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KLH R3000 Stereo Receiver wont turn on.

Discussion in 'Troubleshooting and Repair' started by Rickedafied, Sep 6, 2014.

  1. Rickedafied

    Rickedafied

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    Aug 3, 2014
    One day the stereo didn't want to turn on. I checked for cold solder on the boards and I found nothing. I had the stereo unplugged for about 3 weeks and when I tried turning it on, it worked. After a few days being plugged in, I went to turn it on again and it wouldn't turn on, but after leaving it unplugged again for a while, it did turn on again, but now when I try to select FM, CD, Tape or TV, it keeps going back to VCR by itself. So I removed the front control panel and had a look at the circuit board and found this square component with a crack on it.

    It looks like this would be the reason why it wont let me select anything, but what kind of capacitor is this and how does it work?
    Could this also be the cause of the power button not turning on the stereo?
     

    Attached Files:

  2. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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  3. shrtrnd

    shrtrnd

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    Hopefully it was just the capacitor. When I lose a small innocuous componet like this wthout explanation, I always follow the trace on the board to the connected components, just in case something ahead of the
    cap failed, which resulted in the destruction of the cap. It's pretty common to just lose a capacitor like this, but as long as you've got access to the board, I'd take the time to look carefully at the rest of the board.
    Just my 2 cents worth.
     
    KrisBlueNZ likes this.
  4. Rickedafied

    Rickedafied

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    Aug 3, 2014
    Yeah, im hoping its just that capacitor too. I'm gonna inspect the rest of the board before I install the new one. Thanks guys
     
  5. Rickedafied

    Rickedafied

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    Aug 3, 2014
    Can the super capacitor be replaced with a regular capacitor?or even a non polarized capacitor?
     
  6. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Not if you want the unit to remember its settings during a brief loss of power, for example if you move it to a new power socket. But otherwise, yes.
     
  7. Rickedafied

    Rickedafied

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    Aug 3, 2014
    Ok. Could I use one like this? I'm not sure how these kind work.
     
  8. Rickedafied

    Rickedafied

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    Aug 3, 2014
    DSCN0307.JPG
     
  9. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    You could, but you'd might as well not bother. That's a 47 nF capacitor - one millionth of the capacitance of the supercap. If you're not going to replace the supercap with another supercap, just remove it.
     
  10. Rickedafied

    Rickedafied

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    Aug 3, 2014
    Ok I'm gonna try that and see how it works
     
  11. Rickedafied

    Rickedafied

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    Aug 3, 2014
    I removed the failed super capacitor and powered up the stereo to see if i can select the CD, Tape and FM buttons and so far its working. So I left the stereo plugged in and turned it off, I went back about an hour later to turn it back on and again it doesn't turn on. Usually I would hear the relay switch before it turns on, but I don't hear it. All I see is the little green light on the volume knob.
     
  12. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    OK. Now do you think it might be a good idea to buy a supercapacitor and install it?

    You may want to check the voltage across the supercapacitor position to make sure there's no other fault in the circuitry. If the voltage is greater than 5V that would explain why the original one failed, and it would tell you that you need to fix something before you install a replacement supercap.
     
  13. Rickedafied

    Rickedafied

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    Aug 3, 2014
    Its showing +4.88V
    The stereo was working before I turned it off though. I was able to turn it off and on, over and over, but if I leave it off for a while, it won't turn on again.
     
  14. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Then I would assume the failure of the original supercapacitor was not caused by an external problem, and install a replacement.
     
  15. Rickedafied

    Rickedafied

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    Aug 3, 2014
    I can't find a replacement at the electronic stores. If its just for memory, why doesn't the stereo turn on?
     
  16. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    I don't know. It may not be the only problem. There's one way to find out though.
     
  17. Rickedafied

    Rickedafied

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    Aug 3, 2014
    How?
     
  18. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    By replacing it and seeing what happens!
     
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