How To Repair Active Speaker- Matsutec Brand
The complaint of this Matsutec active speaker was no sound but have power.
The right channel produced 32 VDC even though the volume is already in minimum position which means something has shorted inside especially the semiconductor components. The left channel was good. See the photo below:
Once the cover was removed, I saw a burnt resistor in the circuit board. So whenever a resistor is burnt there will be something shorted that had caused the resistor to burn.
Next I checked all the corresponding/nearby components and found three transistors were actually shorted. All other parts were tested good.
The shorted transistor part numbers were B688, D718 and D667-see the photo below:
I bought the parts from local market and fitted in and powered On. Both channels the sound came back and I was very happy with it.
Conclusion- If you found any burnt resistor, always check along the resistors line to look for shorted components especially the semiconductors. It can be shorted transistors, diodes, zener diodes, capacitors and etc. You can check my previous article about Matsutec active speaker with no sound/no power symptom below:
https://jestineyong.com/matsutec-active-speaker-system-repaired/
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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Note: You may check out his previous repair article in the below link:
https://jestineyong.com/led-tv-repair-cheap-replacement-parts/
Albert van Bemmelen
July 4, 2016 at 3:37 pm
Thanks and good job Suranga. The client can be happy his Loudspeakers are still intact. At home I have a 400 Watt Yamaha AX400 Amplifier and it blew my Westra kw-160-1334 4 Ohm Bass LoudSpeaker. You can't buy them anymore since they stopped producing them. So I had to replace them by more Middletoner Visaton 17E 4 Ohm Loudspeakers. So my original Elac Boxes sound a little different now. (Less Bass since Visaton goes up to 7000 Hz compared to the better sounding Westra Loudspeakers that only go to 4000 Hz. That is why I am selling my one good left rare original Westra Bass Loudspeaker on Ebay now).
Parasuraman S
July 4, 2016 at 3:40 pm
Good job! Thanks for sharing!
Mr. Soft
July 4, 2016 at 6:11 pm
Good job man, I always enjoyed your post. its indeed helpful. more grease to your elbow.
Robert Calk
July 5, 2016 at 11:37 am
Good job, Suranga.
Anthony
July 5, 2016 at 12:48 pm
Good fast repair Suranga ! Well done !
biruk aweke
July 5, 2016 at 1:01 pm
very nice explanation.