Akai AC-R24-MPU Service Manual

PLL SYNTHESIZER STEREO RADIO WITH

COMPACT DISC PLAYER DIGITAL

BND

OPEN

Push SEL

REG

AF TA PTY

REC

DIR

PAU

SCN

RPT

SHF

ENT/LOU

MOD

D-AUD

AMS

MODEL: ACR-24MPU

POWER

DSP

CONTENTS

Page

Disassembly Instructions....................................................................................................................................... 3

Disassembly Diagram............................................................................................................................................ 4

Operation Check.................................................................................................................................................... 5

Block Diagram ....................................................................................................................................................... 6

Alignment Locations .............................................................................................................................................. 7

Alignment Procedures ........................................................................................................................................... 8

Printed Circuit Boards............................................................................................................................................ 9

Exploded Views (Panel) ...................................................................................................................................... 17

Exploded View Parts Lists (Panel) ...................................................................................................................... 18

Exploded Views (Cabinet) ................................................................................................................................... 19

Exploded View Parts Lists (Cabinet) ................................................................................................................... 20

Exploded Views (Deck) ....................................................................................................................................... 22

Exploded View Parts Lists (Deck) ....................................................................................................................... 23

Schematic Diagram ............................................................................................................................................. 25

Electrical Parts List .............................................................................................................................................. 29

Specifications....................................................................................................................................................... 36

DISASSEMBLY INSTRUCTIONS

1. Using the unlock key that came with the unit or a similar tool, unlock the Mounting Box and remove toward

the rear of the unit.

2. Remove two screws (A) located on the rear of the top cabinet then remove the Top Cabinet.

3. Remove two screws (B) located on the rear of the bottom cabinet then remove the Bottom Cabinet.

4. Take out the Front Panel and the Ring.

Remove the screws (C) from on the front side of the Base.

5. Remove two screws (D) from on the right side of the side bracket.

Remove two screws (E) from on the left side of the side bracket.

6. Remove two screws (F) from under the deck front bracket then remove the Deck Front Bracket.

Remove two screws (G) from under the deck rear bracket then remove the Deck Rear Bracket and the

Deck.

7. Remove the screw (H) from on the right side of the side bracket then remove the IC Bracket.

8. Remove two screws (I) from on the left side of the heat sink then remove the Spring Sheet.

9. Remove three screws (J) from on the left side of the heat sink then remove the Heat Sink.

10. Remove the screw (K) from on the back of the side bracket and remove two screws (L) from on the main

board then remove the Heat Sink (7809/DB435).

10. Remove two screws (M) from on the back of the side bracket then remove Wire Clip.

11. Remove two screws (N) from each side of the base then remove the Base.

12. Remove three screws (O) from under the main board then remove the Side Bracket and the Main Board.

DISASSEMBLY DIAGRAM

OPERATION CHECK

GENERAL SPECIFICATIONS OF SIGNAL

Standard frequency

Signal output

Modulation

FM Stereo

AF output level FM/MW/LW

Power source voltage DC 14.0V (Backup voltage is the same as this)

AF load impedance 4 ohm pure resistance

Balance Center position of level

Tone Center position

The signal strength read in this section is voltage on the antenna.

Test Diagram

2-SPEAKER

FRONT SPK.

4-SPEAKER

RL. SPR.

FL. SPK.

4-SPEAKER

98.1 MHz (87.5, 108 MHz)

1000 kHz (522, 1620 kHz)

200 kHz (144, 288 kHz)

1mV

5 mV

400 Hz 30% MOD.

1 kHz 75kHz DEV.

46% for L only or

R only pilot level 8%

RR. SPK.

FR. SPE.

2-SPEAKER

FRONT SPK.

ACC (DV14.4V)

BACK UP (14.4V)

GROUND

POWER ANTANNA

MAIN UNIT

ANT

DISTORTION METER

VTVM

DUMMY ANTANNA

AM SG

FM SG

MPX STEREOS MODULATOR

BLOCK DIAGRAM

FM TUNER BOARD

ALIGNMENT LOCATIONS

ALIGNMENT PROCEDURES

FM ADJUSTMENT

Equipment Required

z AM IF/RF signal generator

z Solid-state voltmeter (SSVM)

z Regulated DC power supply

z 2-CH voltmeter

z Distortion meter

FM Alignment Using FM Signal Generator

Note: Press the radio power switch to on the radio. Signal generator output must be kept as low as possible

to avoid overload and clipping.

Step Generator

Coupling

Stereo

Separation

FM SNC

Adjustment

Stop

Sens.

Note: The tuner module is well-adjust and adjustment is not recommended.

Signal

Generator

to antenna

receptacle

98.1 MHz

Dev. 75 kHz

L+R=90 %

Int. 1 kHz

60dBµV output

Signal Generator

to antenna

receptacle

Generator Display

98.1 MHz

Int. 1 kHz

Dev. 75 kHz

L+R = 90 %

pilot = 10 %

98.1 MHz

@ 40 dBµ

98.1 MHz

Mod. 1kHz

Dev 75kHz

98.1 MHz VR1

98.1 MHz VR2

98.1 MHz

Setting

Adjustment Remarks

Adjust AF

output power

at maximum

separating

more than 30 dB

Stereo Separation

25 dB (±5 dB)

VR3

Adjust AF to

stop station.

MAIN BOARD

PRINTED CIRCUIT BOARDS

TOP VIEW

MAIN BOARD

BOTTOM VIEW

KEY BOARD

TOP VIEW

+ 25 hidden pages