NAD 7130 User manual

NAD SERVICE
MANUAL
AM/FM RECEIVER

CONTENTS
REAR PANEL CONNECTIONS PAGE 3
SPECIFICATIONS PAGE 4
ALIGNMENT NETHOD PAGE 5-9
TUNER ADJUSTMENT POINTS PAGE 10
AMPLIFIER PCB LAYOUT AND WIRING DIAGRAM PAGE 11-12
SCHEMATIC DIAGRAM (NAD 7130 AMPLIFIER) PAGE 13-14
TUNER PCB LAYOUT AND WIRING DIAGRAM. PAGE 15-16
SCHEMATIC DIAGRAM (NAD 7130 TUNER) PAGE 17-18
AMPLIFIER, TUNER. DISPLAY PCB COMPONENT LOCATION PAGE 19-20
7130 PARTS LIST PAGE 21-28
EXPLODED VIEW PAGE 29
PACKING DIAGRAM PAGE 30
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REAR PANEL
1. AC Line Cord.
2. AC Outlets.
3. Speakers A.
4. Speakers B.
5. Antenna Terminals.
6. AM Rod Antenna.
7. Phono Ground.
8. Phono Input.
9. MM/MC Selector.
10.
CD Input.
11. Video Input.
12. Tape Rec/Play.
13. Preamp Out, Main In.
14. Soft Clipping.
15. Speaker Impedance.
FRONT PANEL
1. Power.
2. Phones.
3. Speaker Selector.
4. Bass.
5. Treble.
6. Bass EQ.
7. Infrasonic Filter Defeat.
8. Mono.
9. Dyn Sep Defeat.
10. Tape Monitor.
11. Input Selector.
12. Low Level.
13. Loudness Compensation.
14. Volume/Balance.
15. Tuning Display.
16. Status Indicators.
17. Tuning Pre-sets.
18. Memory Enter.
19. AM/FM.
20. Up/Down Tuning.
21. Search Mode (FM only).
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Specifications, NAD 7130 Stereo Receiver
Note: Measurements references to 8ohms are taken with the Speaker
Impedance selector set to “Sn (High)/' Measurements for 4and 2
ohms are taken with the impedance selector at "4n (Normal)."
Specifications are measured in accordance with EIA Standard RS-490
(IF A-202) for amplifiers and ANSI-IEEE Standard 185 (1975) (IHF
T-200) for tuners. Tuner sensitivity is measured via 75-ohm coaxial
input and converted to equivalent 300-ohm values.
Power Amplifier Section, Stereo Mode
CONTINUOUS AVERAGE POWER OUT- 30W
PUT INTO 8OHMS (min. RMS power
per channel into 8ohms, 20Hz—20kHz.
both channels driven, with no more
than the rated distortion)
Rated distortion (THD), 20Hz—20kHz 0.03%
Clipping power 8ohms 45 W
(max. continuous power 4ohms 48 W
per channel)
IF dynamic headroom at 8ohms +3 dB
IFH dynamic power 8ohms 60 W
(max. short-term power 4ohms 65 W
per channel) 2ohms 85 W
Slew factor >50
Slew rate 15 V/usec
Damping factor (ref. at 50Hz) >50
Input Impedance 22 KJZ
Input sensitivity for TW/40W out .1 5/. 84 V
Power amp gain 25 dB
THD (Total Harmonic Distortion, 20Hz- <0.03%
20kHz, from 250mWto rated output)
SMPTE I.M. (Intermodulation Distortion, <0.03%
60Hz 1.7kHz, 4:1, from 250mW to rated
output)
IHF I.M. (CCIF IM Distortion, (9-f-20kHz <0.03%
at rated output)
Bridged (Monophonic) Mode
CONTINUOUS AVERAGE POWER OUT-
PUT INTO 8OHMS (min. RMS power
into 8ohms. 20Hz—-20kHz, with no
more than the rated distortion)
IHF Dynamic Headroom at 8ohms
Dynamic power (max. short-term output,
8ohms)
Preamplifier Section,
Phono Input
Input Impedance (MM or MC) R=47Kn, C=100pF
Input sensitivity (1 kHz) MM: 0,45mV for IW out
2.5mVfor30W out
MC: 0.04mVfor IW out
0.25mV for30Wout
Input overload at MM: 18mV/170mV/1.5V
20Hz/1kHz/20kHz
THD (20Hz—20kHz) and IM Dist.
MC: 1.8mV/18mV/170mV
at +30 dB level 0.04%
Rl AA response accuracy 0,5 dB
S/N ratio, IHF A-weighted, MM: 76 dB re 5mV
with cartridge connected MC: 76 dB re 0.5mV
Line Level Inputs (Aux, Tape)
Input Impedance R=15Kn; C=100pF
Input sensitivity 26 mV for IW out
145mVfor 30W out
Maximum input signal >10V
Signal to noise ratio, A-weighted 85 dB re IW
100 dB re 30W
Frequency response, 20Hz—20kHz
Outputs
±0.5 dB
Preamp output Impedance 800 ohms
Maximum output level 8V
Tape output impedance 1000 ohms
Tape output infrasonic fillter 3dB at 13 Hz.
12dB/octave
Controls
Treble
Bess
Speaker Equalization
Infrasonic filter (switchable)
Audio muting (low level)
FM Tuner Section
Input Sensitivity Mono, -30 dB THD +N
Mono, 50 dB S/N
^Stereo, 50 dB S/N
Stereo, 60 dB S/N
Capture ratio at 25, 45 and 65 dBf
AM rejection
Selectivity Alternate channel
Adjecent channel
Image rejection
R.F. Intermodulation
I.F. rejection
SCA rejection
Subcarrier suppression (19+38 kHz)
THD at 100% modulation Mono
Stereo
Signal-to-noise ratio Mono
A-weighted, 65 dBf Stereo
Frequency response.
30-15 kHz
Stereo separation 1kHz
(Dyn Sep off) 30Hz-10kHz
AM Tuner Section
Usable sensitivity
Selectivity
Image rejection
I.F. rejection
Physical Specifications
Dimensions (width xheight xdepth)
Net Weight
Shipping weight
Power consumption
±7dBat lOKHz
±7dBat 100 Hz
+3 dB at 60 Hz
+6dBat 30 Hz
-3 dB at 15 Hz
12 dB/octave
-20 dB
10.3 dBf (1.8/iV/300a)
14.2 dBf (2.8 mV)
34.2 dBf (28 AV)
44.3 dBf (90 juV)
<1.5 dB
>62 dB
70 dB
6dB
75 dB
65 dB
75 dB
70 dB
60 dB
1KHz 100Hz-6KHz
0.09% 0.2%
0.09% 0.3%
82 dB
75 dB
(typ. 80 dB at 75 dBf)
±0.5 dB
50 dB
40 dB
300 mV
/
meter
35 dB
50 dB
50 dB
42 X10.8 X38 cm.
16.5 X4.25x 15 in.
8Kg/17 1b, 9oz.
9.4 Kg/20 lb, 13 oz.
50/60 Hz at 110, 120.
220 or 240VAC
150 W

ALIGNMENT METHOD
AUDIO SECTION 7130
IMPORTANT
Speaker Impedance switch should be in 8ohm position while adjusting center voltage and idling current.
INITIAL ADJUSTMENT (No load connected)
A. CENTER VOLTAGE
1. Connect DC millivoltmeter to Lchannel output terminals.
2. Turn on and adjust to 0V±30mV with VR401 (1KB). Connect DC millivoltmeter to Rchannel output
terminals and adjust VR402 to 0V±30mV.
B. IDLING CURRENT
1. Remove solder short across R461 and R462.
2. Connect DC millivoltmeter across R461 (112) (output transistor's collector resistor) and adjust RX1 for
26'30mV reading on meter.
Repeat adjustment with RX2, connecting meter across R462 (1^2).
3. Leave power on for minimum 5minutes.
FINAL ADJUSTMENT
C. CENTER VOLTAGE
1.Repeat step Aabove.
D. IDLING CURRENT
1. Repeat step Band adjust with RX1, RX2 for 30mVreading on meter.
2. After the alignment is finished, lO resistor R461, 462 is shorted by solder short.
AMPLIFIER ADJUSTMENT POINTS

FM ALIGNMENTS
NECESSARY INSTRUMENTATION
FM GENERATOR (less than 0.05% THD)
STEREO GENERATOR {less than 0.05% THD, more than 50 dB separation at 1kHz.
AUDIO GENERATOR (not necessary if FM generator has built in sweep; i.e. SOUND TECHNOLOGY ST 1000A and
ST 1020A)
2AC VTVM's (or one with left/right channel switch)
THD ANALYZER (resolution better than 0.1%)
OSCILLOSCOPE (5mV or better sensitivity, Xinput capability)
FREQUENCY COUNTER
VOM or DMM (high impedance, must read in mV)
DIODE DETECTOR PROBE
COPPER /FERRITE INDUCTOR
IMPORTANT While ail FM generator output levels hereafter are referred to the 300 ohm input, 75 ohm input can
be used, but be aware of possible equipment groundloops and divide the RF output level by 2.
Before alignments commence set input selector to tuner and release tape, mono and dynsep defeat
switches (out)
ALIGNMENT OF FRONTEND should only be necessary after repair to frontend or crystal oscillator
circuits (pin 2and 3on 1C7)
ATUNING VOLTAGE (OSCILLATOR)
It is essential to check tuning voltage before aligning the rest of the frontend.
1. Connect DMM between shield and pin 6on frontend.
2. Tune to 108 MHz and adjust L707 if voltage Is incorrect.
SPECIFICATION 20.5V ±0.5V
3. Tune to 87.5 MHz and read voltage, repeat step 2and 3if incorrect.
SPECIFICATION 3V ±0.5V
B. READJUSTMENT (TRACKING)
1. Connect RF generator to antenna input and detectorprobe to pin 1,IC2 (IF DETECTOR).
with ground to detectorshield. Adjust sensitivity of oscilloscope to maximum (5mV or better) and modulate
FM generator sweep ±300 kHz or more WITH modulating (sweep) signal connected to X-imput of
oscilloscope.
2. Set tuner to 90 MHz, enter into preset 1, and tune generator so that curve appears on oscilloscope. Turn
down RF Input level so that curve covers approximately 1/2 of oscilloscope display.
3. Check alignments of L702 -L704 -L705 by inserting copper/ferrite Inductor close to them while walching
curve on oscilloscope. Curve should decrease in height with either ferrite (same as Increasing Inductance, i.e.
more core) or with copper (same as decreasing inductance, i.e. extend size of coil). If curve increases ii size
more than 10%, adjust only the coil which reacts incorrectly. Adjust coils by gently extend or contract the
aircoil with anon-metallic and non-static tool (i.e. plastic knit-pin or awooden stick). Be careful rot to
deform coil.
4. Set tuner to 105MHz, enter into preset 2, and tune generator so that curve appears on oscilloscope.
5. Check L702 —L704 —L705 again with the ferrite/copper inductor. Curve should not increase mor^than
10% on any of the coils.
6. Repeat step 2+3+4+ 5if curve height is outside of telerances, if necessary distribute the error between 90
and 105 MHz. Check tuning voltage again if tolerances not possible to achieve.
C. IF ADJUSTMENT
1. Set tuner to approximately 98 MHz (the tuner must be tuned to an unoccupied frequency) enter into p-^set
3, and tune FM generator to display acurve on the oscilloscope.
2. Adjust L709 (IFT tuner frontend) to maximum and symmetrical curve on the display, using as little hput
signal as possible.
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detector coarse adjustment (OPTIONAL, NEEDED ONLY IF DETECTOR WAS REPAIRED).
1. Reduce sweep modulation level to +/- 75 kHz and set input level to 300 juV.
2. Adjust FM generator frequency so that both legs of the inverted U-shaped curve are equally high on the dis-
play. The curve should be almost perfectly symmetrical.
3Disconnect detectorprobe from tuner and oscilloscope. Connect either of the tape rec. outputs to the oscillo-
scope.
4.
Adjust IFT 1primary (closest to the rear of unit) to maximum curveheight and IFT 1secondary (closest to
the front of unit) to minimum curveheight and straightest possible line. Go back and forth between primary
and secondary till both are peaked,
NOTE: Both the cores should be within 1.5 mm from the top of the form.
DETECTOR ALIGNMENTS (FINAL)
1Disconnect detectorprobe and connect tape rec. outputs to VTVM's, oscilloscope and distortion analyzer.
2. Switch stereo generator to 1kHz 100% (+/- 75 kHz) mono modulation and oscilloscope to normal internal
sweep 0.2 mS and 0.5 V/cm sensitivity.
3. Detector reference frequency
Reduce FM generator output level while monitoring THD from left channel. When THD increases to 3%, fine
tune the FM generator frequency to minimum THD. Reduce FM generator output level and fine tune till no
reduction in the 3% THD can be achieved by fine tuning. Use this frequency for all the following detector,
MPX and DYN SEP adjustments.
NOTE: The typical input level for this 3% THD should be 1.6 /iV to 2.3 /iV. This is done only to “lineup"
the frequency from the generator to the tuner's frequency.
If IHF usable sensitivity (-30 dB THD+N =3.16% THD+ N) is to be verified, aproper IHF band-
passfilter must be used.
4. Connect DMM across TP 2(negative) and TP 1(positive). Set FM generator output level to 1000 /iV.
5. Adjust IFT 1primary (closest to the rear of unit) for 0Von DMM
TOLERANCE +/- 50 mV
6. Adjust IFT 1secondary (closest to the front of unit) for lowest THD
SPECIFICATION less than 0.1%.
7. Repeat steps 3-5 and 6till no further improvements. Record the DMM's final reading for use later in the
adjustment.
autosearch LEVEL
1. Connect DMM between 1C 2pin 12 and ground.
2Increase FM generator level upwards from 0and adjust VR 1so that DMM reading goes from 0Vto approxi-
mately 4.8 Vat 10 /iV.
TOLERANCE +/- 2juV
STEREO DECODER, MPX FILTERS.
1. vco
Connect afrequency counter between 1C 6pin 11 and ground.
2. Set FM generator to 1000 juV output and no modulation.
3. Adjust VR 3for a19000 Hz reading on the counter.
TOLERANCE +/- 100 Hz
4. Disconnect frequency counter and press DYN SEP defeat switch (in).
5. Stereo switch threshold.
Modulate FM generator 1kHz 45% left only plus 19kHz pilot 8-10 %.
6. Increase FM generator level upwards from 0and adjust VR 2so that stereo light turns on and audio outputs
as watched on VTVM and oscilloscope, switches to one channel only at 10 /zV input level.
TOLERANCE +5 juV
When turning input level down the unit will switch into mono at alower level, typically 5—7
NOTE:

7. Stereo separation
Set FMgenerator output to 1000 juV, modulate in mono only.
8. Adjust VR 4for identical outputs in the two channels.
TOLERANCE +/- 20 mV.
9. Modulate FM generator left channel only and adjust VR 5for minimum on right channel VTVM.
10. Modu late FM generator right channel only and adjust VR 5for minimum on left channel VTVM.
11. If the minimum in step 9 and 10 are different, adjust VR 5so that the readings are the same in both channels.
SPECIFICATION better than 40 dB separation.
12. MPX filter
Turn off audiomodulation, leaving pilot tone only. Disable IMF filter or external 19 kHz filter if used.
13. Adjust LPF 1left channel and LPF 2right channel for minimum output.
SPECIFICATION more than 60 dB suppression.
14. Release the DYN SEP DEFEAT switch (out),
DYIM SEP ADJUSTMENTS.
1.
Turn VR 6—VR 7and VR 8fully clockwise.
2DYN SEP separation effect.
Observe output from left channel with FM generator output level 1000 /iV and mdoulated 1kHz left channel
only.
Reduce audiomodulation only from stereo generator so that left channel output is reduced by 6dB (50%
stereo modulation).
The. 19 kHz pilot signal MUST REMAIN modulated 8-10%.
3. Set FM generator output to 50 /iV and adjust VR 7for -30 dB separation left to right channel.
TOLERANCE +/- 2dB
4. Switch modulation to right channel only while maintaining the same modulation level.
Adjust VRSfor —30dB separation right to left channel.
TOLERANCE +/- 2 dB.
5. DYN SEP auto defeat level.
Set generator output to 200 juV and adjust VR 6so that separation starts increasing when watching left
channel VTVM. Adjust FM generator output up and down around 200 iiW and make sure switching occurs
around 200 fJLV.
TOLERANCE +100 /-30 juV.
SYNTHESIZER FREQUENCY.
1. Tune to aknown accurate frequency source, i.e. broadcasting station or synthesized /digital display FM
generator, preferably in the midband (95 —100 MHz),
2. Connect DMM acrosTP2 (negative) and TP 1(positive).
3. Adjust VC 2so that DMM reads the same as recorded in E—7,
TOLERANCE +/- 10 mV.

AM ALIGNMENTS
Unless repairs have been done to Oscillator Section, do not not adjust AM OSC coil or Trimming Capacitor.
If OSC Adjustment is needed, connect high impedance voltmeter (preferably DMM) between R35 and ground.
A. OSC ADJUSTMENT
1. Tune unit to show 1610KHz or 1602KHz on display and adjust VC3 to read 7.5V on DMM.
2. Tune unit to show 520KHz or 522KHz on display and adjust L3 to reads 1V±0.5V on DMM.
3. Repeat step 1and 2until no further improvement.
BIF ADJUSTMENT
1. For IF adjustment and Tracking adjustment connect VTVM to loudspeaker output (or tape output), only
one channel connection needed, and connect signal generator to antenna terminals. Adjust generator for 30%
modulation and approx. lOOjuV input.
Tune both generator and receiver to approx. lOOOKHz, and adjust generator frequency for maximum reading
on VTVM. Then adjust IFT2, and IFT3for maximum reading on meter.
C. TRACKING ADJUSTMENT
1. Tune unit and generator to show approx. 600KHz and adjust L2 to maximum reading on VTVM.
2. Tune unit and generator to show approx. 1400KHz and adjust VC1 (Trimming Capacitor) for maximum
reading on VTVM.
3. Repeat step 1and 2until no further improvement.
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TUNER ADJUSTMENT POINTS
FRONT END
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