
0.35%
0.35%
Auto-Search sensitivity
On
24 dBµ
24 dBµ
Off
15 dBµ
15 dBµ
RDS Decode Sensitivity
26 dBµ
26 dBµ
PHYSICAL SPECIFICATIONS
Dimensions (Width x Height x Depth)
435 x 80 x 285 mm
Net weight
4 kg (8.8 lbs)
Shipping weight
5.1 kg (11.22 lbs)
4
REAR PANEL / FRONT PANEL
REAR PANEL
FRONT PANEL
1. FM ANTENNA
2. AM ANTENNA
3. OUTPUT
4. NAD-LINK IN/OUT
5. 12V TRIGGER IN
6. AC LINE CORD
1. POWER ON / OFF
2. STAND-BY LED
3. BLEND
4. MEMORY
5. FM MUTE / MODE
6. AM / FM
7. DISPLAY
8. PRESET / TUNE
9. DISPLAY AREA
10. PRESET / TUNE
AND
IMPORTANT NOTES
1. Show the software version
Press "PRESET/TUNE" and "TUNE UP" (
).
2. Light UP all the icon on the VFL
Press "PRESET/TUNE" and "TUNE DOWN" (
).
3. CPU Resets
Press "PRESET/TUNE" and "TUNE DOWN" (
) and any one key.
4. AM Step 10K/9K Change
Add D206: 10KHz / Delete D206: 9KHz.
5
4
3
1
2
7
6
6
DISASSEMBLY INSTRUCTIONS
1. Remove machine screws M 4.0 x 6.0 ( 1 to 4 ) from the side panels.
Remove tapping screw 3.0 x 8.5 5 from the back panel.
Refer to Figure No.1.
Figure No.1
2. Pull both sides of the TOP COVER slightly outwards 6 and tilt approx. 35° and then remove
in the direction as indicated by the arrow 7 . Refer to Figure No.2.
Figure No.2.
5