akira MMS-251 User manual

Multi-Media Speaker
Service Manual

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Model No.: MMS-251.doc
Version: 1.0
MODEL:
MMS-251

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Model No.: MMS-251.doc
Version: 1.0
CONTENTS
IMPORTANT SAFETY MEASURES .....................................................................................................4
CHARACTERISTICS..............................................................................................................................5
REMOTE CONTROL DESCIPTIONS....................................................................................................6
PANEL/REAR DESCRIPTION...............................................................................................................7
BASIC OPERATION...............................................................................................................................8
SYSTEM CONNECTION PICTURE......................................................................................................9
SPECIFICATION...................................................................................................................................10
HOW TO REPAIR SPEAKER MALFUNCTION................................................................................. 11
EXPLODED VIEW................................................................................................................................12
PART LIST.............................................................................................................................................13
CIRCUIT DIAGRAM............................................................................................................................14

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Model No.: MMS-251.doc
Version: 1.0
IMPORTANT SAFETY MEASURES
Before using this machine, please read all the safety and operating instructions, meanwhile, please
observe all the indications about safe operating. These safety and operating instructions should be kept
in condition consultation.
1. Protection electric power supply lines: Be aware that the electric power supply is not
tramped, pressed by heavy objects. Pay special attention to the plug of power supply line and
the outlet on the machine. DO NOT lengthen the electric shock. DO NOT pull or drag or the
power supply line.
2. Ventilation: this set must be put in ventilated place. DO NOT push disk on it or cloth to
cover it. The distance away from the wall should not be less than 10 centimeters. DO NOT
put this set on the bed, sofa, carpet or other objects with similar surface in case of good
ventilation.
3. Casing dismantling: do not dismantle the casing. If the one touches the inner components,
he will probably get serious electric shock.
4. Unusual smell: when you discover unusual smell and smoke, shut off power supply
immediately and pull out the plug from the outlet from the wall. Contact the sell shop or
nearest repairing center.
5. Attention: this set applies to 220V∼240V 50/60Hz power supply. Use Standard power
supply and do not use power supply of small output to adjust and steady voltage.

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Model No.: MMS-251.doc
Version: 1.0
CHARACTERISTICS
•5.1 channel independent channel adjustment for a home theatre effect.
•With remote control, 7 color LCD display. Novelty outlook design.
•High quality make and finishing.

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Model No.: MMS-251.doc
Version: 1.0
ROMOTE CONTROL DESCRIPTIONS
1. Standby
2. Definite direction logic
3. AUX key
4. Main volume +/- control
5. Mute
6. Common stereo
7. Center +/- adjustment
8. Surround +/- adjustment
9. Subwoofer +/- adjustment
10.5.1 CH key
OPERATION RANGE OF THE REMOTE CONTROL
Infrared sensor
NOTICE: there should be big obstacle between the remote control and the main unit.

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Model No.: MMS-251.doc
Version: 1.0
PANEL/REAR DESCIPTIONS
Front panel functions
1. Standby
2. Remote receiver
3. Instruction light of standby
4. Instruction light of main mute
5. Instruction light of AUX
6. Instruction light of 5.1 CH
7. Instruction light of prologic II
8. Signal input selection
9. Normal/prologic II
10. Main volume control +/- key
Rear panel function:
11. AUX left/right input
AC-3 input:
12. Front left/right input
13. Rear surround left/right input
14. Center input
15. Bass input
16. Speaker output:
•Main channel front right output
•Main channel front left output
•Center output
•Rear surround right output
•Rear surround left output
17. Power switch
18. Power cable

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Model No.: MMS-251.doc
Version: 1.0
BASIC OPERATION
Be sure that the input and output cables are properly connected. Turn on the power switch on rear panel
“On/Off”, now the unit is switched on, and instruction light turn on the front panel, Press “Standby” on
the Panel or remote controller to turn on the Standby mode.
Signal input selection:
Press “Input” on the panel or remote controller, according to the rear panel selection choose signal
sources DVD, AUX input circular selection.
Switching between Normal/Prologic mode:
When “AUX” light is on, press “Prologic II” to change 2.1ch into 5.1ch output status, (when in the
status of 5.1ch input, there will not be response when you press “Prologic II” button. When “Prologic
II” light is on, system status is 5.1ch output).
Main volume control:
Press front panel (or remote control main) “+” or “-“ the volume increase (or decrease), the indicator
light will response accordingly, for example: when increasing the main volume, the indicator light will
extinguished, from PROLOGIC II lighten 5.1CH, AUX, MUTE, STANDBY light, when adjust to the
loudest volume, “STANDBY” light plashed continuously and stopped after 3 seconds.
Press “-“ button, the volume decrease, on the front panel, the indicator lights all lightened, then
gradually extinguished from the STANDBY to MUTE, AUX, 5.1CH, PROLOGIC II, when the volume
decreases to the lowest, PROLOGIC II light flashed and stopped after 3 seconds.
Remark: when retreat from the main volume adjusting function, all corresponding indicator lights
return to the original condition.
Standby
Press one time the “STANDBY” on remote controller into standby mode, press again into working
mode.
Mute operation
When the machine is working, press “MUTE” on the remote controller will effect silence condition,
press again will revert to work condition.
Central volume control
Press “+”, “-“of “CEN” on the remote controller, press “+” to increase the volume while “-“ to reduce
it, indicator light working mode is same as main volume display mode.
Surround volume control
Press “+”, “-“ of
Subwoofer volume control

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Model No.: MMS-251.doc
Version: 1.0
SYSTEM CONNECTION PICTURE

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Model No.: MMS-251.doc
Version: 1.0
SPECIFICATION
ITEM SPECIFICATION
Satellite speaker 12Wx5
Main speaker 30W
Input impedance 10K Ω
Frequency response for Satellite speaker 110Hz – 20KHz
Frequency response for Main speaker 42Hz – 159Hz
Power ∼220V-240V 50/60Hz

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Model No.: MMS-251.doc
Version: 1.0
HOW TO REPAIR SPEAKERS MALFUNCTION
Reason Repair step
No voice Speaker burned, speaker output line broke. Collectors with amplifier is
incorrect.
Low Voice Speaker quality is poor, woofer phase is in opposite position.
Voice distortion Speaker magnetic loop deflection or speaker magnetic iron part
deflection; speaker plate distortion; amplifier power is too large.
Voice noise Speaker plate broke; speaker case gap broke; speaker rear panel loose;
speaker grill loose.
High Frequency poor High frequency crossover capacitor quality is poor; speaker unit is poor;
grill incorrect use.
Low Frequency poor Frequency crossover net is bad low frequency speaker unit is poor.
Echo Voice poor Speaker Location is incorrect; two speaker collector +- is incorrect.

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Model No.: MMS-251.doc
Version: 1.0
EXPLODED VIEW

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Model No.: MMS-251.doc
Version: 1.0
PART LIST
No. Parts name QTY’
1 Port tube 1 PC
2 Control panel 1 PC
3 Transformed 1 PC
4 5YD – F60A– 4 Woofer 1 PC
5 ∅220 Grille 1 PC
6 Amplifier 1 PC
7 BA4X12 Screw 2 PC
8 BA4X12 Screw 10 PC

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Model No.: MMS-251.doc
Version: 1.0
CIRCUIT DIAGRAM