How To Repair No Power And No Sound In Active Speaker
The complaint of this local brand active speaker was no power and no sound. The problem is this active speaker was repaired by someone before thus there is no guarantee that it can be repaired. No matter how I still need to open the set and try to fix it. Below is the photo of the internal section of the active speaker once the cover was removed.
Look at the bad job that was done previously.
The previous repairer did not even clean up the soldered area.
I need to do the cleaning before I start to work on the board. This would be easy to see if there is anymore defect in the circuit board before I further test the active speaker with power On.
I saw couple of dry joints after cleaning the circuit board. I added fresh solder and powered up the set. The power came back but not the sound.
I began to test on the voltages at the connector. There were positive and negative marked beside the connector.
From experience, these DC voltages suppose to be 12 volt.
I found the negative 12 volt present but not the positive 12 volt. See the two photos below:
Since there was no positive 12 volt, I started to check backward (along the 12 volt circuit line) and found a transistor and a 12 volt zener diode shorted.
I replaced both components and the positive 12 volt came back.
I plugged in an USB drive and immediately I could hear the music was playing.
Conclusion- For your information not every time a device that had been repaired by someone can be saved. Sometimes, the repaired was so bad till I need to give up and send it back to the customer. I believe as a repairer, you have encountered it yourself. In the above case, the repairer did not touch on many section thus I’m able to repair it. Ok, will see you again in the next repair article.
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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https://jestineyong.com/no-power-in-singer-lcd-tv-repaired/
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Parasuraman S
June 5, 2020 at 9:51 am
Yes, it is very annoying to see a tampered set by unprofessional service technicians who are keen only in making quick money! Good job there! Many thanks for sharing!
James kamau
June 20, 2021 at 5:30 pm
It is wonderful and helpful I wish to learn more from u
Don Oser
June 5, 2020 at 10:46 am
Great job! One could make the assumption that the previous repairer was not experienced.
Albert van Bemmelen
June 5, 2020 at 12:43 pm
We -trained repairs engineers-, do what we can after someone before us did what he couldn't, failed and made it worse! Thanks for sharing.
Thilak
June 5, 2020 at 1:24 pm
Hi suranga I am from Galle, your every repair article is very informative and I gained lot knowledge. Thank you very much.
Hector De La Torre
June 5, 2020 at 9:09 pm
Good job, I like the way you explain the procedure you take to troubleshoot, plus I also like the pictures.
Ranjit Fernando
June 6, 2020 at 4:47 pm
Suranga you are doing a good service to all hobbyists. Also this repair job was a great help to the person concern.
Steve
June 6, 2020 at 9:55 pm
Hi suranga I am from Lebanon, PA USA. Always love your repairs - always have great pictures from beginning to end of repair.
pa l
June 8, 2020 at 2:42 am
Good job, I like to see these repair videos
Humberto
June 11, 2020 at 6:46 am
Good repair Suranga.
Sadik
July 16, 2023 at 6:04 am
Thank You