No Sound In Mitashi SubWoofer Repaired
The complaint of this Mitashi Sub Woofer was no sound but have power. As usual, in order to repair the set, one need to open up the cover for visual inspection to see if there is any dry contact, loosen connectors/cables and etc.
The top part seem to be ok so I proceeded to check the dc supply voltage of the pre-amp IC. This means I have to flip the circuit board and power On the set and perform the dc voltage test using my dc voltmeter.
From the test, I noticed that there was zero volt to the pre-amp IC. This is the reason why the sub woofer have power but no sound. Take a look at the meter display below:
When I followed the DC voltage path moving backward I saw the circuit track was actually broken.
I did not stop there, I continued to check the components that are related to the circuit path and hope they are all good. After spending quite a while, indeed there were no bad components around this circuitry.
Next, I soldered a wire to make a joint so that the circuit path can conduct again. It was pretty easy to do this. Just like any soldering work, once done I cleaned the board and applied silicone glue to secure it.
It was a simple and a straight forward repair and did not require any deep thinking. The sound came back when the subwoofer was On.
This article was prepared for you by Suranga Bandara who owns an Electronics shop in Anuradapura, Sri Lanka.
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Note: You may check out his previous repair article in the below link:
https://www.jestineyong.com/display-problem-in-lcd-tv-repaired/
https://www.jestineyong.com/matsutec-active-speaker-system-repaired/
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Yogesh Panchal
September 12, 2015 at 2:30 pm
Suranga ,Congratulations for fix.
Joe
September 13, 2015 at 2:41 am
Hello! Just curious, were you using a schematic on this repair? Great job in finding the problem...
Joe
Chris
September 16, 2015 at 4:09 am
Great job Yogesh, congratulation.
Why was the wiring broken?
Did you figured out that?