NAD 7220PE User manual

SERVICE
—
MANUAL

CONTENTS
-7220PE / 7020e
REAR / FRONT PANEL CONNECTIONS
SPECIFICATIONS
ALIGNMENT METHOD
PCB LAYOUT AND WIRING DIAGRAM, AMP , 7220PE / 7020e
PCB LAYOUT AND WIRING DIAGRAM, TUNER , 7220PE / 7020e
PCB LAYOUT, AMP , 7220PE
SCHEMATIC DIAGRAM, AMP , 7220PE
PCB LAYOUT, AMP , 7020e
SCHEMATIC DIAGRAM, AMP , 7020e
PCB LAYOUT, TUNER , 7220PE / 7020e
SCHEMATIC DIAGRAM, TUNER , 7220PE / 7020e
PARTS LIST, EXPLODED VIEW
EXPLODED VIEW
PACKING DIAGRAM
-- 2--
PAGE
PAGE
PAGE
PAGE
PAGE
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PAGE
PAGE
PAGE
11
13
15
17
19
21
23
25
27
31
32
20
22
24
26
30

EAR PANEL
AC Line Cord. 7. Phono Input.
AC Outlets. 8. Video Sound Input.
Speakers A. 9. CD Input.
Speakers B. 10. Tape Input/Output.
Antenna Terminals. 11. Soft Clipping.
Phono Ground. 12. Speaker tmpedance.
8 5 11 3 «12 4 2
BALIHIGH) 412 (NORMAL)
UNSWITCHED
250W MAX
antewa Liew Lewd
UNSWITCHED
250W MAX
“CAUTION
DO NOT OPEN
CAUTION TO REDUCE
THE RISK OF ELECTRIC
SHOCK, DO NOT REMOVE
COVER (OR BACK},
7
6
9
10
NO
SER-SERVICEABLE
1
PAATS INSIDE, REFER
SERVICING TO QUALIFIED
SERVICE PERSONNEL
ONT PANEL
Power. 7. Tape Monitor. 13. Center-tune indicator.
Phones. 8. Input Selector. 14, FM Stereo Indicator.
Extra Speakers. 9. Mono. 15. Tuning Pre-sets.
Bass. 10. Loudness 16. Memory Enter.
Treble. 11. Volume. 17. Search Mode.
Balance. 12. Tuning Display. 18. Up/Down Tuning.
12 13 14 15 17 18
FM STEREO.
CENTER TUNE
<P) >
VOLUME
(cara
TREBLE BALANCE
EXTRA
s SPEAKERS
O0e0 @MqQ WO (oom
[SS LA arma cS, Ae Le
TAPE
MONO LOUONESS.
WW
a

Specifications
NAD 7220PE Stereo Receiver
Note: Specifications are measured in accordance with EIA Standard RS-
490 (IHF A-202) for amplifiers and ANSI-IEEE Standard 185 (1975), i.e.
IHF T-200, for tuners. Amplifier measurements referred to 8 ohms are
taken with the Speaker Impedance selector set to 8Q (High).
Measurements for 4 and 2 ohms are taken’with Impedance
selector at 4Q (Normal).
Power Amplifier Section
CONTINUOUS AVERAGE POWER OUTPUT
AT 8 OHMS (minimum RMS
power per channel, both
channels driven, with no more
than the rated distortion) :
Rated distortion (THD), 20 Hz - 20 kHz
Clipping power, 1 kHz (maximum
continuous power per channel)
Dynamic Headroom at 8 ohms
Dynamic power (maximum 8 ohms
short-term power per channel) 4ohms
2 ohms
Slew factor
Slew rate
Damping factor (ref. 8 ohms, at 50 Hz)
T.H.D and SMPTE I.M. distortion from
250 mW to rated output
IHF |.M. (CCIF IM) and T.I.M. distortion
at rated output
Preamplifier Section.
Phono Input
Input Impedance
Input Sensitivity (1 kHz)
Signal-to-Noise Ratio with
cartridge connected, A-weighted
Input Overload at 20 H2z/1kHz/20kHz
RIAA Accuracy
High-Level Inputs (CD, Video, Tape)
Input impedance
Input Sensitivity
Signal-to-Noise ratio, A-weighted
Input Overload
Frequency Response
infrasonic Fitter
Controls
Treble
Bass
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
20 W (13 dBW)
0.04%
25 W
+4.4dB
55W
75W
85 W
> 50
15V/usec
> 30
< 0.04%
< 0.04%
R=47KQ , C= 100 pF
0.55 mV for 1 W out
2.4 mV for 20 W out
75 dB re 5 mV
20/200/1700 mV
+0.5 dB
R=40kQ ,C = 100 pF
33 mV for 1W out
150 mV for 20W out
84 dB re 1 Wout
97 dB re 20W out
>10V
20Hz - 20kHz +0.5, -1.0 dB
-3 dB at 15 Hz
24 dB/octave
+7 dB at 10kHz
+10 dB at 50 Hz
10.8 dBf (1.9 nV/3002 ,
or 0.95 pV into 75Q )
14.4 dBf (2.9 pn V/3002 )
37 Bf (40 pV)
47 dBf (120 pV)
Capture ratio (at 45 and 65 dBf)
AM rejection (at 65 and 85 dBf)
Selectivity
Image rejection
R.F. intermodulation
LF. rejection
SCA rejection
Subcarrier suppression (19 & 38 kHz)
THD at 100% modulation Mono, 1kHz |
100Hz-6kHz
Stereo, 1 kHz
100Hz-6kHz,
Signal-to-noise ratio Mono
‘ IHF weighted, 65 dBf Stereo
Frequency response, 30Hz-15 kHz
Stereo separation
AM Tuner Section
Usable sensitivity
THD
Selectivity
Image rejection
LF. rejection
SIN ratio (30% mod., 50 mV input)
Physical Specifications
Width x Depth x Height
Net Weight
ShippingWeight
Power Consumption
< 1.5 dB
> 60 dB
58 dB
70 dB
60 dB
90 dB
60 dB
60 dB
0.1%
0.2%
0.1%
0.3%
> 80 dB
> 74dB
+0.5 dB
45 dB
5yVv
0.5%
30 dB
45 dB
35 dB
45 dB
42 x 27.3 x 8cm.
6.5 x 103/4 x 334 in.
5.5kg (12.1 lbs)
6.8 kg (15 Ibs)
50/60 Hz at 110, 120,
220, or 240 VAC
150 W
Specifications are those in effect at the time of printing. NAD reserves the right to change
Specifications or designs at any time without notice.
Industrial Design: REINHOLD WEISS DESIGN/CHICAGO

ALIGNMENT METHOD
AUDIO SECTION 7220PE
IMPORTANT
Speaker Impedance switch should be in 8 ohm position while adjusting center volatge and idling current.
INITIAL ADJUSTMENT (No load connected)
A. CENTER VOLTAGE
1, Connect DC millivoltmeter to L channe) output terminals.
2. Turn on and adjust to 0 ¥ +- 30mV with VR411 (100 ohm). 7
Connect DC millivoltmeter to R channel output terminals and adjust VR412 to 0 V +- 30mv.
B. IDLING CURRENT
1. Remove solder short across R455 and R456.
2. Connect DC millvoltmeter across P403,P404 (output transistor's collector resistor) and adjust R443
for 26-30mY reading on meter.
Repeat adjust with R444, connecting meter across P405,P406.
3. Leave power on for minimum 5 minutes.
FINAL ADJUSTMENT
C. CENTER VOLTAGE
1. Repeat step A above.
D. IDLING CURRENT
1. Repeat step B and adjust with R443, Rd for 30mV reading on meter.
2. After the alignment is finished, 1 ohm resistor R455,R456 is shorted by solder short.
mo
CENTER VOLTAGE ADJ
RAa3
fOLING CURRENT Ao)
Mace
IDLING CURRENT ADJ
REZ
CENTER VOLTAGE AD}
AMPLIFIER ADJUSTMENT POINTS
-- 5 --

FM ALIGNMENTS
NECESSARY INSTRUMENTATION
FM GENERATOR (less than 0.05% THD)
STEREO
GENERATOR
(less
than
0.058%
THD,
more
than
50
dB
separation
at
1
KHz.
AUDIO
GENERATOR
(not
necessary
if
FM
generator
has
built
in
sweep;
i.e.
SOUND
TECHNOLOGY
ST
1000A
and
ST
1020A)
2
AC
VIVM's
(or
one
with
left/right
channel
switch)
THD ANALYZER (resolution better than 0.1%)
OSCILLOSCOPE
(5m
or
better
sensitivity,
X
input
capability)
FREQUENCY COUNTER
YOM or DMM (high impedance, must read in mV)
DIODE DETECTOR PROBE
COPPER/FERRITE INDUCTOR
IMPORTANT
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
level
by
2.
Before
alignments
commence
set
input
selector
to
tuner
and
release
tape,
mono
and
FM
NR.
defeat
switches
(out)
ALIGNMENT
OF
FRONTEND
should
only
be
necessary
after
repair
to
frontend
or
crystal
oscillator
circuits
(pin
2
and
3
on
Q911)
A. TUNING VOLTAGE (OSCILLATOR)
It
is
essential
to
check
tuning
voltage
before
aligning
the
rest
of
th
frontend,
1. Connect DMM between shield and pin 5 on frontend,
2.
Tune
to
108
MHz
and
adjust
L
101
if
voltage
is
incorrect.
SPECIFICATION 20.5V +- 0.5V
-3,.
Tune
to
87.5
MHz
and
read
voltage,
repeat
step
2
and
3
if
incorrect.
SPECIFICATION 3V +- 0.5¥
B. RF ADJUSTMENT (TRACKING)
1,
Connect
RF
generator
to
antenna
input
and
detectorprobe
to
pin
1,Q104
(IF
DETECTOR)
with
ground
to
detectorshield.
Adjust
sensitivity
of
oscilloscope
to
maximum
(SmV
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
appars
on
oscilloscope.
Turn
down
RF
input
level
so
that
curve
covers
approximately
1/2
of
oscilloscope
display.
J.
Check
alignments
of
L2-L
4-5
by
inserting
copper/ferrite
inductor
close
to
them
while
watching
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
in
size
more
than
10%
adjust
only
the
coil
which
reacts
incorrectly.
Adjust
coils
by
gently
extend
or
contract
the
aircoil
with
a
non-metallic
and
non-static
tool
(i.e.
plastic
knit-pin
or
a
wooden stick),
Be
careful
not
to
deform
coil,
4.
Set
tuner
to
105MHz,
enter
into
preset
2,
and
tune
generator
so
that
curve
appears
on
oscilloscope.
9.
Check
lL
2-14-45
again
with
the
ferrite/copper
inductor.
Curve
should
not
increase
more
than
10%
on
any of
the
coils.
6.
Repeat
step
2+3+4+5
if
curve
height
is
outside
of
telerances,
if
necessary
distribute
the
error
between
90
and
105
KHz,
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 preset 3, and
tune FM generator to display a curve on the oscilloscope.
2.
Adjust
11
(IFT
tuner
frontend)
to
maximum
and
symmetrical
curve
on
th
display,
using
as
little
input
signal
as
Possible,

D.
DETECTOR COARSE ADJUSTMENT (OPTIONAL,NEEDED ONLY IF DETECTOR WAS REPAIRED).
Reduce sweep modulation level to +/- 75 kHz and set input level to 300 uv.
Adjust FA generator frquency so that both legs of the inverted U-shaped curve are equally high on the display.
The curve should be almost perfectly symmetrical.
Disconnect detectorprobe from tuner and oscilloscope. Connect either of the tape rec. outputs to the
oscilloscope.
Adjust I 102 primary (closest to the rear of unit) to maximum curveheight and I 103 secondary (closest to the
front of unit) to minimum curveheight and straightest possibe 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)
Disconnect detectorprobe and connect tape rec. outputs to VTVM's, oscilloscope and distortion analyzer.
Switch stereo generator to 1 kHz 100X(+/- 75kHz) mono modulation and oscilloscope to normal internal sweep 0.2 mS
“and 0.5 V/cm sensitivity.
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 FM NR
adjustments.
NOTE: The typical input level for this 3% THD should be 1.6 uv to 2.3 uv. This is done only to “lineup” the
NOTE:
1,
2.
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, a proper IHF bandpassfilter must be used.
Connect DMM ACROSS P112 (negative) and P113 (positive). Set FM generator output level to 1000 wv.
Adjust I 102 primary (closest to the rear of unit) for 0 V on DMM.
TOLERANCE +/- 50 mV
Adjust I 103 secondary (closest to the front of unit) for lowest THD.
SPECIFICATION less than 0.1%.
Repeat steps 5 - 7 till no further improvements. Record the DMM’s final reading for use later in the
adjustment.
AUTOSEARCH LEVEL
Connect DMM between 117 and ground.
Increase FM generator level SET TO 10 uY and adjust R117 so that DMM reading goes from 8.5 V to approximately
0.554 at 10 uv.
TOLERANCE +/-0.15v
STEREO DECODER, MPX FILTERS.
{.
VCO
Connect a frequency counter between IC 6 pin 11 and ground.
Set FM generator to 1000 uv output and no modulation,
Adjust VR 3 for a 19000 Hz reading on the counter.
TOLERANCE +/- 100H2
Disconnect frquency counter and press FM NR. defeat switch (inj.
Stereo switch threshold.
Modulate FM generator 1 kHz 45% left only plus 19 KHZ PILOT 8 - tOX.
Increase FM generator level upwards from 0 and adjust VR 2 so that stereo light turns on and audio outputs
as watched on VTVM and oscilloscope, switches to one channel only at 10 uv input level.
TOLERANCE +5 uv
When turning input level down the unit will switch into mono at a lower level, typically 5 - 7 u¥.
-- 7 --

: “Stero separation
Set
FA
generator
output
to
1000
uv,
modulate
in
mono
only.
Adjust
VR
4
for
identical
outputs
in
the
two
channels,
TOLERANCE
+/-
20mV.
Modulate
FM
generator
left
channel
only
and
adjust
VR
§
for
minimum
on
right
channel
VTVM.
Modulate
FM
generator
right
channel
only
and
adjust
VR.5
for
minimum
on
left
channel
VTVM.
If
the
minimum
in
step
9
and
tO
are
different,
adjust
VR
5
so
that
the
readings
are
the
same
in
both
channels.
SPECIFICATION
better
than
40dB
separation
MPX
filter
Turn
off
audiomodulation,
leaving
pilot
tone
only.
Disable
IHF
filter
or
external
19
kHz
filter
if
used.
Adjust
LPF
1
left
channel
and
LPF
2
right
channel
for
minimum
output
SPECIFICATION
more
than
60
dB
suppression
-- 8 --

AM ALIGNMENTS
Unless repairs khave been done to Oscillator Section, do not adjust AM OSC coil or Trimming Capacitor. If OSC Adjustment
is needed, connect hight impedance voltmeter (preferably DMM) between P123 and ground.
A. OSC ADJUSTMENT
1. Tune unit to show 600KHz on display and adjust L102 to read 1.75V+-0.05V on DMM.
B. IF ADJUSTMENT
. For IF adjustment and Tracaking 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. !v0 uv input.
Tune both generator and receiver to approx. {1000KHz, and adjust generator frequency for maximum reading on VTVM.
Then adjust IFT2, and IFT3 for maximum reading on meter.
—
C. TRACKING ADJUSTMENT
{. Tune unit and generator to show approx. 600KHz and adjust L101 to maximum reading on VTVM.
2. Tune unit and generator to show approx. {400KHz and adjust C138 (Trimming Capacitor) for maximum reading on VTVM.
3, Repeat step 1 and 2 unit no fkurhter imprivement.
-- 9 --
TUNER ADJUSTMENT POINTS
AM TRACKING ADJ.
It IF AM_ TRACKING ADJ.
L2 RF1
L4 RF2
LS MIX AM_OSC_ADJ.
L8 OSC
FM
DET
PRIMARY
AM
_IF
ADJ.
FM DET SECONDARY
AM LED SENS. ADJ.
FM MPX FILTER ADJ. FM AUTO SEARCH
FM MPX FILTER ADJ.
STEREO SEPARATION
SYNTHESIZER FREQ.

For
versions
A,
Al. F
ions
B,
Bl,
C,-Cl.
AMPLIFIER
PCB
LAYOUT
AND
WIRING
DIAGRAM
an
oe
a
ee
meee
YEL
UNSWITCHED S
oo '
VIO
BROWN
P122
TO TUNER PCB P12)
P120
ttt |
P.T
ie (120v) RED
=
N
sJo
3a
sf
N
(120V) RED
PHONES 7 POWER SW
P126
weoncewee
te
ORG
:
SPEAKERS
PHONES
POWER
SW
OWER
TO
TUNER
PCB
A,
16
Siig
RED
a,