Yamaha CR-420 Owner's manual

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YAMAHA offers you thanks and congratulations on your choice of the
CR-420 Receiver.
Embodying novel and useful features, it combines
superb broadcast reception with the finest audio quality, and is currently
setting new standards for recewer performance in its class.
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1. All-in-One Excellence |
Accurately matched performance specifications,
functions, and controls, give overall performance
which fully measures up to Yamaha's high stan-
dards for separate tuners, pre- and power amps.
2. Noise-Distortion Clearance Range
The CR-420 offers an extremely wide range of
output powers for which both noise and distortion
are below the rated value, for the widest possible
dynamic range in actual use. This was the basic
design concept for the audio section.
3. Direct Assessment of Differential Gain
This sophisticated technique enables Yamaha to
combine high station-getting ability, razor-sharp
tuning, and ultra-low distortion in the tuner
section.
4. Outstanding Receiver Cost/Performance
Yamaha's high-efficiency design policy, based
upon extra-high level circuit technology, has allow-
ed us to build in superb performance in relation
to the CR-420's cost.
5. Durable, Easy-Action Selector Switches
The switches operated by the CR-420 Input
Selector and Rec Out Selector are specially de-
signed for smooth, positive action and years of
dependability.
6. Continuous Loudness Compensation
Whatever your normal maximum listening level,
this Yamaha ‘special’ enables full compensation
for the ears’ reduced sensitivity to bass and treble
frequencies at lower listening levels.
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Caution — Read This Before Operating
Your CR-420 ....... ..............
Broadcast Reception .............. A
Listening to Records . . ...............
LOUDNESS, FILTER,
and TONE Controls ...............
The Special REC OUT Selector Switch and
Tape Playback and Recording .........
Block Diagram .....................
CircuitDiagram ....................
Specifications
Trouble Shooting . ..................
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The CR-420 is a high performance AM/FM
stereo receiver, with excellent selectivity, sen-
sitivity, low distortion. This manual is required
reading If you are to get the best from its
special features and controls.
Do not drop or otherwise jar the CR-420,
which is a precision electronic instrument.
Do not place the CR-420 where it will be ex-
posed to direct sunlight, excessive heat (for in-
stance over a radiator), cold, moisture, or dust.
Do not use chemical solvents (such as benzene
or alcohol) to remove traces of dirt. Wipe only
with a soft, slightly damp cloth.
Do not attempt to carry out internal adjust-
ments or repairs. Leave these to your local
service representative.
Do not assume your CR-420 is faulty before
checking “Trouble Shooting” list provided on
pages 20-21.
Operate all switches and knobs in accordance
with the instructions. Avoid applying undue
force, which shouid never be necessary, and do
not attempt to use intermediate settings.
Note that a muting circuit keeps the CR-420
silent for several seconds after switching ON, to
prevent the pops and clicks that can occur.
Do not connect other audío equipment to the
spare AC outlet sockets on the rear panel if it
will require more power than the outlets are
rated to provide.
Before switching on your CR-420, check that
the voltage selector is set to your local supply
voltage. Voltages available are 110/120/130/
220/230/240V AC.
Keep this manual in a safe place for future re-
ference, and refer to it frequently until you are
perfectly familiar with all CR-420 controls and
functions. |
ON/OFF Switch
Turn this switch to ON to connect the main elec-
trical supply, but leave the power switch OFF
while familiarizing yourself with the various con-
trols, and while you are connecting other audio
equipment.
DRIES A/B Jacks
Two headphone jacks are provided under the
plastic cover. Plugging into the jacks does not cut-
off power output to the speakers, so it is necessary
to use the OFF positions of the SPEAKERS push-
buttons if you de not want the speakers to func-
tion.
O SPEAKERS
These push-buttons select either or both of two
pairs of stereo speakers (or neither, for headphone
listening).
6
SH FILTER Switch
The HIGH filter has a 6 dB/octave cut-off slope
at frequencies above 10 kHz.
This determines whether AM (medium waveband)
or FM stations will be received.
© MODE Switeh
This gives the choice of stereo or monaural repro-
duction. Note that in the MONO position the am-
plifier section will reproduce all sources (including
FM stereo programs, etc.) monaurally. However,
even in the STEREO mode, FM stereo programs
will be reproduced monaurally if the MUTING
switch is OFF.
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With this switch in. the ON position, the muting
system will cut out (suppress) weak stations and
background noise interference and will ensure
continued optimum reception of FM stations. In
the OFF position, only monaural FM reception
will be possible. The FM MUTING functions by
ensuring that both inter-station noise and weak
signal strength stations will be muted at input
signal levels below 5 uV. In the OFF position,
even the weakest stations will be heard, but only
in the monaural mode.
NT
Control
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This large tuning knob gives smooth and positive
station selection, with the precision flywheel
mechanism preventing backlash. Also, the tuning
circuits utilize a wide air-gap high precision three-
gang variable capacitor, providing great sensitivity
and high stability.
O The IN
OLUME and BALANCE Controle
Use the VOLUME contro! to adjust the speaker
output to give the volume of sound that you
require. Always start operation with the VOLUME
control turned fully to the left (counter-clockwise)
at the '0' position before turning it up to the
volume level you require.
The BALANCE knob controls the difference in
output volume between the L and R (left and
right) stereo channels. Set this control to the
center ‘5’ position, at which there is a click stop,
unless you need to correct for a lack of balance
between the audio output of the two channels,
or to correct for a listening position which is not
equidistant from the two speakers. The BALANCE
control reduces the volume from the left-hand
speaker when turned clockwise, and reduces that
from the right-hand speaker when turned counter-
clockwise.
Switch
This selector switch is used to select the program
source of your choice, whether it be PHONO,
TUNER, TAPE deck, or AUX (for use with 8-
track tape cartridge playback, etc.). The PHONO
switch position input circuit is designed to operate
with normal moving magnet (MM) type cartridges.
® The LOUI
Use of some moving coil (MC) type cartridges is
possible, but other low output moving coil car-
tridges may require use of a step-up transformer
or a head amplifier.
® REC OUT Selector
This selects which program source will be recorded,
just as the INPUT SELECTOR selects which pro-
gram source will be heard. With the CR-420, you
can listen to one program source while recording
any other (copy a friend's tape while listening to
FM, etc). This eliminates “dead'” time while you
are taping, permitting you to enjoy the use of your
CR-420.while recording.
INESS Control
This boosts the extreme low and high frequencies
to compensate for our ears’ reduced sensitivity to
these frequencies at low volumes. Set it to the
FLAT position while the VOLUME control is set
to your highest normal listening level. Turning the
control counter-clockwise will reduce the volume
but will retain the natural balance between low
and high frequencies.
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SLE Controls
The bass and treble controls have a low turnover
frequency of 350 Hz and a high turnover fre-
quency of 3.5kHz respectively.
TUNING/AM SIGNAL METER
This meter fulfills two functions. When the
TUNER switch is set to FM, it functions as an
FM tuning meter, and when the switch is set
to AM, as an AM signal meter.
O FEM/AM Tuning Scale
The upper scale gives FM station frequencies in
MHz and the lower scale gives AM frequencies in
kHz. On the left-hand side of the front panel, the
upper LED lights to indicate FM operation and the
lower LED lights to show AM operation.
O LED Indicators
The top light-emitting diode is the FM indicator,
the bottom one is the AM indicator. When the
POWER switch is on, one of these two will
light up, depending on the setting of the TUNER
switch.
The center LED lights when a stereo broadcast
is received.
O Antenna Connections
Detailed instructions on AM and FM reception are
given on pages 10 to 11, but a quick check of
CR-420 functions can be carried out by connect-
ing the T-type internal (indoor) antenna provided
with the CR-420 to the terminals marked 300 £2
BAL. Attach the two arms of the ‘T,” fully ex-
tended, to the ceiling or walls of your room after
finding the best orientation. Note that such a
quick check can be carried out with the selector
switches vertical and all push-button switches in
the out (non-depressed) positions, except for the
SPEAKERS selector buttons {when you wish to
hear the output on your speakers rather than
using headphones).
@ TAPE PB and REG O
These are the terminals which are selected by the
INPUT SELECTOR switch on the front panel.
They include PHONO and AUX connections. The
AUX terminals can be used to connect an external
tuner, or for 8-track cartridge tape playback, etc.
Terminals
A tape deck can be attached to these input and
output terminals. Any source connected to the
CR-420 can be recorded on this deck, by setting
the REC QUT selector switch on the front panel
to the appropriate position. |
Recording can proceed while. any other source
selected by the INPUT SELECTOR is being
auditioned.
O GND (Ground) Terminal
This ground terminal is provided for the grounding
of turntable units, etc. Please make sure that all
such units are firmly grounded: failure to connect
the ground leads can result in unpleasant hum.
IS Terminals
The CR-420 can handle two sets of speakers {A or
B), with selection of either, both, or neither, by
use of the SPEAKERS push-buttons on the front
panel. Speakers should have impedances between
4 and 16 ohms, but with two speaker sets being
used at the same time, connect only speakers
with impedances between 8 ohms and 16 ohms.
Use speakers rated to take the full 22 Watts of out-
put power, or set the VOLUME control so that the
rated maximum speaker input power is not ex-
ceeded. Volume level should be reduced im-
mediately if there is increased distortion or a sense
of strain which indicates that the speakers are
being overloaded.
Making the Speaker Connections
1. Strip the insulation from the speaker cable for
1/2” (10 mm), and twist stray ends together. If
possible, solder the ends. Push the lever beneath
the terminal as shown in the diagram, and align
the inner and outer terminal holes. Then insert
the wire fully home. Release the lever, and the
wire end will be firmly clamped.
2. Use the upper (A) terminals first. Be careful
that the terminals identified by the + and —
signs above them are connected with the cor-
responding + and — terminals on the speakers.
A mistake will result in poor bass response and
ill-defined stereo image. Also be sure to con-
nect the left-hand speaker to the L speaker ter-
minals, and the right-hand to the R terminals.
3. Repeat this with the B terminals if other
speakers are to be connected. In all cases make
sure that connections are fully and firmly
made, or you may not be able to get any sound
from one or more speakers.
These spare AC OUTLETS are provided for your
convenience in connecting other items of audio
equipment. Only the top outlet is controlled by
the CR-420 POWER switch. This has a maximum
power rating of 200 Watts, and should used be
for items such as turntable units. Do not connect
any item which draws more than 200 Watts.
The lower outlet are not affected by the CR-420
POWER switch, and any items connected to them
must be switched on and off with their own
switches in the normal way. Note that the total
power available is only 200 Watts. Use them for,
say, your tape deck or decks.
LT AGE SELECTOR
The voltage selector must be set to your local AC
mains supply voltage. If the precise voltage is not
available, use the voltage immediately above.
Using an incorrect voltage setting will mean either
inferior performance or severe damage to your
CR-420.
© AC Electrical Power Line
Plug the CR-420 power cord into a main power
supply wall outlet socket, and make sure the line
is not likely to be tripped over.
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10
The T-type antenna provided with your CR-420
is adequate only in high signal strength areas and
under favorable conditions. In other cases, an ex-
ternal multi-element FM antenna is needed. If you
cannot obtain satisfactory reception with the T-
type antenna, this is an indication that you need
an external FM antenna.
The external antenna should preferably be located
fairly close to the CR-420, and mounted as high as
conveniently possible. Try various antenna orien-
tations, either pointing towards the weakest
station you intend to receive or away from the
major source of interference (preferably both,
although some compromise is usually necessary
in most locations).
If the antenna is intended for use with shielded
coaxial cable (which reduces losses and inter-
ference) use the 75 £2 UNBAL terminals on the
rear panel of the CR-420, and connect the cable
as shown. if the coaxial cable has a coaxial plug
connection, you may simply plug this into the
socket provided. Antennas intended for use with
the 300 2 BAL terminals on the rear panel (which
use feeder wire similar to that of the internal
antenna provided) can also be used with coaxial
cable if a matching transformer is attached to the
antenna. The use of coaxial cable is advisable
where the antenna must be located some distance
from the CR-420, or where interference from
automobile ignition, etc., is troublesome.
. Strip the insulation from outside the braided
sheath, and bend back the metal braiding
outside the insulation. Expose the projecting
central core wire as shown. Be careful not to
cut through any strands.
. Slacken the two retaining screws as shown and
insert the coaxial cable.
. Re-tighten the screws so that the clip grips the
exposed braided sheath.
. Connect the central core wire to the 75 © ter-
minal.
. Ensure that the braiding does not come into
contact with the inner core.
=
. Set the INPUT SELECTOR to TUNER.
2. Set the TUNER push-button to FM.
. Check that the FM indicator LED lights at the
right -hand side of the dial.
. All switches and knobs should be as shown in
the front-panel diagram (with all push-buttons
OUT except for the use of the SPEAKERS se-
lection buttons if you wish to use speaker
output rather than headphones).
. Set the Tuning Indicator to the frequency
(MHz) of the station you want to listen to.
Precise tuning is accomplished by watching
the FM tuning meter, and centering the needle
exactly in the middle.
6. Now tune to bring the FM TUNING meter
pointer to the exact center. This is the opti-
mum tuning position: set it carefully.
7. Check that the FM STEREO indicating LED on
the right-hand side of the dial lights if you in-
tend listening to a stereo rather than a monaural
broadcast.
This push-button switch should normally be left
in the ON (non-depressed) position.
In the recommended FM MUTING ON position,
the weakest stations will be cut out (muted), to-
gether with the inter-station noise. You will be
able to tune from station to station, free of back-
ground noise and remote, very poor quality
stations. This muting circuit is adjusted to elimi-
nate all signal inputs to the CR-420 which are
below a threshold value of 5 uV.
If a reduction in noise becomes desirable while
you are tuned to a specific FM stereo station, press
the FM MUT ING push-button to the OFF position.
The program will be heard with a marked improve-
ment in signal-to-noise ratio, but will revert to the
MONO mode. (Note: the stereo program will be
heard in the MONO mode although the MODE
push-button remains at the STEREO position.)
1. Set the TUNER
First set the TUNER FM/AM switch to AM, and
set the tuning indicator to the desired station fre-
quency. Adjust the tuning knob to give the maxi-
mum SIGNAL meter reading.
switch to AM (the AM
indicator on the right side of the dial scale
will light).
2. Set the Tuning Indicator to the frequency
(kHz) of the station you want to listen to.
Precise tuning is accomplished by watching
the AM signal meter, and tuning to give the
maximum reading.
Note: In the AM mode, the meter dial
functions differently than it does in
FM; it does not swing left or right
from the center.
3. The CR-420's AM bar antenna assures enough
sensitivity for clear reception of ordinary AM
broadcasting. In areas where reception is poor,
due to interference or distance from stations,
clear reception is possible by connecting an
external antenna and earth ground to the
AM ANT-GND terminal on the rear panel.
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12
The main AC supply plug of your turntable unit
may usually be conveniently inserted into the
spare AC outlet socket controlled by the CR-420
POWER switch. With some turntables it is impor-
tant not to disconnect the main supply without
first switching off at the turntable itself {read the
turntable instruction manual to check).
In this case you should use the unswitched
— spare AC outlet. The pin plugs on the output
lead from the turntable unit should be connected
to the PHONO terminal pin jacks at the left-hand
side of the back panel. Check that the L and R
pin plugs (for the left and right channels) have
been correctly inserted. Do not forget to connect
the turntable ground line to the GND terminal on
the CR-420 rear panel.
Switch on the receiver POWER switch, and set the
INPUT SELECTOR switch to PHONO. The
PHONO input circuit is intended for use with
standard moving magnet (MM), moving iron (MI)
or induced magnet (IM) type cartridges. Certain
moving coil (MC) cartridges can also be used, but
some have output levels too low for satisfactory
performance without the use of a step-up trans-
former or head amplifier. Note that the PHONO
input pin-plugs should never be connected or dis-
connected while the POWER switch is ON.
Always switch off your speakers by releasing the
SPEAKERS push-button when raising or lowering
the cartridge stylus over the record to prevent
overloading and possible damage. |
If you play monaural records, the signal-to-noise
ratio will be improved if you turn the MODE
selector to the MONO position.
If you notice a low-pitched rumble when playing
records, cut this out with the LOW filter. Simi-
larly you can use the HIGH filter to reduce un-
pleasant surface noise or record “scratch.” Use the
BASS and TREBLE, controls to give the best tonal
balance, and use the LOUDNESS volume control
rather than the main volume control to reduce
listening levels below your normal maximum,
Set this to the FLAT position (not the mid-point
5) when listening at normal high levels. The
LOUDNESS compensation curves shown enable
the same subjective tonal balance to be retained
as this control is turned down, unlike the
VOLUME control itself, for listening at lower
levels.
Response (dB)
Frequency (HI) 100 is 10
By setting the HIGH FILTER switch on, you
2
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6
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can cancel the frequencies over 10 kHz at 6 dB/ ; Hig
octave. This is useful for cutting tape hiss and so H Fire
noise from record scratches. The CR-420 also E UF
incorporates a Subsonic Filter which cancels the
extremely low frequency range below 15 Hz at ON
12 dB/octave, thus eliminating noises which may
be harmful to speakers.
Franucacy 11.4]
TREBLE
FLAT
The carefully chosen turnover frequencies of the
bass and treble tone controls have optimum influ-
ence at the higher and lower frequencies for major
correction of tonal character.
Response 1d 6)
Frequency 100Hz (EH 10EK
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Recording One Program Source While
Listening to Another
TUNER
HEC CUT SELECTOR INPUT SELECTOR
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14
Do not confuse the REC OUT SELECTOR and
INPUT SELECTOR switches. The INPUT SE-
LECTOR switch decides which program source
you hear. The REC OUT SELECTOR switch de-
cides which one you record. Yamaha receivers are
at present unique in offering independent choice
of audition and recording. Thus, for example,
you can listen to a record while tape recording
direct from the AM/FM tuner section.
The output leads provided with the tape deck are
used to connect the tape deck LINE output
terminals to the TAPE PB terminals on the rear
panel of the CR-420. Set the INPUT SELECTOR
to TAPE to play back tapes. Use the output level
controls on the tape deck or decks to adjust
the playback level so that there is no great change
in volume level when switching between TUNER
and TAPE terminals.
The tape-deck leads provided are used to connect
the deck LINE input terminals to the REC OUT
terminals. | |
Note that the INPUT SELECTOR switch setting
has no effect whatever upon the signal which will
be recorded via these REC OUT terminals. The
REC OUT terminals’ output signal is decided by
the REC OUT selector switch. If you refer to
the description of the REC QUT function on the
previous page you will see that the recording of
any of the program sources connected to the CR-
420 is possible: just set the REC OUT switch to
TUNER, PHONO, or AUX, as you wish.
Recording of any of these sources can proceed
while that source, or any other, is selected for
audition by the INPUT SELECTOR switch.
Monitoring of the recording while it is in progress
can also be carried out if you are using a three-
head deck designed for monitoring. Just set the
INPUT SELECTOR switch to the TAPE position
via which you are recording.
The level at which a tape recording is made is very
important: for full details of recording techniques
vou should consult the instruction manual pro-
vided with your tape deck. Adjustments in level
must be made with the input level controls on the
tape deck. Note that the signals from the REC
QUT terminals which are recorded by your tape
deck are not influenced at all by settings of the
tone, filter, and volume controls, etc., on the front
panel of the CR-420, and all such tonal and other
LTTE
adjustments must be made on playback. If you
record at too low a level you will notice a high
level of tape ‘hiss’ on playback, and if the level is
too high, the peak volume levels will be distorted
and you may even have difficulty in erasing them
later. |
For tape-to-tape dubbing, you will need two
decks. Connect tape deck LINE output, which
will be the program source, to the AUX terminals
of the rear panel of the CR-420, and recording-
tape deck LINE input to the REC OUT terminals.
Set the INPUT SELECTOR to the AUX position,
the REC OUT SELECTOR to the AUX position,
and you can complete tape-to-tape dubbing. If
there is a difference in the quality of the decks,
the best results will be often obtained if the
better deck is used for the recording rather than
for the playback. Check by making brief record-
ings in both directions and by comparing the
resulting quality of playback.
Check carefully that the L (left) and R (right)
channel pin-jacks have been correctly connected
before commencing to dub.
Recording of any of these sources can proceed
while that source, or any other, is selected for
audition by the INPUT SELECTOR switch. Mon-
itoring of the recording while it is in progress
can also be carried out if you are using a three-
head deck designed for monitoring. Just set the
INPUT SELECTOR switch to the TAPE position
via which you are recording.
The level at which a tape recording is made is
very important: for full details of recording tech-
niques you should consult the instruction manual
provided with your tape deck. Adjustments in
level must be made with the input level controls
on the tape deck. Note that the signals from the
REC OUT terminals which are recorded by your
tape deck are not influenced at all by settings
of the tone, filter, and volume controls, etc., on
the front panel of the CR-420, and all such tonal
and other adjustments must be made on playback.
If you record at too low a level you will notice
a high level of tape ‘hiss’ on playback, and if
the level is too high, the peak volume levels will
be distorted and you may even have difficulty
in erasing them later.
INPUT SELECTOR
TUNER
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Coil Mixer Compensation
REC OUT SELECTOR | PROTECTION |
ЕО Атр. AUX : Tone Amp. Power Amp.
—o | BALANCE | | VOLUME [TresLe | [HIGH FILTOR|[ LOUDNESS] ON
PHONO о
PHONO —o — 7—e 9 O7 SPEAKER A
OFF | OoFF
о
1
TUNER Stereo I
|
| ON
г © ave SPEAKER 8.
Mono $ O O orr $
| OFF ON
AUX SPEAKERS
AUX O ©
PHONO
C) |]
TUNER
—( © 7777
ТАРЕ { Y
TAPE PB (OH —0 ` v / Оу
To other ch, oA
REC OUT (Q
INPUT SELECTOR PHONES
oO
16
FM
NOTE)
ORESISTOR
TR201~204 | 2SC1917F
CAPACITOR
SwiQ1-1
103-111;
SLPi32B
TRIO1=:105,105,106,110,112 250 19186 orFerG
TR104,107--109,111125A894
ci . UPC
fo pest, TR401,402,411 ,412,417,418 : 260644 TR415,416 :28C1918 E orForG TUNING METER
A, 107.108 Tr A TR403 ~ 4086 .2SCIS71E orFarG TRA19,420: 25AB17 Cor Y , 2SAGS9 E or F
SS A TR407,408 1252659 TR421,422 : 25D476 AS, 2505250 or Ÿ
D105, 106 - TR409,410 TR423,424 | 2SBSEBAS, 2585950 or Y
2504580
TR413,414 -2SCIGZT OorY, ESCIT7SEorF D401-408: 151555
TR407
TR301, 302 ! 2801571 For G
TRR03,304 . 2SCIMIB For 6
DIAL POINTER LAMP
METER LIGHTING LAMP
TRS, 503 "2501918 EorForG
TREO ‚254044
TR504,505 125C1175EorF
TRSC6 : 250400
05017. 504, 509,513
"DSIZOY C, 151885
D505~508 :DSI5OAorB, 30D-1
5 :H7-33
0510 :HZ-
DST1,514 HZ-120
052 151555
GAGTÈO
UN SWITCHEC SWITCHED
GAGHSD
17
ANG
AUDIO SECTION
il
Minimum RMS Output Power per Channel
25 Watts (4 ohms) from 20 to 20,000 Hz at no more than 0.05% Total Harmonic Distortion
22 Watts (8 ohms) from 20 to 20,000 Hz at no more than 0.05% Total Harmonic Distortion
Continuous RMS power (802)
25 Watts (driven at 1 kHz)
22 Watts (driven at 10 ~ 40 kHz}
Distortion 20 Hz to 20 kHz
Input Sensitivity/Impedance
Phono to Rec Qut
0.05% 1.2V output
Aux, Tape to Sp Out (82)
0.02% at 11W
Phono
2 mV/1 kHz 50 k2
0.05% at 0.25 ~ 22W
Aux, Tape
120 mV/45 ka
Noise-Distartion Clearance Range {(NDCR) for 0.1% into 82 at 20 ~ 20 kHz
Maximum Input Level
From 100 mW to 22 Watts with Vol —20 dB (Phono Input to Sp Out)
Phono - -
110 mV at 1 kHz
Output Level/\mpedance
Rec Out terminals (Phono)
120 ;mV/2200 (rated) 9V (max. 1 kHz)
IM Distortion Aux Sp Out
0.02% at 11W/82
0.05% at 0.25 ~ 22W/8Q
Power Bandwidth (IHF)
10 Hz to 40 kHz
(Tuner)
6 k§2
Frequency Response
Damping factor {at 1 kHz)
Better than 40 into 852
Phono RIAA deviation
+0.5 dB
Aux, Tape 1, 2 to Sp Out
20 Hz to 20 kHz + 1,5 dB
FM SECTION
Tuning range
87.6 to 108 MHz
Usable Sensitivity (IHF MONO 84/98 MHz)
Tone Control Characteristics
3005
10.3 dBf/1,8 uV
7582
10.3 dBf/0.9 uv
Bass turnover frequency 350 Hz
Bass boost/cut +12 dB at 50 Hz
Treble turnover frequency 3.5 kHz
Quieting Characteristics (for 50 dB signal-to-noise)
Treble boost/cut
+11 dB at 20 kHz
Filters and Loudness Control Characteristics
Low (built-In)
10 Hz (12 dB/octave)
High
10 kHz (6 dB/octave)
Loudness control
Level-rated equalization
Signal-to-Noise Ratio (IHF-A Network)
Phono
91 dB for 10 mV, Shorted
Aux, Tape
97 dB
Mono 16.1 dBf (3.5 u V)
Stereo 38 dBf (43,5 uV)
Image Rejection (84/98 MHz) 50 dB
IF Rejection (84/98 MHz) 75 dB
Supurious Rejection (84/98 MHz) 75 dB
AM Suppression (IHF) 56 dB
Capture Ratio 1.0 dB
Usable Selectivity (1HF) 65 dB
Residual noise
0.14 mV
18
ace,
Signal-to-Noise Ratio (IHF)
Sensitivity (IHF, bar antenna) 18 uV/m
Selectivity (1,000 kHz) 20dB
Signal-to-Noise Ratio 50 dB (at 80 dB/m)
image Rejection (1,000 kHz) 40 dB
IF Rejection (1,000 kHz) 40 dB
Spurious Rejection (1,000 kHz) 50 dB
Total Harmonic Distortion
0.6% (at 80 dB/m)
Tuner Section Output Level/Impedance
FM (100% mod. at Rec Out)
450 mV/6.5 kQ2
AM (30% mod. at Rec Out)
120 ;mV/6.5 ka
GENERAL
Semiconductors
53 Transistors, 2 1Cs, 1 FET, 25 Diodes,
5 Zener Diodes, 3 LEDs, 2 Ceramic Filters
Power Supplies
AC 110/120/130/220/230/240 Vv, —
Switchable, 50/60 Hz
Australia AC 240 V, 50 Hz
Power Consumption
130W (Aust. 200 W)
Dimensions (W x H x D}
451 x 161 x 324
(17-3/4" x 6-1/ 3 x 12-3/ 4°")
Mono 77 dB
Stereo 71 dB
Total Harmonic Distortion |
Mono 100 Hz 0.15%
1 kHz 0.15%
6 kHz 0.3%
Stereo 100 Hz 0.25%
1 kHz 0.25%
6 kHz 0.8%
Intermodulation Distortion (IHF)
Mono 0.1%
Stereo 0.2%
Sub-Carrier Suppression 40 dB
Stereo Separation
50 Hz 30 dB
1 kHz 40 dB
10 kHz 30 dB
Frequency Response
50 Hz to 10 kHz +0.5 dB
30 Hz to 15 kHz +1.0 —3.0 dB
Weight
9 kg {20 Ibs.)
Muting Level
19.2 dBf (5 uV)
AM SECTION
Tuning Range
525 to 1,605 kHz
19
DAN
Before assuming that your CR-420 is faulty, check this trouble-shooting list. It details many steps
you can take yourself without having to call a service representative.
AUDIO SECTION
Fault
Cause
Cure
No power although POWER switch in ON (POWER
LED unlit).
AC power line not plugged-in to supply socket.
AC main fuse has blown.
Plug firmly into the supply socket,
Contact your service representative for a replacement.
No sound although power is connected.
Volume too low.
INPUT SELECTOR in wrong position.
input pin plugs incorrectly inserted, loose, ar disconnected.
Speaker connections faulty.
Both SPEAKERS push-buttons non-depressed..
Turn up volume.
Check and change as necessary.
Check and insert fully in the correct positions.
Check and make good.
Depress one or both (А, В, ог А + В).
Sound comes only, or mainly, from either L or R
speaker.
Speaker connections faulty.
Input connections faulty.
BALANCE contro! not properly adjusted.
Check and make good.
Check and make good.
Set to give correct stereo balance.
Sound sudden!y ceases during audition.
The protective circuit has gone into operation.
AC main fuse has blown,
Check for incorrect (too low) speaker impedances or short
circuits and correct.
H the fault persists, switch off and wait briefly before switching
on again.
Contact your service representative for a replacement.
Poor bass response and badly defined stereo image.
Speaker + and — connections are incorrect.
Reverse the connections to one speaker, not both.
A loud ‘hum’ is heard with or instead of, the record
when attempting PHONO audition.
Either the pin-plugs from the phono cartridge are not firmly
plugged into the input sockets, or the braided shielding wire
is defective.
Plug in firmly, replacing the defective shielding if necessary.
Check and make good the GND (ground) wire connection.
The volume control cannot be raised during record
audition without a loud ‘booming’ noise.
This is caused by feedback of sound from the speakers to the
phono cartridge stylus, and is called howling.’
Increase the separation between turntable unit and speakers,
avoiding locations directly in line with the speakers.
Bass and treble frequencies are unnaturally exaggerated.
The LOUDNESS volume control is set too low.
Turn to the FLAT position {fully clockwise) and reset main
and LOUDNESS volume controls according to the instructions.
Your tape recorder does not record the program you
are monitoring.
The REC OUT selector is not set to the required program
source.
Turn to the required setting.
20
TUNER SECTION
Fault
Cause
Cure
A persistent hum occurs when an AM station is tuned.
This modulation hum can affect whole areas where conditions
are unfavorable.
Sometimes changing the position of the CR-420 will give an
improvement.
intermittent crackling or continuous background
‘roaring’ on AM.
Atmospheric electricity or electrical storms, possibly fluores-
cent lighting or other electrical equipment.
Difficuit to eliminate, an external antenna and good ground
connection will give considerable improvement.
High pitched whistles, etc., particularly at night on
AM.
Signals from adjacent stations are interfering with reception.
The CR-420 is being operated too near a TV set.
Nothing can be done to cut out this interference completely
but try the HIGH filter.
Increase the separation between the TV and the CR-420
The desired station cannot be received at the correct
frequency on the dial.
The station strength may be low, and the MUTING circuit
may therefore prevent audition.
- Switch the FM MUTING from ON to OFF.
A stereo station is heard monaurally.
The amplifier MODE switch is set to MONO.
The FM MUTING switch is at OFF,
Push and release to the STEREO position.
Switch it ON.
Qccasional crackling interference (particularly with
remote, weak signal stations).
Electrical noise from automobiles, etc., or from other electrical
equipment.
Set up an external FM antenna, as high and as far from the
road as convenient: use coaxial cable. Fit an interference
suppressor to the offending item where possible.
Disturbing levels of ‘hiss’ noise when on FM stereo
stations.
FM stereo broadcasts are inherently more liable to this at
remote, low signal strength locations.
Local stations suffer from unclear, distorted sound.
Signal input from the antenna for these stations is too strong.
Set up an external FM antenna; if you are already using one,
orient it towards the station or replace with a more sensitive
array.
Alternatively or additionaily, listen with the FM MUTING
switch set at OFF.
Connect an attenuator between the FM antenna and the CR-420,
or turn the antenna away from the strongest (closest} station.
During stereo test transmissions, sounds which should
come from only one channel can be heard faintly over
the other.
This is known as crosstalk, and normally occurs to some extent.
Provided the sound level is very faint compared with the normal
level for that channel, no fault in indicated.
21
SINCE 1887
NIPPON GAKKI CO., LTD. HAMAMATSU, JAPAN
Printed in Japan 773%
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