Optonica sm 4646 h hb service manual

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= OPTONICA

SERVICE MANUAL

STEREO PRE/MAIN-
AMPLIFIER

MODEL

SM-4646H
(Silver Panel)

SM-4646HB
(Black Panel)

In the interests of user~safety the set should
be restored to its original condition and only
parts identical to those specified be used.

CAUTIONS:

In the case of this model SM«4646H/HB, since
the power supply voltage and current capacity
are relatively high, the potential remains at it

SPECIFICATIONS

GENERAL DESCRIPTION

Power source: ac. 110/220/240 V, 50/60 Hz
Powerconsumption: 520W

Semiconductors: 2-IC (Integrated circuit}
39.Transistor

87FET

25-Diode

lrLED

Width: 442 mm

Height: 144 mm

Depth: 363 mm

16 kg

Dimensions:

Weight:

MAIN AMPLIFIER
Circuit: Differential amplifier, complementary system, OCL
(Output Capacitoriessl
Continuous power output:
2 x95 W/4 ohms, Both channels driven
at 1 kHz, 0.05% distortion
2 x70 W/8 ohms, Both channels driven
at 1 kHz, 005% distortion
2 x85 W/40hms, Both channels driven
at 20 Hz ~20 kHz, 0.05% distortion
2 x60 W/8 ohms, Both channels driven
at 20 Hz ~ 20 kHz, 0.05% distortion
lntermodulation distortion:
0.05% at 95W
more than 50 (at 1 kHz, 8ohms)
5 Hz ~ 40 kHz at O,I%
distortion, 47.5 W
Input sensitivity and input im edance:
650 mV 50k ohms

Damping factor:
Power bandwidth:

PRE-AMPLIFIER

Equalizer amplifier:
FET-Differential amplifier, ICL (Input Capacitor-Less),
dual power supply (plus and minus)

Tone oontrol:
FET-Differential amplifier, ICL, Dual power

is without decreasing in about 20minutes even
after the power switch is turned off. When
handling or repairing this set, pay due attention
to this regard.

supply (plus and minus), 'NF type
Input sensitivity and input impedance:

PHONO I: 2.5 mV
22k ohms, 47k ohms,
100k ohms
PHONO 2: 2.5 mV ~ 5 mV/47k ohms
AUX: 150 mV/47k ohms
TUNER: 150 mV/47k Ohms

TAPE PB I and 2:
150 mV/47k ohms
TAPE PB (DIN socket) i and 2:
150 mV/47k ohms
Output level and load impedance:
REC l and 2: 150 mV/47k ohms
REC 1 and 2 (DIN socket)
30 mV/82k ohms
Phono overload: 350 mV IRMS, 1 kHz)
R IAA curve deviation:
1 0.3 dB (20 Hz ~ 20 kHz)
Frequency response:
5 Hz ~ 70 kHz 11.5dB (TUNER, AUX,
TAPE PB)
Signal to noise ratio:
PHONO I and 2: 70 dB
AUX, TUNER, TAPE PB: 90 d8
Tone control:

Bass: t 10 dB (at 100 Hz, turnover 600 Hz)
i 10 dB (at 50 Hz, turnover 300 Hz)

Treble: i 10 dB (at 10 kHz, turnover 1.5 kHz)
1 lOdB (at 20 kHz, turnover 3kHz)

-3dB at 30 Hz, i2dB/oct.
-3dB at IO H2, 12 dB/OCI.
-3dB at 7 kHz, GdB/oct.
-3dB at 20 kHz, 6dB/oct.
-20 dB

Low cut filter:
High cut filter:

Audio muting:

Specifications of this model are subject to
change without prior notice.

SHARP CORPORATION OSAKA, JAPAN

SM-4646H

SM-4646HB

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LAYOUT OF FRONT PARTS

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Headphones jack
Speakers selector
Low cut filter switch

Power switch

Power source/circuit protection indicator
Bass control

Turnover frequency selector for bass control
Tone control defeat switch

Turnover frequency selector for treble control
Treble control

Volume control

Input level control (for phone 2)

Input impedance selector lfor phono 1)
Function selector

High cut filter switch
Loudness switch
Balance control
Muting switch

Mode selector

Tape dubbing switch
Tape monitor switch

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LAYOUT 0F REAR PARTS

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Phono input jacks l (3) Recording output jacks 2
Phone input jacks 2 ® Output lacks of preamplifier
Tuner input jacks (3:32 Input jacks for mainramplifier
Auxiliary input jacks 8341 Fuse holder
Record/playback socket l 65 Earth terminals

Recording output jacks 1 Speaker terminalsrB
Record/playback socket 2
Tape playback jacks 2

Tape playback jacks 1 6% Speaker terminalsrA
7

Mains voltage selector

N

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Figure 1

Figure 2