Akai QX-3700 Service Manual

MINI HIFI

MICRO COMPONENT SYSTEM

Model:

QX3700

SERVICE MANUAL

www.akai.ru

SERVICE MANUAL

Mini Hi-Fi Micro Component System

Hi-Fi MICRO COMPONENT SYSTEM

STANDBY/ON

LOUDNESS

PHONES

VOLUME

QX-3700QX-3700

QX-3700

QX-3700QX-3700

UP/RDOWN/L

REMOTE

FUNCTION

Contents

I. Safety instructions................................................................................................................. 2

II. Specifications...................................................................................................................... 3

III. Level List of Equipments & Instruments Required for Production.......................................... 6

IV. Block diagram .................................................................................................................... 7

V. Wiring diagram ................................................................................................................... 8

VI. Schematic Diagram ..........................................................................................................9

VII. Component Diagrams..................................................................................................... 10

VIII. Exploded Diagram View and Parts List .......................................................................... 18

This manual is the latest at the time of printing, and does not include the modification which may be made after the printing, by the constant improvement of product.

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I. Safety instructions

When using electric products, basic precautions should always be followed, including the following:

1. Read Instructions – All the safety and operating instructions should be read before the appliance is operated.

2. Retain Instructions – The safety and operating instructions should be retained for future reference.

3. Heed Warnings – Adhere to all warnings on the appliance and in the operating instructions.

4. Follow Instructions – All operating and use instructions should be followed.

5. Water and Moisture – The appliance should not be used near water-for example, near a bathtub, wash-bowl, kitchen sink, laundry tub, in a wet basement, or near a swimming pool, etc.

6. Carts and Stands – The appliance should be used only with a cart or stand that is recommended by the manufacturer. An appliance and cart combination should be moved with care. Quick stops, excessive force, and uneven surfaces may cause the appliance and cart combination to overturn.

7. Wall or Ceiling Mounting – The appliance should be mounted to a wall or ceiling only as recommended by the manufacturer.

8. Ventilation – The appliance should be situated so that its lo cation or position does not interfere with its proper ventilation. For example, the appliance should not be situated on a bed, sofa, rug or similar surface that may block the ventilation openings; or placed in a built-in installation, such as a bookcase or cabinet that may impede the flow of air through the ventilation openings.

9. Heat – The appliance should be situated away from heat sources such as radiators, heat registers, stoves, or other ap pliance (including amplifier) which produce heat.

10. Nonuse Periods – The power cord of the appliance should

be unplugged from the outlet when left unused for a long pe riod of time.

11. Power Sources – The appliance should be connected to

a power supply only of the type described in the operating instructions or as marked on the appliance.

12. Power Lines – An outdoor antenna should be located away

from power lines.

13. Power Cord Protection – Power-supply cords should be

routed so that they are not likely to be walked on or pinched by items placed upon or against them, paying particular attention to cords, at plugs, convenience receptacles, and the point where they exit from the appliance.

14. Power requirements for multi voltage (not for all mod

els) – Before connecting the power cord, make sure that the

voltage selector on the rear panel is set to the correct voltage for you area. If not, please set it correctly.

15. Load – For protecting the appliance from being damaged, rated

load while is printed on the appliance or is explained in operation instruction, that should be connected to the speaker output of the appliance. Never short circuit the speaker output of the appliance when the appliance is working.

16. Object and Liquid Entry – Care should be taken so that

objects do not fall and liquids are not spilled into the enclosure through openings.

17. Cleaning – Unplug the appliance from the wall outlet before

cleaning. Do not use liquid cleaners or aerosol cleaner. Use a damp cloth for cleaning.

18. Make your contribution to protect the environment –

Used batteries with the ISO symbol for recycling as well as small accumulators (rechargeable batteries), mini-batteries (cells) and starter batteries should not be thrown into the garbage can. Please leave them at an appropriate depot.

Portable cart warning

19. Overloading – Do not overload wall outlets and extension

cords as this can result in a risk of fire or electric shock.

20. Damage Requiring Service – Unplug this appliance from the wall outlet and refer servicing to qualified service personnel under the following conditions: a). The power-supply cord or the plug has been damaged; b). Objects have been fallen, or liquid has been spilled into

the appliance; c) . The appliance has been exposed to rain; d) . The appliance does not appear to operate normally or ex-

hibits a marked change in performance; e). The appliance has been dropped, or the enclosure dam

aged.

WARNING TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

CAUTION TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE COVER (OR BACK). NO USER SERVICEABLE P ARTS INSIDE. REFER SERVICING T O QUALIFIED SERVICE PERSONNEL.

The lightning flash with arrowhead symbol, within an equilateral triangle, is intended to alert the user to the presence of uninsulated “dangerous voltage” within the product’s enclosure; that may be of sufficient magnitude to constitute a risk of electric shock to persons.

The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the literature accompanying the appliance.

CLASS 1 LASER PRODUCT

This product contains a low power laser device. To ensure continued safety, do not remove any covers or attempt to gain access to the inside of the product. Refer any servicing to qualified personnel.

A. CLASSIFICATION LABEL, PLACED ON EXTERIOR SURFACE

CLASS 1 LASER PRODUCT KLASSE 1 LASER PRODUKT LUOKAN 1 LASER LAITE KLASS 1 LASER AP PARAT

B. WARNING LABEL, PLACED INSIDE THE UNIT

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II. Specifications

CONDITIONS OF SPECIFICATION MEASUREMENTS

1. STANDARDS ENVIRONMENTAL CONDITIONS TEMPERATURE : 23°C HUMIDITY : 65% IF NO DOUBT ARISES IN THE JUDEMENT, THE MEASUREMENT CAN BE MADE UNDER CONDITIONS OF TEMPERATURE 10 TO 35°C AND HUMIDITY 45 TO 85%.

2. REATED POWER SUPPLY AC: 220V 50Hz

3. LOAD IMPEDANCE SPEAKER OUTPUT : RESISTIVE LOAD AS SPECIFIED.(4 OHM) PREAMPLIFIER OUTPUT AND RECORDING OUTPUT : 47k OHM RESISTOR (± 5%) VIDEO OUTPUT: 75 OHM

4. STANDARD OPERATING CONDITION AND METHOD OF MEASUREMENT a) OPERATION METHOD, SETTING POSITION OF THE UNIT STARTING CONDITION

FOR THE MEASUREMENT SHOULD BE MAINTAINED FOR TESTS OF AMPLIFIER SECTION AS EIA-RS-490, FOR TEST OF TUNER SECTION AS IHF-T-200.

b) EXCEPT AS OTHERWISE SPECIFIED HEREIN, ALL TESTS SHALL BE MEASURED AT

FRONT CHANNELS AND SET THE SELECTOR POSITION.

MEASURED MODE

c) MODULATION OF FM DODE 75KHz DEVIATION AUDIO 1KHz 75 OHM d) MODULATION OF FM STEREO MPX. 67.5KHz DEVIATION

7.5KHz PILOT

AUDIO 1 KHz e) MODULATION OF MW 30% MOD. AUDIO 1KHz f) REF. OUTPUT LINE OUT

Specifications

1. FM Section

FM Electrical Specifications (Text Point at Line Out)

Measurement Specifications Measurement Condition/Method/Remarks Description 1HF FM Measu. SSG Others

BPF MODE Freq. Level FM RANGE 87MHz~108MHz 30dB S/N ≤20uV Mono 98MHz Adjust AUTO STOP 30±5dBuV Auto 98MHz Adjust Output level ratio of modulation SENSITIVITY OFF to ON Pilot : ON, R ch :

OUTPUT LEVEL 0.50±0.1Vrms Yes Mono 98MHz 60dBu Measure both channel test

point at Line Out STEREO ≥20dB Yes Auto 98MHz 60dBu SEPARATION

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2. MW Section

i. MW Measurement Condition

(a) Antenna Input : Loop Antenna (b) Measurement Frequency : Lower Center Upper

All versoin 603kHz 1008kHz 1404kHz (In case of no comment, measure at

center frequency.) (c) Modulation Frequency : In case of no comment, use 1kHz 30% modulation (e) Selectivity : Arithmetical mean of 2 values at ±10kHz deviated frequency (f) Measurement Point : Test Point (At line out)

ii. MW Electrical Specifications

Measurement Specifications Measurement Condition/Method/Remarks Description Meas.Freq. SG Level Others AM RANGE 522KHz~1611KHz 26dB S/N ≤5.0mV/M Center Adjust Output level ratio of

modulation OFF to ON AUTO STOP 20mV/M Center Adjust Minimum input level of Auto Stop SENSITIVITY ≤Auto Stop Sensitivity threshold

≤5.0mV/M

OUTPUT LEVEL 150-500MVrms Center 10mV/M Measure both channel test point

at Line Out

3. VCD Section

VCD Measurement Condition Measurement Point: At line out or video out

1. Electrical Specifications

No. Test Item Unit Specification 1 Video Output Level Vp-p 1.0±0.2 2 Audio Output Level Vrms 2.0+0.2/-1.0 3 Audio of Resp (20Hz~20KHz) dB ≤±3.5 4 Audio S/N (A-WTD) dB ≥70 5 Distortion & Noise (1KHz) dB ≤-50 6 Cross Talk L-R (Fundamental) dB ≥60

2. Mechanical Specifications

No. Test Item Unit Specification 1 Reading Time S <20 (S) 2 Ball Bound:

Drop 8g Super Ball from 3cm Height No AV Noise

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4. AMPLIFIER Section

i. AMPLIFIER Measurement Condition (a) Power Output : Measure without pre-heating (b) Source Impedance : Normally 600 (c) S/N : Measure the noise level without low frequency ( 80Hz) vibration (d) Frequency Response : Measure at -10dBs output (1kHz) by adjusting oscillator output (e) Difference of L/R ch : The output level difference between L ch and R ch at ± 3dB output (f) Other : In case of no comment, set volume maximum and 4 load

ii. AMPLIFIER Specifications

Measurement Specifications Measurement Condition/Method/Remarks Measurement Description Test Input Input Signal Output Vol. Method/Remarks

Point Selector Freq. Level Level

Power Output 15±3W SP out Line 1kHz Adjust Adjust MAX Both channel drive/

front THD 2% 4 load

Distortion Less than 2% SP out Line 1kHz Adjust 12W MAX Both channel drive/

load read best

4 value when indicator of distortion meter is

changing Line Input 200±50mV SP out Line 1kHz Adjust Adjust MAX Sensitivity THD 2% S/N ≥65dB SP out Line 4.7k

Terminate Channel more than 30dB SP out Line 1kHz Adjust 5W MAX Measure a ratio of Separation leak level of L

Frequency ±2dB SP out Line 80Hz Adjust +3dBs MAX Measure the level Response 12.5kHz difference Loudness +10dB±5dB H:10KHz Line 1KHz Adjust --- 30Bar Difference from 1KHz

L:100Hz out Line Out 80±20mV Line out Line 1KHz Adjust Adjust MAX Level THD 2%

5W MAX

L; Measured

R channel input terminal AUX: 4.7k Terminate

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Measurement Specifications Measurement Condition/Method/Remarks Measurement Description Test Input Input Signal Output Vol. Method/Remarks

Point Selector Freq. Level Level Frequency - 5.0 dB ± 3.0dB SP AUX 10Hz Adjust 0dBs MAX Measure the level Response - 4.0 dB ± 3.0dB OUT

Super Bass + 10dB ± 3.0dB SP AUX 70Hz Adjust 0dBs 30 Measure the level

OUT difference ( S BASS

Loudness Low + 6.0 dB ± 3.0dB SP AUX Equalizer - 10.0 dB ± 3.0dB OUT Position

High + 5.0 dB ± 3.0dB 10kHz

- 7.0 dB ± 3.0dB

100kHz difference from 1kHz

output

ON)-(S BASS OFF) at 1kHz Volume Level 30 Position

100Hz Adjust 0dBs 30 Volume Level 30

III. Level List of Equipments & Instruments Required for Production

NO. Designation Requirement Reference Model Remark

1 Standard signal EXT. MOD. Input LEADER 3216 1 set

Generator Modulation: AM 0-60%

FM 0-99.9KHz Frequency: 0.1-140MHz Level: -20-120dBu Output: 1-50W

2 AC voltmeter Inter Resistance 1M-10MW KENWOOD V7-171 2 set

3 Automatic VP7702C 1 set

Distortion Meter

4 CD Player NF3346A 1 set

Evaluation Filter

5 Multiplex Signal KIKU SUI 3400S 1 set

Generator

6 Oscilloscope Max Frequency of input signal; KENWOOD CO-1305 2 set

5MHz

7 Oscillator Frequency of output signal; KENWOOD AG-203A 2 set

20Hz-20kHz

8 Test Loop Resistance: 50 LEADER LPA-070 1 set

Frequency: 100KHz~30MHz

9 WOW FLUTTER MEGURO 1 set

METER MK-668G

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IV. Block diagram

AUX

AUDIO OUT

LINE1 OUT

VOL VOL

SYSTEM CONNECTION

MASTER

SYSTEM CONNECTION

LINE2 OUT

PT2314

25100-3A08

MUTE

STAN

VFD

JRC4558A

+22V

-22V

LM1876A

MUTE

+5V

REM

LEVEL

DATA

VOL VOL

78E54

DO DI CLK

STB

SW TU

PT16311

JRC4558B

FUCTION

STAND

LOUD

LM1876B

STAN

PHONES

LCH

VIDEO OUT

FMAM

LGR

TUNER T-933-2

+12V

VCD MEPEG DECODER

STB

CLKDGREM

CE CLK DI DO

+5V

+8V

AC17V

0V AC3V5 AC3V5

AC220V

T4A

AC220V

-21V

0V F2 F1

AC17V

AC17V AC10V AC10V

AC12V

7805

+22V

-22V

D5V

DGND

TO CPU

7812

2N5401

7805 TO VCD

7808

TO VCD

RCH

+12V

-12V

D5V

TUNCEDIDOCLK

AC220V IN

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+ 19 hidden pages