Sony HP-210 User manual

TABLE OF. CONTENTS
Title Page
SERVICING NOTES ssi visas earnctialaenh bata alana ater MES 1
SECTION 1 TECHNICAL DESCRIPTION
1-1. Technical Specification ..0.........2:cccccsceeeecseserececcseeersssencessecessesensees 2~3
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SECTION 2. DISASSEMBLY AND REPLACEMENT PROCEDURES
2-1. Tools: Requited 9 scccsi.c. cscs ccsiecasieceschovsesivevseoventcceccescaceaseseees 10
2-2. Hardware Identification Guide ; 10
2-3, Top Cover Removal .....ci.cccccccusscsenseccoccessenssonsocnessonctoceccecssesecscasaaees 11
2-4. Record-Changer Removal .00.........ccccsessssseceeseececceceeceneeseneecees aieeesetes 11
2-5. Front Panel Removal .........ccccccsecscsssrecccedsccssssccsssssssccssssonssssceensseses 12
2-6. Wooden Case Removal ..........cscccssecseseseseeessesseeesseeesneesaseneneessneesenes 13
2-7. Dial-Cord Restringing .0........scesseseesseesseeesseesneeeeesneennecsensenseee
2-8... Mechanical Dial Calibration .............cscsscssesscssecsssnsearsnseneiosenesotenees
2-9. Pilot Lamp Replacement sacedbesccen seSesevss dasnwoagenceeceesdegevassessaeserses seseeeed .
2-10... Control and Swtich Replacement ..........s200% sSecreacbeeoos
QTL. POR RemiOval: <scarssvsiaaspandetarinndertss
: 2-12. Ac Outlet Replacement .o..c.cccccesseeseeeeeeee
'2+13. Power Transistor Replacement —...........cc00.
Q- 14: Chassis LAV OME: ssccosticcussenceshevcsothenectouasiziopas ee
SECTION: 3 " ALIGNMENT AND ADJUSTMENT PROCEDURES
3- i FM I-f and: Discriminator Alignment ......... baatlenis 21
3-2... FM Frequency ‘Coverage Alignment 2122 9,23
RB FM Tracking Alignment. ; re
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3-5; AST ‘Frequency. Coverage and Tracking Alignment. 26~ ~. 28
ae Power-Amplifier Adjustments ‘ . 220 29
"RECORD. CHANGER ‘SERVICING. PROCEDURES 7
1, * Line‘Frequency Change-... ies
, ,Line-Voltage Change. wteee 30
: Cartridge Replacement
Stylus. Tip Replacement
aa Diagram -— Power ee
a Power Supply Board — oiu..eeieccccsssscesssecssrsccsesessseceecsseens 36 ~ 37
6-4. Mounting Diagram — Preamplifier Board — oesovensoseserssnsecsseneses 38 ~ 39
6-5. Schematic Diagram — Tuner and MPX Section — ............. 41 ~ 42
6-6. Schematic Diagram — Audio Amplifier Section — ........... 43 ~ 44
SECTION 7 EXPLODED VIEW ......000 je desu cotevcuudensesysbseBonhteckocssees 45 ~ 47
SECTION 8 ELECTRICAL PARTS LIST .o.ccccccccccscsssoss RCRA CON 48 ~ 52

SERVICING NOTES
__.1,_Be_certain that the lead wires (blue) for the dial lamp are affixed to the front subchassis with electrical tape, _
otherwise hum will be picked up at the preamplifier stage. See Fig. A.
Be certain that the discriminator transformer shield is reinstalled, otherwise hum will be picked up from the
record changer motor. See Fig. B.
In this set, “‘wire-wrap” connections are employed as shown in Fig. C. In case a-wire breaks, simply solder
the lead wire directly to the terminal post.
Wire-wrap connection cannot be properly made by hand.
Care should be taken not to cut too deep when removing the insulation from wire.
Even the slightest nick in the copper wire will weaken the wire enough to eventually cause a break at that
point. Use a soldering iron to remove the insulation.
electrical tape
Fig. A Affixing lead wire
shield
cover
terminal
post
Discriminator
--— transformer
IFT201
Fig. B {FT201 and shield cover . Fig. C “Wire-wrap” connection

SECTION 1
TECHNICAL DESCRIPTION
1-1, TECHNICAL SPECIFICATIONS
Technical specifications for the HP-210 are listed
in Table 1-1.
TABLE 1-1. HP-210 TECHNICAL SPECIF ICATIONS
Fm Tuner Section
Antenna:
Frequency range:
Intermediate
frequency:
Usable
sensitivity:
Sigtaltecnpise ratio:
Capture ratio:
Selectivity:
Image rejection:
I-f rejection
Spurious signal
rejection:
A-m suppression:
Frequency response:
Harmonic
distortion:
Fm-stereo
separation:
19-kHz, 38-kHz
suppression:
300 ohms balanced
87.5 to 108 MHz
10.7 MHz
2.5uV (S/N = 30 dB)
1.6uV (S/N = 20 dB)
65 dB, IHF
1.5 dB, IHF
50 dB, THF
45 dB
80 dB
49 dB
50 dB
50 to 15,000Hz +2 dB
Mono: 0.5% at 400Hz
Stereo: 0.8% at 400 Hz
Greater than 36 dB at 400 Hz
45 dB
A-m Tuner Section
Frequency range:
Intermediate
frequency:
Sensitivity:
Signal-to-noise
ratio:
$30 to 1,605 kHz
455 kHz
50 dB/m, built-in antenna
10zV, external antenna
50 dB
____ Image rejection: _
_ 40 4B at 600 kHz
I-f rejection:
Harmonic
distortion:
35 dB at 1,400 kHz
40 dB at 1,000 kHz
0.8%
Audio Amplifier Section
Dynamic power:
(IHF constant power
supply method)
Music power output:
(EIA)
Continuous RMS
power:
Harmonic
distortion:
Frequency
response:
Input sensitivity
and impedance:
Signal output:
Signal-to-noise
tatio (IHF (B)
network):
Tone controls:
. Loudness:
28 watts, both channels
operating, 8 ohms, 1% THD
36 watts total
10 watts, per channel, both
channels operating, 8 ohms
Less than 1.0% at 1 kHz at
rated output :
AUX: (+3 dB)
TAPE: | 30 to 50kHz
at 1-watt output
PHONO: 600 mV, 1M ohms
TAPE: 400mV, 100k ohms
AUX: 250 mV, 100k ohms
REC/PB: 400 mV, 100k ohms
REC OUT:
250 mV, 10k ohms
x REC/PB: 30mV, 80k ohms
PHONO: greater than 58 dB
TAPE:
AUX: greater than 66 dB
BASS: +10dB at 100 Hz
TREBLE: +10dB at 10kHz
8 dB up at 50Hz
4dB up at 10kHz
(VOLUME-control
tion: 30 dB)
attenua-
% : General Export Model only

~~Record changer: --"-~
Phonograph Section
BSR -C-116, ~four~-speeds—
(1673,
3331/3,
45,
78
rpm)
Cartridge: SONY Crystal Cartridge
VX-18P
Stylus: SONY Diamond Stylus
ND-120P
Number of records
played automati-
cally: Up to 5 LP records
Speaker Section (SS-210)
System: 2-way (61/." (16 cm) woofer,
2” (5 cm) tweeter)
Impedance: | 8 ohms
Dimensions: 91/," (width) x 15” (height)
x 83/3" (depth)
235 mm (width) x 380 mm
(height) x 213 mm (depth)
Net weight: 6lb 10 0z (3.0 kg)
Shipping weight: 18 Ib 120z (8.5 kg) per
pair in shipping carton
General
50 watts
x 75 watts
120V ac
x 100, 120, 220, 240V
50/9 Hz ac
Power consumption:
Power requirements:
Dimensions:
x 161/g" (depth)
421 mm (width) x 241 mm
(height) x 410 mm (depth)
241b 80z(11.1kg)
30lb 1402 (14kg)
Net weight:
Shipping weight:
%* : General Export Model only
1-2. CIRCUIT ANALYSIS
The following describes the functions of all
stages and controls. The text sequence follows
signal paths. Stages are listed by transistor reference
designation at the left margin; major components
are
also
listed
in
a
similar
manner.
Refer
to
the
block
diagram on page 7 and the schematic diagrams on
pages 40 to 43.
16%16" (width) x 91/2" (height)
Stage/Control
“Fm Front-End ~
Balun Bi01
Rf amplifier
Q101
Local
oscillator
Q103
AFC circuit
D101, D102
C115, C119,
R113, R114,
RIS
Function
This transformer matches 300-
ohm twin lead to the fm front-
end’s input stage.
The rf amplifier and tuned cir-
cuits. provide high sensitivity,
good image rejection, and good
selectivity. Field-effect transistor
Q101 is ideally suited for this
job since it has low-noise charac-
teristics and a wide dynamic
range. The latter characteristic
results in very low-cross modula-
tion products. Antenna coil
L101 is tapped to match the
low-input impedance of the
common gate amplifier.
This oscillator supplies injection
voltage to the mixer via oscil-
lator coil L103. The circuit is a
modified Hartley oscillator with
feedback applied to the emitter
from a tap on tank coil L103.
An automatic frequency control
circuit is incorporated in the
oscillator to provide easy recep-
tion of fm signals. Tuning is
usually performed by ear, that
is, turning the tuning knob and
setting it to the position where
the clearest sound is heard. How-
ever this is rather difficult job.
By using afc, the difficulty of
tuning and frequency drift in the
local oscillator can be elimi-
nated.
The principle of afc operation is
as follows:
When the tuner is correctly
tuned, the intermediate fre-
quency is kept 10.7 MHz and no
dc correction voltage is produced
by the ratio detector as shown
in the ‘“S” curve response
Fig. 1-1. So, the voltage applied
to diode D101 is determined
solely by the positive fixed -
reverse bias voltage supplied by
zener diode D102.
Now assume that the local oscil-

Stage/Control
Mixer Q102
Fm I-f Amplifier
I-f amplifiers
Q201 to Q204
I-f output
Q205
Function
lator frequency changes by taf.
This means that the new inter-
mediate frequency is 10.7 MHz
+af. See Fig. 1-1.
As the result a positive dc com-
ponent is fed back to the anode
of D101, decreasing the reverse
voltage to it, and making D101’s
barrier capacitance increase. This
decreases the local oscillator’s
frequency since the series circuit
composed of C119 and D101 is
connected in parallel with the
tank circuit of the local oscil-
lator. Conversely, if the local
oscillator frequency decreases, a
negative dc voltage is fed back to
D101, increasing the local oscil-
lator frequency.
Rf signals and local-oscillator
voltage are heterodyned in the
base-emitter junction of mixer
Q102 to produce 10.7-MHz i-f
output signal. Transformer IFT-
._ 101 and capacitors C105 and
C106 form a high “C’’, pi-net-
work bandpass
passes the i-f output and pro-
vides a path to ground through
~ C105 and C106 for the other
heterodyne products and oscil-
lator harmonics.
The i-f amplifier stages consist
of two pairs of direct-coupled
amplifiers that provide essen-
tially flat response. The
selectivity of this section is
determined by two-pairs of
filters (CF201, CF202, CF203,
and CF204) in the inter-stage-
coupling path. Each of these
filters is a two-section ceramic
filter that operates in the
“trapped-energy” mode. The
filters provide extremely sharp
skirt selectivity and flat response
inside the pass band. These
filters determine overall selec-
tivity in the fm tuner.
Q205 provides power to drive
the ratio detector.
filter, which ©
Stage/Control
~ Ratio detector
IFT201, D201,
D202
MPX Decoder
SCA trap coil
L301, C306
19-kKHz
amplifier Q303
Fig. 1-1
Function
IFT201: and diodes D201 and
D202 form a balanced ratio de-
tector that transformes the fre-
quency-modulated signal into an
audio signal. Output appears
across C207.
The composite signal containing
monaural information from 0 to
15 kHz, the 19 kHz pilot carrier
and the stereo signal at 38 kHz
+15 kHz is fed to the MPX de-
coder through a trap consisting
of L301 and C306. This trap
removes the -unwanted SCA
signals (67 kHz) to feed a clean
composite signal to the base of
Q303.
This stage serves two functions.
It extracts the 19-kHz pilot
signal by means of a tuned
circuit at its collector, and pro-
vides a low-impedance source of
composite stereo signal (without
_the pilot carrier) at its emitter.
Series-resonant circuit in the
emitter circuit eliminates the
19-kHz pilot signal from the
composite stereo signal.
local oscillator freq.
10.7 MHz
RF signal
“S” curve
response
% Af: frequency drift
Lacal oscillator frequency drift and
- afc voltage relation

7
all
Stage/Control
“Frequency”
doubler
D301, D302
38-kHz
amplifier
Q305
STEREO-lamp
circuit
Q304, Q305
Multiplex
demodulator
D303, D304
D305, D306
Function
Signals developed at the collec=
tor of Q303 are transformer-
coupled to a full-wave rectifier
consisting of D301 and D302.
The output of this rectifier is
not filtered, resulting in two
positive pulses’ for each input
cycle. Thus the 19-kHz pilot-
carrier frequency is effectively
doubled by D301 and D302.
However, the waveform is not
sinusoidal at the base of Q305.
The 38-kHz pulses produced by
D301 and D302 are amplified by
Q305. The tank circuit at the
collector of Q305 is tuned to
38 kHz to restore these pulses to
a sinusoidal waveform for use
as a switching signal. This signal
is transformer-coupled to the
bridge-type demodulator to
supply sampling drive for the
demodulator:
The STEREO indicator lights
when an fm-stereo signal is
received. The emitter of Q305
is connected to the base of
Q304, which is normally cut off.
The circuit operates as follows:
When a composite stereo signal
is applied to the multiplex de-
coder, the 38-kHz pulses pro-
duced at the output of the
frequency doubler yield a higher-
average current flow through
Q305. This forces Q304 into
conduction, lighting STEREO
indicator lamp PL1.
The demodulator circuit em-
ploys four diodes in a balanced
bridge arrangement. This system
has the advantage of cancelling
residual rf components (38-kHz
signal, some 19-kHz signal, and
higher-order harmonics of these
frequencies). “L” and ““R” com-
ponents are developed at each
side of the bridge as the result
of demodulation, when the
receiver is operated in the stereo
mode. In the monaural mode,
diodes D303 and D304 are
Stage/Control
De-emphasis
circuit
C319, C320
Twin-T filter
C321, C325,
R335, R332,
R336, C324
(C322, C326
R334, R333,
R337, C323)
A-m Tuner
Local oscillator
Q404
Mixer Q401
I-f amplifier
Q402
Ceramic filter
CF401
Function
forward biased by supply volt-~
age through the STEREO lamp,
R321, R326 and R327, so these
diodes merely act as small resist-
ances. Under this condition, the
monaural signal is applied to
both “L” and “R” audio ampli-
fiers.
These capacitors provide the
roll-off at high audio frequencies
necessary to compensate for pre-
emphasis at the transmitter.
This filter eliminates the 38-kHz
carrier, thereby preventing
carrier leak.
This stage supplies injection volt-
age to the mixer via L402. The
circuit is a modified Hartley
oscillator with feedback applied
to the emitter of Q404 from the
tap on the secondary winding
of oscillator coil L402.
Incoming rf signals and !ocal-
oscillator voltage are hetero-
dyned in the base-emitter
junction of Q401 to produce
the 455-kHz output.
IFT401 is a transformer tuned
for 455 kHz. It develops the i-f
signal, and provides a path to
ground through bypass capacitor
C405 for the other heterodyne
products. The low-impedance
output winding of IFT401 pro-
vides link coupling to if
amplifier Q402.
This stage is basically an RC-
coupled amplifier. The selec-
tivity of the stage is determined
by a double ceramic filter
(CF401) in the interstage-coupl-
ing path. This filter provides
extremely sharp skirt selectivity
inside the pass band.

Stage/Control
L-f amplifier
Q403
Age circuit
D402, R415,
C426, R428,
C425, R412,
R427, C422,
C421, R401
Audio Amplifier
Function
‘This circuit provides the power
to drive envelope detector D401.
The positive de component at
the cathode of diode D402 is fed
back to the base of Q403, and
from there to Q401 to control
its gain. The time constants of
the age components filter audio
variations out of the agc voltage.
Since the audio-amplifier section contains two
identical amplifier chains, only the left channel will
be described.
MODE switch
82
Preamplifier
Q501, Q502
Equalization
circuit
R505, C502,
R506, C501,
R503
Feedback
circuit
‘R519, C510
Attenuator |
R501, R502,
R507, R508
In the STEREO position of S2,
left and right input signals are
routed to their respective ampli-
fiers. In the MONO position, the
left and right signals are added.
The sum is then fed to both
amplifier channels.
This stage amplifies the small
signal provided by the phono
cartridge, tape recorder, to the
level required at the input of
the power-amplifier section. The
preamplifier uses a complicated
negative-feedback technique that
provides stable operation during
temperature changes, and good
amplification at low-frequencies.
It also applies the audio signal
to the REC OUT jack for
optimum recording.
Phono equalization is achieved
by these filter circuits to obtain
a flat response.
In the any position of the
FUNCTION | switch, feedback
is applied through R519 and
C510 to provide a flat response
in the preamplifier. Be sure to
use replacement components
with the exact same values.
Signal applied to the TAPE or
AUX input jack is attenuated
by these resistors. This allows
the HP-210 to accept signals of
Stage/Control
Channel
separation adj.
R524
BASS control
RV531
TREBLE control
RV532
Loudness circuit
R536, R537,
C535, C536
VOLUME
CONTROL
RV701
Predriver
Q503
Ac balance
adj.
RV541
Phase inverter
Q504
Function
about 400 mV at the TAPE and
250mV at AUX input jack,
and amplify them without
distortion.
This network connects the emit-
ters of preamplifiers Q501 and
Q601 only when the FUNC-
TION switch is set to the FM
position. It provides a form of
negative feedback between the
left and right channels. Any
residual inverted “L” signals in
the “‘R” channel are cancelled
out by the “L” signal from the
“L” channel. The same is true
of residual “R” signals in the
“L” channel.
This control has a range of
+10dB at 100Hz. i
This control has a range of
£10dB at 10kHz.
This compensates for the charac-
teristics of the human ear, whose
tonal response varies according
to the loudness of the sound
being heard. High- and low-
frequency components are in-
creased in ‘inverse proportion
to the VOLUME control setting
by means of R536, R537, C535
and C536.
The level of signal applied to
the power amplifier is deter-
mined by the setting of RV701.
Q503 amplifies the signal to the
level required at the power
output stages.
Controls the bias current of
Q503 and Q504 to the point
where positive and negative half
cycles are simultaneously
clipped when increasing the
input signal.
It also affects the rated output
power.
Stage Q504 has two oppositely-
phased outputs to drive the
- power-output stages in push pull.

Stage/Control
Positive bias
power supply
D501, D502,
D503
De bias adj.
RV542
Negative-
feedback loop
R557, R556
C547
Drivers
Q505, Q506
Power
amplifier
Q507, Q508
Function
These diodes are forward biased
by supply voltage through R564
and provides stabilized dc volt-
age of about 1.8V, supplying
idling current for Q506, Q606.
Controls the idling current in
Q505, Q506, Q507 and Q508
to eliminate crossover distortion
at small signal levels.
These components provide nega-
tive-feedback voltage from the
output of the power amplifier
to the emitter of Q503.
These transistors operate as
emitter followers to provide
the current swings demanded of
the output stages for full output.
These SONY silicon transistors
have been specially manu-
factured to drive the speaker
system. Output is coupled to
the speakers through C548.
Stage/Control
Power Supply —
Voltage
regulator
Q509, Q510
Function
DC output from rectifier D504,
D505 is filtered by C701 and
applied to series regulator Q510.
Q509 compares a sample of
the output voltage picked off
across R568. A change in
output voltage is detected at
the base of Q509 and there-
fore alters its collector voltage.
Since the collector of Q509 is
directly coupled to the base of
Q510, the change in output
voltage alters the conduction
of Q510 by the amount neces-
sary to maintain the output
voltage constant. An increase
in output voltage causes an
increase in the impedance (de-
crease in conduction) of Q510,
and vice-versa. The dc output
voltage supplied to the tuner is
thus stable.

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2-5.
FRONT PANEL REMOVAL
Remove the top cover as described in Procedure
2-3.
Remove the all control knobs by pulling them
off. ”
Remove the HEADPHONE jack by using jack
driver or pliers.
Refer to cross sectional view Fig. 2-4, lift the
bottom part of the front panel up while pulling
it forward as shown in Fig. 2-5. This frees
the lower catch.
Press the top of the front panel as shown in
Fig. 2-6. This frees the front panel.
To reassemble the front panel, reverse the
foregoing procedures.
ee
Fig. 2-5.
upper :
Fig. 2-6.
Front panel removal (1)
Fig..2-4. Cross sectional view of front panel
Front panel removal (2)
= 125=>
lower catch

2-6. WOODEN CASE REMOVAL
1.
Remove the record changer as described in
Procedure 2-4.
Remove the two self-tapping screws (® B 3x6)
securing the motor board bracket to the front
subchassis as shown in Fig. 2-8.
Remove the six self-tapping screws (® B 3x6)
from the bottom and one self-tapping screw
(® B 3x16) from the rear of the wooden case
ie as shown in Fig. 2-7.
Carefully lift the wooden case straight up.
self-tapp
®B 3x16
self-tapping |:
Screws
® B 3x6
2-7. DIAL-CORD RESTRINGING
Preparation
1. Remove the front panel and wooden case as
described in Procedures 2-5 and 2-6.
2. Cut a 71-inch (1800mm) length of 1/64-inch
(0.5 mm) diameter dial cord.
3. Tie the end of the cord to a spring as shown
in Fig. 2-9.
4. Rotate the tuning-capacitor drive drum fully
counterclockwise (minimum capacitance posi-
tion). ;
Fig. 2-9. Tying square knot in the coil spring
Fig. .2-8. _Woodeén case removal

----Procedure-----
While referring to Fig. 2-10, proceed as follows:
Hook the spring to one hole of the drive drum
as shown in Fig. 2-11, and then squeeze it.
Run the cord through the slot in the rim of
the drum and wrap a counterclockwise turn
in the inner side groove. See Fig. 2-12.
Run the cord over pulley “A”, and then wrap
three counterclockwise turns around the tuning
shaft.
Run the cord over pulleys “B’’, “‘C” and “D”
then wrap three counterclockwise turns around
Fig.
2-11.
-
Coil
spring
installation
pulley “C”
@
aD
pulley “B”
the
drum
from
outer
groove
to
inner
groove
as
shown in Fig. 2-12.
Pass
the
doubled
end
of
the
cord
through
the
eyelet
(See
Fig.
2-13),
then
hook
it
to
the
spring as shown in Fig. 2-14.
Tighten the cord, then squeeze the eyelet so
that the spring is under tension.
Make
a
knot
in
the
cord
end
to
keep
it
from
slipping
out
of
the
eyelet.
See
Fig.
2-13.
After
completing
the
dial-cord
stringing,
make
sure
that
the
tuning
system
works
properly.
Apply
a
drop
of
contact
cement
to
the
knots.
Perform
the
mechanical
dial
calibration.
Fig.
2-12.
Wrapping
the
dial
cord
pulley “A”
tuning shaft (three counterclockwise turns)
Fig.
2-10.
Dial
cord
stringing
— 14 —

2-8.
Fig. 2-14. End of dial cord stringing
MECHANICAL DIAL CALIBRATION
Note: This is required after replacing the dial
cord.
Put the dial pointer on the cord as shown in
Fig. 2-15, and move it to a position where the
pointer
coincides
with
the
guide
hole
provided
in the front subchassis as shown in Fig. 2-16,
when the tuning capacitor is set to the
maximum capacitance position.
Hook the dial pointer on the dial pointer
restricting cord as shown in Fig. 2-16.
Fig. 2-15. Dial pointer installation
dial pointer
=e dial pointer restricting cord
Fig. 2-16. Mechanical dial calibration

2-9. PILOT LAMP REPLACEMENT
Prepare for replacing any of the pilot lamps
by removing the record changer as described in
Procedure 2-4.
Stereo Lamp
1. Pull the lamp from its rubber holder.
2. Unsolder the defective lamp leads from the
connecting terminals on the tuner board, and
then install the new lamp.
Dial Lamp
1. Remove the front panel as described in
Procedure 2-5.
2. Pry out the defective lamp, and then install
the new one.
2-10. CONTROL AND SWITCH REPLACEMENT
Prepare for replacing any of the controls or
switches by removing the front panel as described
in Procedure 2-5. :
TONE Controls
1.
Remove the hex nuts that secure the BASS and
TREBLE controls to the front subchassis as
shown in Fig. 2-17.
Cut the two lead wires connecting between the
tone control board and preamplifier board.
Carefully remove them along with the tone
control circuit board.
Cut each lug of the defective control on the
board to remove the part.
VOLUME
control
SPEAKER
Sw
HEADPHONE SW
jack
Fig. 2-17.
control
5.
6.
Unsolder and remove the clipped lugs, and
clean out the holes in the circuit board.
Install the replacement control.
FUNCTION Switch (slide/rotary switch)
1,
TREBLE
control
GS
Remove the hex nut sécuring it to the front
subchassis as shown in Fig. 2-17.
Cut the two lead wires connecting between
preamplifier board and tone control board as
shown in Fig. 2-18.
Remove the lead wires from the clamp/PCB
support one by one and then unhook the fiber
support as shown in Fig. 2-18. This frees
the preamplifier board.
With a soldering iron having a solder-sucking
tip, clean the solder from each lug of the
defective switch and the printed board.
Install the replacement switch.
Fig. 2-18. Preamplifier board removal
self-tapping screw
@®B 3x6
FUNCTION
Sw
Control and switch replacement

VOLUME
Control,
SPEAKER
Switch
and
HEADPHONE
Jack
1.
Remove
the
hex
nuts
that
secure
them
to
the
front
subchassis
as
shown
in
Fig.
2-17.
2.
Unsolder
the
lead
wires
from
the
defective
parts,
and
then
install
the
replacement
parts.
MODE and POWER Switches
1.
Remove
the
two
screws
securing
the
switch
to
the
front
subchassis
as
shown
in
Fig.
2-17.
2.
Unsolder
the
lead
wires
from
the
defective
switch,
and
then
install
the
replacement
switch,
2-11. PCB REMOVAL
Prepare
for
removing
any
of
the
printed
circuit
boards
by
removing
wooden
case
as
described
in
Procedure
2-6.
Tone
Control
and
Preamplifier
Boards
1.
Refer
to
the
tone
control
replacement
pro-
-
cedures
for
tone-control
board
removal
as
described
in
Procedure
2-10.
2.
Refer
to
the
function
switch
replacement
pro-
cedures
for
preamplifier
board
removal
as-
described
in
Procedure
2-10.
See
Fig.
2-18.
Tuner and MPX Board
1.
Fasten
the
dial
cord
to
the
drum,
pulley
“A”
pulley “D”
pulley “A”
vie. s)
A
Remove
two
lead
wires
(red and orange) from
‘| this clamp.
Power amp board removal
Crt
MPX board
and pulley ‘“D” ‘with cellophane tape.
This helps you to restring the dial cord.
2. Unsolder the fm and a-m antennal lead wires
from the antenna terminals.
3. Remove the three self-tapping screws (® B 3x6)
securing the tuning capacitor and PCB brackets
to the chassis as shown in Fig. 2-19. This
frees the tuner and MPX board.
Power Amplifier Board
1.
Remove
the
two
lead
wires
(green
and
black)
from
the
power
amplifier
PCB
support
and
the
two
lead
wires
(red
and
orange)
from
the
tuner
and
MPX
PCB
support,
and
then
remove
the
two
self-tapping
screws
securing
the
heat
sink
to
the
chassis
as
shown
in
Fig.
2-19.
This
-
frees
the
power
amp
PCB.
2.
Insert
the
tabs
of
the
PCB
into
the
opening
in
the
chassis
as
shown
in
Fig.
2-20.
This
helps
in
replacing
ot
checking
the
com-
ponents
mounted
on
PCB.
2-12.
AC
OUTLET
REPLACEMENT
|
1.
Remove
the
wooden
case
as
described
in
Procedure
2-6.
2.
Pry
out
the
socket
retaining
clip
with
a
screw-
driver
as
shown
in
Fig.
2-21.
This
frees
the
ac
outlet.
3. Install the replacement ac outlet.
Remove two lead wires
(black
and
green)
from
this clamp.
Power
amp
board
remova
said
:
~
Fig.
2-19.
PCB
removal
oF

|________2-13.. POWER TRANSISTOR REPLACEMENT
Fig. 2-20. Power amplifier board removal
screw
Oriver
ac outlet
Fig. 2-21. Replacing the ac outlet
2-14. CHASSIS LAYOUT
tuner and
MPX board
preamplifier board TONE control
board
1.
2.
REC/PB connector
{General Export
Model only.
1s
Remove the power amplifier board as described
in Procedure 2-11.
Remove the two screws and retaining. bracket
securing the defective power transistor to the
heat sink and PCB.
Unsolder the leads of power transistor, and
then install the new one.
When replacing the power transistor, apply a
coating of a heat-transferring grease to both
sides of the insulating mica washer. Any
excess grease squeezed out when the mounting
bolts are tightened should be wiped off with
a clean cloth. This prevents it from accumu-
lating conductive dust particles that might
eventually cause a short.
~—=————— amplok
fuse 1.6A
_C701
1,000 pF
voltage selector
(General Export
Model only,

| SECTION 3
ALIGNMENT
AND
ADJUSTMENT
PROCEDURES
3-1. FM I-F AND DISCRIMINATOR
ALIGNMENT
CAUTION
The ceramic filters in the fm i-f circuit are
selected according to their specified
center frequencies and color coded as
shown in Fig. 3-1 and listed in Table 3-1.
Check the color code of the filters to
identify the same center frequency when
replacing any of these filters.
TABLE 3-1.
FM LF CERAMIC FILTERS
Part No. Color Specified Center Freq.
1-403-562-11 red 10.70 MHz
1-403-562-21 black 10.66 MHz
1-403-562-31 white 10.74 MHz
1-403-562-41 green 10.62 MHz
1-403-562-5 1 yellow 10.78 MHz
color spot
Fig.
3-1.
Color
dot
on
ceramic
filter
| “setts
WN
Interruption of fm or a-m local
oscillator operation
Fig. 3-2.
a {9 —
Note: Two methods of i-f discriminator align-
ment are available, sweep generator
alignment and signal generator align-
ment. You can use either of them. In
either case, the local oscillator should be
killed. To stop the local oscillator’s
operation, remove the shield cover over
the local oscillator capacitor, if néces-
sary, and then: shunt the oscillator
capacitor with a 0.02uF capacitor.
See Fig. 3-2. :
Sweep Generator Alignment
Test Equipment Required
1. .10.7 MHz sweep generator
2. © Oscilloscope
3. Ceramic capacitor, 0.02uF
4. Alignment tools
Preparation
1. Remove the record changer as described in
Procedure 2-4.
2. Connect the input cable of the oscilloscope
with alligator clips to R221 and ground on
the fm a-m tuner circuit board, and solder
a 0.024F capacitor across these clips, as shown
in Fig. 3-3.
3. Connect the output cable of the sweep gener-
Fig. 3-3.
ator across CV102 on tuner and MPX board.
Use alligator clips and make the connection
through a 0.02zF coupling capacitor as shown
in Fig. 3-4.
é
Fm discriminator output connection

ay —Procedure-——--— ie aes SS meres ~
1.
With
the
equipment
connected
as
shown
in
Fig.
3-5,
set
the
sweep
generator’s
controls
as
:
follows:
To
sweep
or
rf
generator
;
: :
Center
frequency.........
Specified
frequency
of
ceramic
filter.
See
Table
3-1.
Sweep
width
.......0000...
1
MHz
2.
Set
the
receiver’s
controls
as
follows:
FUNCTION
switch
.....
FM
AUTO
STEREO
VOLUME
control
......
Minimum
3.
Adjust
the
oscilloscope
controls
to
provide
a
visible
indication.
Note: Two or three traces will be observed on
the oscilloscope as the center frequency
of the sweep generator varies. The trace
you are looking for has the largest
amplitude. Once you get it, decrease the
sweep generator output low enough to
obtain rather noisy output.
4.
Turn
the
top
core
(secondary
side)
of
discrimi-
nator
transformer
IFT201
with
an
alignment
tool
to
obtain
the
“S”
curve
response,
and
equalize
the
positive
and
negative
peaks
of
the
“‘S”
curve
response,
as
shown
in
Fig.
3-6.
Fig. 3-6. “S” curve response
5.
Adjust
i-f
transformer
IFT101
(see
Fig.
3-11)
and
primary
side
of
discriminator
transformer
(IFT201
bottom
core)
to
obtain
a
maximum-
amplitude
“‘S’’
curve
response.
.
oscilloscope
HP-210
————
902m
EN
aur
|
10.7
MHz
ae
sweep
|
evro2
R221
V H
|
generator.
o
O°
i
o
ee
ee
Fig. 3-5. Test setup for discriminator alignment by sweep generator