Optonica sa 3131 h service manual

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= OPTONICA

SA-3131 H

SERVICE MANUAL

fl (MONICA

5A M "W

MODEL SA-313m

Inéthe inteIests of user-safety the set shuuld be Icstored to its original condition and only parts
identical to those specified be used.

INDEX TO CONTENTS I

1. SPECIFICATIONS .......................... 2 10.AL1GNMENT INSTRUCTIONS
2. FEATURES ............................... 2 REQUIRED EQUIPMENT .................. 17
3. PREPARATION FOR USE .................... 3 AF ALIGNMENT ........................ 18
4. DISASSEMBLY ............................ 3 AM IF ALIGNMENT ..................... 18
5. DIAL CORD STRINGING .................... 4 MW RF ALIGNMENT .................... 20
6. FRONT PARTS LAYOUT .................... 5 LW RF ALIGNMENT ..................... 21 I
r' 7. REAR PARTS LAYOUT ..................... 5 FM ALIGNMENT ........................ 22 .
81 BLOCK DIAGRAM ...................... 6~7 FM TUNING METER ADJUSTMENT AND I
9. CIRCUIT DESCRIPTION DISTORTION FACTOR ADJUSTMENT _ .23 I
AM SECTION ........................... 8 FM MUTING ADJUSTMENT AND FM STEREO I
FM RF SECTION ........................ 8 V.C.O.,SEPARATION ADJUSTMENT . . .23 I
FM IF SECTION ......................... 9 ADJUSTMENT OF AIR CHECK CAL ......... 24 I
FM DETECTION SECTIONS (Quadrature Detector) .9 11.EQUIVALENT CIRCUIT OF I
FM STEREO DEMODULATOR SECTION ...... 10 INTEGRATED CIRCUIT ...... 25 ~28 I
AIR CHECK CALIBRATION CIRCUIT ........ 11 12.SCHEMATIC DIAGRAM ................. 29~ 30 I
FM MUTING CIRCUIT ................... 11 l3_WIRING SIDE OF P.W. BOARD ........... 31'~ 36 I
LOW-PASS FILTER ...................... 11 14. POWER TRANSISTOR REPLACEMENT ......... 37 I
TONE AMP. CIRCUIT .................... 12 151TRANSISTOR TYPES ...................... 38 I
EQUALIZER ........................... 12 16. TROUBLE SHOOTING GUIDE ............ 39 ~ 43 I
MAIN AMPLIFIER SECTION. . . . . . . . . , . I 13 ~ 14 17, DIODE TYPES ........................... 44
PROTECTION CIRCUIT (RELAY CIRCUIT) 14~ 15 18.WIRE CLIP .............................. 44
POWER SUPPLY CIRCUIT ................. 16 19. PARTS LIST ......................... 45 ~ 52

SHARP CORPORATION OSAKA, JAPAN

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SPECIFICATIONS

.GENERAL DESCRIPTION

Power source: AC 110/220/240V, 50/60Hz

Circuit

Tuner: Superheterodyne system,

LW/MW/FM 3-bands tuner, with
_ P.L.L. stereo demodulation circuit.
'FM muting circuit, air check
calibration circuit:
Differential amplifier and all stage
direct coupled pure complimentary
0.C.L. (Output Capacitor-Less) cir»
cuitry.
NF type tone control circuit.

Main amplifier:

Tone amplifier:

Equalizer: Two~stage direct coupled equalizer

circuit

Semiconductors: 6-IC (Integrated circuit)
42-transistor (7-FET)
40-diode (4»Zener diode)
2-LED

Dimensions: Width ..... 550 mm
Height ..... 142 mm
Depth ..... 390 mm

Weight: 16 kg

0 FM SECTION

Tuning range: 87.6 ~ 108 MHZ

Intermediate
frequency: 10.7 MHz
Sensitivity: 1.4MV (at S/N 26 dB, 40 kHz

deviation, antenna terminal voltage)
Distortion (40 kHz deviation)
Mono: 0.5%
Stereo: 0.8%
Image rejection ratio: 71 dB
I:F. rejection ratio: 76 dB
Spurious frequency
rejection ratio: 80 dB
AM suppression ratio: 45 dB (modulated by 30% AM
and 75 kHz deviation FM)

Selectivity: 64 dB (IHF)
Capture ratio: 2 dB

Stereo separation: ' 34 dB (1 kHz)
Antenna input: 75 ohms unbalanced

240 ohms balanced

0AM SECTION
Tuning range: MW 520 N 1620 kHz

LW 150 ~ 370 kHz

Intermediate
frequency: MW/LW 455 kHz

Quieting Sensitivity: MW 400;.LV/m (at 1000 kHz)
LW 400uV/m (at 220 kHz)

Image rejection ratio: MW 34 dB (at 1400 kHz)

LW 30 dB (at 340 kHz)

MW 49 dB (at 600 kHz)

LW 40 dB (at 340 kHz)

LW/MW 1.6%

Built-in ferrite bar antenna and

external antenna terminal

I.F. rejection ratio:

Distortion:
Antenna:

.MAIN (POWER) AMPLIFIER
Continuous power output:
2 x 65W/4ohms, both channels
driven at 1 kHz, 0.1% distortion
2 x 40W/8-ohrns, both channels
driven at 1 kHz, 0.1% distortion
Total harmonic distortion:
0.05% at 40W (AUX IN)
Intermodulation distortion:
0.1% at 40W (AUX IN)
More than 20 (at 1 kHz, 4-ohms)
10 Hz ~ 20 kHz

Damping factor:
Power bandwidth:

0 PRE-AMPLIFIER
lnput sensitivity and input impedance

PHONO 1: 2.5 mV/SOK ohms

PHONO 2: 2:5 mV/SOK ohms

AUX: 150 rnV/SOK ohms

TAPE playback

1 and 2: 150 mV/50K ohms

Output level and loaded impedance

REC 1 and 2: 150 mV/SOK ohms

REC 1 and 2 (DIN socket):

30 mV/80K ohms
Phono overload: 220 mV (R.M,S. 1 kHz,
0.1% T.H.D.)

RIAA curve deviation (Phono):
: 0.5 dB
Frequency response: 10 Hz ~ 50 kHz I 1.5 dB (AUX.,
TAPE playback)
Tone control

Bass: I 10 dB at 100 Hz

Treble: 1 10 dB at 10 kHz
Low cut filter: 30 Hz, 6 dB/oct
Audio muting: - 20 dB

FEATURES

1) The power supply circuits for right channel and left channel
are independent from each other, and either of them
includes two dual-capacitors. each of 6800MF x 2 (thus
amounting to 27200pF: 68OOIJF x4 in total).

2) Being composed of FETs (Field Effect Transistors) as
a whole, the equalizer circuit further improves signal-to-
noise ratio.

3) With a built-in protection circuit, the loudspeaker remains
always safe even if the amplifier circuit gets in trouble
and reversely the amplifier is protected against a possible
short-circuit of the loudspeaker cord.

4) Power source/circuit protection indicator making use of
2-color LED element, which will light up in red if there
is something abnormal in the internal circuitry. In a normal
condition, it is lit green.

5) Because of the circuit being ITL (Input Transformerless),
OTL (Output Transformerless), OCL (Output Capacitor-
less) and pure»comp1ementary system, low~distortion
characteristic is more assured.

6) Dual gate MOS FET and 4-gang variablé capacitor adopted
at the FM front-end circuit more improve overall characte-
ristics.

7) The PLL (Phase Locked Loop) demodulator circuit assures
a stabilized characteristic.