NAD 1700 User manual

SERVICE |
| NAO MANUAL
MONITOR SERIES
1700
PREAMPLIFIER/ TUNER —

NAD 1700 SERVICE MANUAL
NOTE: This manual covers all versions.
A: U.S.A.
A1: Canada
B: U.K.
B1: Australia
C: EUROPE and others
C1: W-Germany
Page Contents
3 Rear/Front View
4-6 Specifications
6 Safety Notice
7 Suggested Equipment Hookup
8-10 FM Alignment
11 AM Alignment
12 Preamp Adjustment
13-14 Wiring Diagram
15-16 Preamp PCB Layout
17-18 Preamp Schematic Diagram
19-20 Tuner PCB Layout
21-22 Tuner Schematic Diagram
23-28 Electrical Parts List
29-30 Exploded Parts List
31 Exploded View

REAR PANEL | CAUTION |
RISK OF ELECTRIC SHOCK
1. AC Line Cord. 9. Video Sound Input. DO NOT OPEN
2. AC Outlets (not in U.K. model). 10. CD Input. CAUTION: TO REDUCE
3. AM Antenna Terminals. 11. Tape 1 Input/Output. SHOCK DO NOT REMOVE
4. FM Antenna Input. 12. Tape 2 Input/Output. eee ee CABLE
5. AM Rod Antenna. 13. Output (Normal). Sea ee RIED
6. Phono Ground. 14. Output (High). SERVICE PERSONNEL
7. Phono Input. 15. EPL (External Processor) Input/Output.
8. MM/MC. 16. Infrasonic Filter On/Off.
==
im AM ANTENNA. J switcren
PHONO
:
TAPE
1
TAPE
2
OUTPUT
EPL
GROUND
ghhoNe
[VIDEO
CD
IN
OUT
IN
OUTNORMAL.HIGH
IN
OUT
|
J
swircrten
4
INFRA
©
wcnm
OFF
ON
I
swicueo
i
ii
qh
)
UNSWITCHED
J
6
7
8 $
10
11
12
3
14
15
16
1
2
FRONT
PANEL
1,
Power.
8.
Tone
Control
Bypass.
15.
Balance.
22.
AM/FM.
b
2.
Phones.
9.
Treble.
16. Volume.
23,
Mono.
3.
Phase
Invert.
10. Treble
Range.
17.
Tuning.
24.
Memory
Enter.
4.
EPL
(External
Processor
Loop).
11.
Tape
Copy.
18. Tuning
Display.
25.
Bank
Selector.
5.
Bass
EQ.
12.
Tape
Monitor
1 and
2. 19. Status
Indicators.
26.
Pre-sets.
6.
Bass
Range.
13.
Input
Selector.
20.
FM
NR Off.
7,
Bass.
14.
Low
Level.
21.
IF
Narrow.
1
26 25
24 23
22
21
20
19
18
17
el
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INVERT
NA
lonitor
Series
Preamp
Junet
170¢
:
TUNING
STEREO
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FM NR OFF — =
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SPECIFICATIONS
Tuner
specifications
are
measured
in
accordance
with
ANSI-IEEE
Standard
185
(1975),
i.e.
IHF
T-200.
FM
sensitivity
is
measured
via
75-ohm
coaxial
input
and
expressed
in
nominally
equivalent
300-ohm
values.
All
measurements
taken
in
Normal
|.F.
mode
except
where
specified.
Preamp
specifications
are
measured
in
accordance
with
EIA
Standard
RS-490
(formerly
IHF
A-202)
and
are
referenced
to
the
NORMAL
output.
Signal
levels
are
6.dB
higher
at
the
HIGH
output;
divide
input
sensitivity
values
by
2.
PREAMPLIFIER SECTION
PHONO INPUT
Input
Impedance
(MM
or
MC)
R
=
47K
ohms,
C = 120 pF
Input
Sensitivity
MM
1.4mV
(1
kHz,
0.5V
out)
MC
100
uV
Input
Overload
at
MM
20/180/1500
mV
20H2/1kHz/30kHz
Mc
1.5/13/110
mV
Signal/Noise
ratio,
IHF
A—
MM
76
dB
re5mvV
weighted,
with
cartridge
connected
MC
76
dB
re
0.5
mV
THD
(20
Hz—
20
kHz)
and
IM
<0,04%
Distortion at + 30 dB level
RIAA
response
accuracy
+0.5
dB
LINE LEVEL INPUTS (CD, VIDEO, TAPE, EPL)
Input
Impedance
R
=
100KQ,
C
=
220pF
input
Sensitivity
80
mV
for
0.5
V
out
Maximum
Input
Signal
10V
Signal/Noise
ratio,
A-weighted
>
100
dB
re
0.5
V
out
>110dBre2V
Frequency
Response
20Hz
—
20kHz
+0.3
dB
OUTPUTS
Output
Impedance
.
Tape
or
EPL
1000
ohms
Normal 600 ohms
Phones & High 150 ohms (will drive all
headphone impedances)
Maximum
Output
Level
12
V
(all
outputs)
Tape
Output
Infrasonic
Filter
—3
dB
at
14
Hz,
12
dB/octave

CONTROLS
Treble
Bass
Bass Equalization
Infrasonic Filter (switchable)
TUNER SECTION
FM SECTION
Input Sensitivity
Mono, —30 dB THD +N
Mono, 50dB S/N |
Stereo, 50 dB S/N
FM NR on:
FM NR off:
Stereo, 60 dB S/N
FM NRon:
FM NR off:
Capture Ratio
AM rejection
Selectivity
(Normal |.F.)
Selectivity
(Narrow IF.)
Image rejection
R.F. intermodulation
l.F. rejection
SCA rejection:
Subcarrier suppression:
THD at 100% modulation
Signal-to-noise ratio,
IHF weighted
Frequency response
Stereo separation
(FM NR off)
dBf
10.3 dBf
13 dBf
25 dBf
35 dBf
35 dBf
45 dBf
Mono:
Stereo:
Mono:
Stereo:
+12 dB at 3, 6, or 12 kHz
+12 dB at 50, 120, or 250 Hz
+3 dB at 60 Hz
+6 dB at 36 Hz
—3 dB at 14Hz, 12 dB/octave
uV/750hms — uV/300 ohms
0.9 uV . 1.8uv
1.2uV 2.4uV
5uV 10 uV
15uV 30 uV
15 uV 32 uV
50 uV 100 uV
<1.5dBfrom 45 to 85 dBf
>65 dB at 45 and 85 dBf
75 dB alternate channel
7 dB adjacent channel
85 dB alternate channel
20 dB adjacent channel
>90 dB
>65 dB
_ >100dB
'>70 dB
>60 dB (19 + 38 kHz)
1kHz 100Hz—6kHz
0.08% 0.2%
0.08% 0.3% .
>82 dB
78 dB at 65 dBf,
80 dB at 85 dBf -
30 Hz— 15 kHz +0.5 dB
50 dB at 1 kHz By
40 dB from 30 Hz to 10 kHz

AM SECTION
Usable sensitivity
Selectivity
Image rejection
|.F. rejection
S/N ratio
THD
PHYSICAL SPECIFICATIONS
Width x Height x Depth
Net Weight
Shipping Weight
Power Requirement
300 uV/meter
35 dB
50 dB
50 dB
45 dB (30% mod., 50 mV input)
0.5%
43.5 x 12 x 29.3 cm
(17.1 x 4.75 x 11.5 in.)
6.6 kg (14.5 Ibs)
7.6 kg (16.7 Ibs)
50/60 Hz at 110, 120.
220 or 240 VAC 30 W
NOTE : NAD reserves the right to change specifications or designs at any
time without notice. All specifications are those in effect at the time of
printing.
SERVICE SAFETY PRECAUTIONS (UL)
1. Use exact replacement parts for critical locations, marked “A” on parts list.
2. Return lead dress to original position, and re-install protective covers.
3. Before returning to customer, test for shock hazard; use either method A or B:
A. Leakage test, “cold”:
1. Unplug AC cord, turn power switch ON.
2. Connect one lead of High Voltage Insulation Tester to both prongs of AC plug.
3. Touch other lead to all exposed metal parts.
4. Impedance measurement must be 0.3 - 5.0 Megohms.
B. Leakage test, “live”: ;
1. Plug unit directly into AC outlet; do not use isolation transformer.
2. Connect one lead of Leakage Current Tester to earth ground.
3. Touch other lead to all exposed metal parts.
4. Leakage measurement must be less than 0.5 milliamps.

SUGGESTED INSTRUMENTATION HOOKUP — FM ALIGNMENT
WITH BUILT~IN SWEEP
1E: ST 1000A
SEEECE
FREQ. COUNTER
(IF NOT USING
SYNTHESIZED
FM GENERATOR)
DUMMY
ANTENNA
750
DISTORTION METER
ee
DISTORTION
OUTPUT
INPUT
SCHEMATIC DIAGRAM OF DETECTOR PROBE
C1 02
330p Diodes should be point-contact
FROM OUT germanium; Some commonly
TUNER Ico | TOSCOPE available types are: OA80
OA81
AA119
1N60
1N34
1N22
PICTORIAL DIAGRAM OF DETECTOR PROBE
R1 CENTER LEAD
TO PIN1 TO SCOPE
{C103
Keep jeads as shortas possible, to
TO TUNER GND. \. SHIELD minimize stray signal pickup.
AT FRONTEND

FM ALIGNMENTS
NECESSARY INSTRUMENTATION
e Stereo Modulator (less than 0.05% THD, more than 50dB Sep.)
@ FM Generator (less than 0.05% THD)
e 75 ohm Dummy Antenna (if needed by generator)
® Audio Oscillator (not necessary if FM Generator has built-in sweep, e.g., SOUND TECHNOLOGY ST 1000A or
ST 1020A)
@ 2 AC VTVM's (or one with a Left/Right switch)
@ THD Analyzer (resolution less than 0.1%)
® Oscilloscope (5mV or better sensitivity, X-Y capability)
e Frequency Counter
e Detector Probe
IMPORTANT NOTES
1) RF levels are at antenna input.
2) Before alignments commence, switch off IF NARROW, FM NR and MONO; select FM.
3) If FM Generator is not synthesizer-type, be sure to check its frequency with Frequency Counter when
adjusting detector and multiplex decoder circuits.
4) Hum in measurements may be caused by ground loop via antenna cable; if so, use isolation balun, or isolate
cable shield and hot with small capacitors (470~ 1000pf).
To adjust front-end coils, bend gently with wooden or plastic tool (non-interactive).
—
5
—
A. FM LOCAL OSCILLATOR FREQUENCY
1. Connect Frequency Counter between TP-107 and Ground.
2. Tune to 90 MHz (No RF input needed).
3. Adjust C-278 so that reading is 100.700MHz +/— 2kHz.
B. FRONT-END ALIGNMENTS (should only be necessary after repair to front end).
TUNING VOLTAGE
1. Connect DMM between TP-101 and Ground.
2. Tune to 88.00MHz, and adjust L-6 if reading is not 3.2V +/— 0.5V.
3. Tune to 108.00MHz, and check that reading is 22.5V +/— 1.5V.
4, Repeat above steps 2 and 3 until within tolerance.
TRACKING
1. Connect FM Generator to 75 ohm antenna input (modulate +/— 150kHz sweep) and Detector Probe to
Pin 1 of IC-103 (ground to tunershield).
2. Adjust vertical sensitivity of Oscilloscope to maximum, and set to X-Y mode. (X input is sweep signal,
Y is detector probe).
3. Set tuner to 105MHz, enter into Preset 2, and adjust generator so that curve appears on Oscilloscope, and
covers approximately 1/2 of display.
4. Adjust C-2, C-10 and C-12 for maximum curve height, while reducing FM Generator output, if necessary,
to keep entire curve on display.
. Set tuner to 9OMHz, enter into Preset 1, and adjust Generator so that curve appears on Oscilloscope.
. Adjust L-2, L-4 and L-5 for maximum curve height.
7. Repeat above steps 3, 4, 5 and 6 (use Preset 1 and 2) until both curves are at maximum height.
Note: 105MHz curve is typically slightly higher than 90MHz.
a
—
b
=
Oo ol
Cc. IF ADJUSTMENTS
1. Set tuner to approximately 98MHz (must be an unoccupied frequency), and adjust FM Generator to
display curve on the Oscilloscope.
2. Adjust L-8 and L-101 for maximum and symmetrical curve using as little RF input as possible.

. DETECTOR ALIGNMENT
. Remove Detector Probe, and connect the Tape, Output to Distortion Analyzer and Oscilloscope.
. Connect DMM between TP-103 (—) and TP-104 (4).
. Tune to 98MHz and feed 1000uV from FM Generator (Modulate 1kHz 100%, Mono).
. Adjust L-102 Secondary for lowest THD. Specification: less than 0.12%.
. Adjust L-102 Primary for OV reading on DMM. Tolerance: +/— 50mV.
. Repeat above steps 4 & 5 until no further improvement.
aoahands —
. STEREO DISTORTION & SEPARATION
. Tune to 98MHz and feed 1000uV from FM Generator. Modulate 1kHz, 100% left (or right) only.
. Adjust L-101 and L-8 just slightly so that distortion on left (or right) channel becomes minimum.
. Check stereo distortion, wide IF: Specification: less than 0.1%, L + R, L only, R only, L — R.
. Next, select IF NARROW, and check distortion: Specification: less than 0.15%, L only, R only, L— R.
. Set IF to wide and modulate L only. Adjust R-375 for minimum output on right channel.
Next, modulate R only and adjust R-375 for minimum output on left channel.
lf necessary, readjust R-375 so that readings become same on both channels. Specification: more than 46cB.
6. Select IF NARROW, and modulate left (or right) channel only. Adjust R-376 for minimum output on right
(or left) channel VTVM and Oscilloscope.
If necessary, readjust R-376 so that readings become same on both channels. Specification: more than 40aB.
ah WKND =
. AUTO SEARCH LEVEL
1. Set IF to wide. Connect DMM between TP-105 and Ground:”
2. Set FM Generator output to 10uV and adjust R- o78 so cent reading just goes from OV to 40V.
Tolerance: +/— 2pV.
. STEREO SWITCHING LEVEL
1. Set FM Generator output to 5uV, 1kHz 100% L + R.
2. Adjust R-379 so that the stereo
light just turns on. Tolerance: + 2uV.
Note: The tuner will switch into mono at a lower level, ‘ypically 4uV.
. SIGNAL METER LEVEL
1. Tune to 98MHz and feed 100uV from FM Getic ator
2. Adjust R-380 so that fifth LED just lights.
PARTIAL MUTING
1. Set FM Generator output to 0.5uV, 1kHz 30% Mono modulation. Set R-381 full CCW.
2. If S/N above 702760; set FM NR on, tune away from, then back to, RF Generator frequency.
3. Adjust R-381 so that muting just turns off.
. FM NR CIRCUIT: MULTIPLEX FILTERS
1. Check that FM NR is off.
. Set FM Generator output to 2000uV, 1kHz 100% L + R, and set reference for S/N measurement. Cancel the
stereo modulation and leave pilot tone.
. Adjust FL 102 (FL 103) for minimum subcarrier output on left (right) channel; Specification: less than — 60dcB:
. Adjust FM Generator output so that S/N ratio reads 50cB.
. Switch FM NR on, and adjust R-148 so the S/N is improved by 8dB.
. Switch FM NR off, and adjust FM Generator output so that S/N ratio reads 60cB.
. Switch FM NR on, and check that S/N is improved by approx. 2dB.
N
SN Oof W

10