TV/VCR/Stereo Troubleshooting/speaker


My floorspeader sound ok , however the cone no longer moving , does this affect the quality of sound and how can I fix that .

ANSWER: If cone is not moving (visually) there are several causes to check out.

ONE; the cone has open voice coil.  Can be tested with ohm meter or other methods if you are DIY person.

TWO:  Amplifier feeding that speaker driver is not functioning.

THREE:  The wire between amp and speaker is open; needs connected.

FOUR: Music program material has not music signal at those frequencies (subwoofer, especially).

Tell me more but I need the model number for the speaker and more about your system.


---------- FOLLOW-UP ----------

QUESTION: Thanks , the speaker is Technics SB-CD520 , and the amp is Yamaha RX-V375 .
Mig .

ANSWER: The speakers from Technics are 3-way systems.  They have a crossover network inside which allows separation of the frequency spectrum being sent to the respective speaker.  The power rating of the speakers is around 75 watts.

The Yamaha receiver is rated at 100 watts each channel.

Therefore, if you have been driving the speakers to a loud level over a period of time it is a good possibility the voice coil(s) of the bass driver unit in either or both speakers has gone bad.  I suspect this may be the case.

The repair consists of replacing the voice coil.  A good speaker repair shop can do that job for not a lot of money.  Or, Panasonic may have replacement parts available whereby you might just replace the bass unit.  Cost is usually inordinately high price, however, for single speaker units.

If you are good at basic electronics you can pull the bass unit out of the box (the unit that you claim is no longer moving with the sound) and test it for open voice coil.  This is easy to do if you know how to remove the speaker unit; disconnect the wires to it and measure the resistance across the terminals of the speaker.  You can buy a low cost VOM (volt ohm meter) at such places as Walmart, Home Depot or Harbor Tool (they have one for around $5USD).

Let me know if you need more help.

---------- FOLLOW-UP ----------

QUESTION: Thanks, I have opened the bottom driver ( the biggest ) and test it was 6 ohm Mig .

If the coil measures 6 ohms it means the voice coil is in tact and working okey.  Then you must find if there is an interruption between the amplifier and the speaker such as a bad speaker wire, loose terminal or some other malfunction.

Are both channels the same; that is the bass speaker unit is not moving in both left and right speaker?

And, the music you are playing has some bass sounds?

Check out the overall performance of the system and see if you can determine what is causing the loss of bass sounds.  

TV/VCR/Stereo Troubleshooting

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Consumer Electronics of all kinds. Audio, esoteric audio systems and components, video, tv. Digital equipment for consumer use. Ham radio and automotive electronics. Note: I give advice on tv repair based on general consumer electronics engineering experience but I am not engaged in actual repair of sets. MAKE SURE YOU GIVE THE MAKE AND MODEL NUMBER AND AGE OF THE SET. BE SURE TO CHECK YOUR EMAIL FOR THE RETURN ANSWER DURING THE NEXT 24 HOURS AS I TRY TO REPLY TO ALL QUESTIONS WITHIN THE SAME DAY IF NOT THE SAME HOUR.


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