Akai AC-R224-MMU Service Manual

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 Rear-right Cabinet.

Remove the screw (E) from on the left side of the Rear-right Cabinet and the screw (F) on the right side of

the heat sink.

6. Remove two screws (G) from on the back of the Rear-right bracket then remove the ISO Antenna

Socket/Short W/Holder.

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

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

8. Remove two screws (J) from on the left side of the heat sink.

9. Remove two screws (K) from on the left side of the heat sink then remove the IC Bracket.

10. Remove two screws (L) from on the rear side of Rear-right Cabinet then remove the Power IC Bracket.

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

12. Remove the screw (N) from right side of the Rear-right bracket then remove the Hexagon Nut..

13. Remove the screw (O) from on the back of the Rear-right then remove ISO 36PIN Socket.

14. Remove three screws (P) from under the main board then remove the Heat Sink, Rear-right Bracket and the

Main Board.

DISASSEMBLY DIAGRAM

OPERATION CHECK

GENERAL SPECIFICATIONS OF SIGNAL

Standard frequency

Signal output

Modulation

FM Stereo

98.1 MHz (65.0, 74.0MHz) (87.5, 108.0 MHz)

1000 kHz (522, 1620 kHz)

1mV

5mV

400 Hz 30% MOD.

1 kHz 75kHz DEV.

46% for L only or

R only pilot level 8%

AF output level FM/MW

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

RR. SPK.

FR. SPE.

2-SPEAKER

FRONT SPK.

ACC (DV14.4V)

BACK UP (14.4V)

GROUND

DISTORTION METER

VTVM

DUMMY ANTANNA

AM SG

MAIN UNIT

FM SG

POWER ANTANNA

ANT

MPX STEREOS MODULATOR

BLOCK DIAGRAM

MITSUMI BOARD

ALIGNMENT LOCATIONS

ALIGNMENT PROCEDURES

FM ADJUSTMENT

Equipment Required

AM IF/RF signal generator

Solid-state voltmeter (SSVM)

Regulated DC power supply

2-CH voltmeter

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

Setting

98.1 MHz

Int. 1 kHz

Dev. 75 kHz

L+R=90%

Pilot = 10 %

98.1 MHz

@40dBμ

98.1 MHz

Mod. 1kHz

Dev 75kHz

98.1 MHz VR1

98.1 MHz VR2 Stereo Separation

98.1 MHz VR3

Adjustment Remarks

Adjust AF

output power

at maximum

separating

more than 30 dB

25 dB (±5 dB)

Adjust AF to

stop station.

MAIN BOARD

PRINTED CIRCUIT BOARDS

TOP VIEW

MAIN BOARD

BOTTOM VIEW

KEY BOARD

TOP VIEW

KEY BOARD

BOTTOM VIEW

CD SERVO BOARD

TOP VIEW

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