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Car Speaker fault

Discussion in 'Car Repairs / Maintenance' started by 79diz, 21 Jul 2010.

  1. 79diz

    79diz

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    Hi

    I have a 1999 Ford fiesta zetec- Only have speakers in the front, tweeters and mid range. Recently after a while when playing my stereo the speakers on the right door start to make a high pitch crackling sound. I thought it was the small teeter in the door handle, so disconnected this thinking problem solved. Since then the noise now comes over to the left side after a while so im starting to think maybe its not the speakers and a possible connection fault?

    Thanks in advance
     
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  3. gregers

    gregers

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    check the wires with they route through the car to the door?
     
  4. gman76

    gman76

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    Hello there,

    Could you provide some further info? Does this happen with FM or CD (or both)? does the pitch of the noise increase/decrease with the engine revs?

    I'm guessing the noise is eminating from the stereo itself & disconnecting the HF unit appeared to help as the mid/bass frequency will be rolled off below the freq of the noise.

    Sometimes stereo digital to analogue converters tend to fail on one channel before the other joins in as normal operating temperature is reached.

    If it's doing it on FM though, that will pee over my DAC theory (unless it's a DAB tuner).
     
  5. Mickymoody

    Mickymoody

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    Sounds like the output transistor inside the radio has bust, due to a short, or overloading. Bang in a cheapo '80's radio to confirm/deny, then reattach the speaker, to see if its short.
     
  6. 79diz

    79diz

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    I think its usually ok for 30-40mins then this noise comes along I listen to am more. When it happens I go to FM then after a while it starts here it also does it on CD too. So it seems it could be in the radio itself but wouldnt the output transistor just stop, or is it a gradual thing that gets worse?

    Is it fixable or a new stereo for me?

    Thanks
     
  7. Mickymoody

    Mickymoody

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    No. I've had unbalanced output transistors before, and what you describe is exactly what they do when they break down. They work OK, but one is faulty, either due to overheat, or bad insulation, or a dry joint, then they get out of step and basically have that feedback, like when you put a mic in front of speakers?

    If you are technical, you can remove the radio partially, and spray them with cooler, or heat them with a hairdryer to accentuate the fault, run the radio at full blast, to load them (a blast with the neighbours!), or see if one is dry jointed...if you touch them with your finger, to see if one is hotter than the other, and therefore faulty, isn't recommended, it's like touching a lightbulb. Testing in circuit is hard, as they break down due to heat. And the price of repair may outweigh the cost of a new radio...

    But again, it might be something else, get a £10 radio from Cash convertors, and a convertor kit for the wiring, or upgrade your tunez!
     
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