Nad 7175 PE Service Manual

Page 1

SERVICE
MANUAL

7175PE

AM/FM RECEIVER

NAD 7175PE SERVICE MANUAL

NOTE: This manual covers a versions,
A: U.S.A.

A1: Canada

B: U.K.

B1: Australia

C: EU ROPE and others

C1 : W~Germany

TABLE OF CONTENTS PAGE
LOCATION MAP 2
SPECIFICATION 3 - 5
INTERNAL VIEW 6
SUGGESTED INSTRUMENTATION HOOKUP 7
FM ALIGNMENTS 8 - 11
AM ALIGNMENTS 12- 13
AMPLIFIER ALIGNMENTS 14
AMPLIFIER P.C.B. LAYOUT DIAGRAM 16-17
SCHEMATIC DIAGRAM (AMPLIFIER SECTION) 18-19
TUNER P.C.B. LAYOUT DIAGRAM 20-21
SCHEMATIC DIAGRAM (TUNER SECTION) 22-23
WIRING DIAGRAM 2425
EXPLODED VIEW PARTS LIST 26-28
EXPLODED VIEW 29
ELECTRICAL PARTS LIST 30-34

Page 2

REAR PANEL

1. AC [me cm
z ac Outlets (not in u K. version).
. Speakers A.

. Speakers 5.

. manna Terminals

. AM Rod Antenna.

: MM/MC Seledor
. Video Sound input.

(lamp om. Mam in
50 W?
t Smker luminance,

11 Human AnniEnE

L Cordon d'alimanlaiion

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a Encemles A

l Enwmes B

Barnes danlennes

Antenna AM.

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FRONT PANEL LE PANNEAU AVANT FHONTSEHE
Power 1. Alimentaimn 1. Neuschalter
Phones 2. Casqve deeaule 2. Kepmever-Ansenlun.
Speaker Seminar 3. Selemenr d enoeintes :1. umsnvsmervlvahlschalter
Bass 4. Graves. 4. BaGsIeller.
Treble. 5. Avgus. 5. Hehenslellev
5m EC. 8. Bass E0 6. Ball Equalizer-Schalter.
lnlmsonrc FIllerOfl, 7, F>l|ve mirasomque 1. Schalterlfiv lnlraschall-Film
no. a. Mono 8. Mono/Slereo-Schanet
FM NR 011. 9. FM NH eeleai. 9. Steveo-Rauschmmeemng
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Recording Input seieaor.
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, Loudness Compensahen. 1:. Common: 69 contour Sonora 1:. Gehomchllqsfl.avmarke-Einsteltum;
, Volume/Balance. 14. Volume/Equrlibrage 14. Lamslulks/Balanca»sleller.
. Tuning Display, 15. Michage de la llaquwws element 15. Ahsllrflmlnleige
. sums Indicators. 1s. remains, Is. Anzebgen rm Beinehszuslénde
. Stallon Pressure 17. Touches fie présélndlon 17. Slall'onsmslen
. Memory sum 1:. Memoirs. l8. Emgabebereuman 1m Slationslasienspeicher.
. AM! FM. 5. AM / FM 19. Wellenbsvelchischaltef 101 UKWJMItlelwelle.
. Up/Dawn Tuning 211. Synlo'llsauon eleclromaue 20. Wippe zur Frequenzemmllung.
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6 7 8 9 10 11 1213

SPECIFICATIONS

NOTE: Measurements referenced to 8 ohms are taken with the Speaker Impedance Selector set to 8 ohm (High)".
Measurements for 4 and 2 ohms are taken with the impedance selector at "4 ohm (Normal)". Specifications
are measured in accordance with EIA Standard RS490 (IHF A-202) for amplifiers and ANSHEEE 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

CONTINUOUS AVERAGE POWER OUTPUT INTO 8 OHMS
(min. RMS power per channel into 8 ohms, 20 Hz - 20 kHz,
both channels driven, with no more than the rated distortion)

Rated distortion (THD), 20 Hz ~ 20 kHz

Clipping power (max. continuous power per channel)

IHF dynamic headroom at 8 ohms

IHF dynamic power (max. short-term power per channel)

Peak output current (amperes)

Slew factor

Slew rate

Damping factor (ref. 8 SI, at 50 Hz)

Input impedance

input sensitivity for 1 W/rated power

Power amplifier gain

THD (Total Harmonic Distortion, 20 Hz - 20 kHz, from
250 mW to rated output)

{ SMPTE LM. (lntermodulation Distortion, 60 HZ + 7 kHz,

4:1 , from 250 mW to rated output)

lHF LM. (CClF lM Distortion, 19 + 20 kHz at rated
output)

8 ohms

8 ohms
4 ohms
2 ohms

75 W (18.7 dBW)

0.03 %
80 W
+6 dB

300 W
400 W
500 W

>4OA
>50

30 V/usec

> 50

30 k9.

120 mV/i V
28 dB (25X)
< 0.03 %

< 0.03 %

< 0.03 %

Page 5

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FM ALIGNMENTS

NECESSARY INSTRUMENTATION

FM GENERATOR (less than 0.05% THD)
STEREO GENERATOR (less than 0.05% THD, more than 50 dB sep.)
AUDIO GENERATOR (not necessary if FM generator has built in sweep; i.e., SOUND TECHNOLOGY ST 1000A and

ST 1020A)

AC VTVM's (or one with a left/right switch)-

THD ANALYZER (resolution less than 0.1%)

OSCILLOSCOPE (5mV or better sensitivity, X input capability)
FREQUENCY COUNTER

VOM or DMM (high impedance, must read in mV)

DETECTOR PROBE

IMPORTANT

FRONTEND

While all 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 levels
by 2.

Before alignments commence set input selector to tuner and release mono and FM NR OFF
switches (out).

Alignment of frontend should only be necessary after repair to frontend, or crystal oscillator
circuits (pin 2 and 3 on IC110). '

TUNING VOLTAGE (OSCI LLATORI

It is essential to check tuning voltage before aligning the rest of the frontend.
Connect DMM between ground and TP 102.
Tune to 108 MHz and adjust C 20 if voltage is incorrect.
SPECIFICATION 24.7Vi 0.5V
Tune to 88 MHz and read voltage. Adjust L 6 if voltage is incorrect.
SPECIFICATION 3.6V 1 0.5V
Repeat step 2 and 3 until readings are within tolerances.

RF ADJUSTMENT (TRACKING)

Connect RF generator to 300 ohm antenna input and detectorprobe to pin 1 IC 102 with ground to
tunershield. Adjust sensitivity of oscilloscope to maximum (5mV or better) and modulate FM generator
sweep i 300 kHz or more.

Set tuner to 105 MHz, enter into preset 5, and tune generator so that curve appears on oscilloscope.
Turn down RF input level so that curve covers approximately 1/2 of oscilloscope display.

Adjust C 3, C 9, C 11 and C 15 to maximum curve height while reducing RF input to keep entire curve
on display.

Set tuner to 90 MHz, enter into preset 1, and tune generator so that curve appears on oscilloscope display.
Adjust L l, L 2, L 3 and L 4 to maximum curve height.

Repeat steps 2, 3, 4 and 5 (use preset 1 and 5) until both frequencies are at maximum curve height.
NOTE: 105 MHZ curveheight is typically slightly stronger than 90 MHz.

IF ADJUSTMENT

Set tuner to approximately 98 MHz (the tuner must be tuned to an unoccupied frequency) enter into
preset 3, and tune FM generator to display a curve on oscilloscope.

Adjust L 5 and L 101 to maximum and symmetrical curve on the display, using as little input as
possible.

NOTE: Maximum input 500 uV, typical curveheight 4 rnV at 150 uV and i5 mV at 300 uV.