akira MMS-02-21 User manual

Multi-Media Speaker
Service Manual

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Model No.: MMS-02-21
Version: 1.0
MODEL:
MMS-02-21

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Model No.: MMS-02-21
Version: 1.0
CONTENTS
SCHEME ANALYSE PANE DIAGRAM................................................................................................ 4
CIRCUIT MALFUNCTION REPAIR ..................................................................................................... 5
CIRCUIT DIAGRAM.............................................................................................................................. 6
EXPLODED VIEW.................................................................................................................................. 8

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Model No.: MMS-02-21
Version: 1.0
SCHEME ANALYSE PANE DIAGRAM

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Model No.: MMS-02-21
Version: 1.0
CIRCUIT MALFUNCTION REPAIR
First segment circuit diagram analyse
Circuit diagram composement
1. OP AMP
OP AMP mainly compose by RW1 (general volume adjust POT) RW2 (tweeter adjust POT),
N1A, N1B (LM4558 OP AMP) and RW3 (woofer control POT) etc, its main function is
control the voice source volume, tweeter and woofer adjustment.
2. Amplifier
It mainly compose by N2, N3, N4 (TDA2030-AMP IC) SP1 S2 SP3 etc, it amplifies the
audio frequency signal and then pass the tweeter and woofer for transform from the electric
sound to original voice.
3. Power Supply
It mainly compose by DL1, C15, C16, C20, C17 (3300uF/ 25V) etc, and provide the steady
power for the whole unit. Second segment typical malfunction analyse and repair solutions.
Typical malfunction repair
1. Output has DC
Malfunction phenomenon: After collected with power, no signal input, some channel have
“buzz” noise.
Malfunction analyse: It has “buzz” noise proves that the channel OP AMP has DC which
leads to the malfunction.
Repair way: Use multimeter to test TDA2030 (1) (2) (4) pin, it should has some DC power
output (one pin or all 3 pins), replace it with a new one and solved the problem.
2. All outputs have big noise (or big distortion)
Malfunction phenomenon: When play it has big “chirp” among the sound.
Malfunction analyse: Usually its because of ripple is too big (normally it happens when unit
uses long time.
Malfunction repair way: Turn the volume to loud, (When it has voice source input and
output, its purpose is make the power have some extent of load). Use the multimeter to test
+15V or 15V and one power lower should be quite big. Then make use the probe to visit this
power, it can be found the ripple is big, if its positive, then retest C15, C20 (3300uF/25V)
CPC, we can test it by replace a good one for checking it. If it negative test C16, C17 in the
same way and the problem can be solved.

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Model No.: MMS-02-21
Version: 1.0
CIRCUIT DIAGRAM

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Model No.: MMS-02-21
Version: 1.0

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Model No.: MMS-02-21
Version: 1.0
EXPLODED VIEW