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Signal Relay Bad

Discussion in 'DIY' started by NeedForSpeed, Feb 8, 2018.

  1. NeedForSpeed

    NeedForSpeed Living In The Past Subscriber

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    I have a Musical Fidelity Phono Pre amp, And it started a loud clicking. Opened it up, And one corner of the board gets very hot, And feel 2 relays vibrating more than the others. I found the relay on line, But a 20 week wait? There is a Panasonic hat I think is the substitute, But will that change the sound? Thanks in advance
    IMG_0561.PNG
     
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  2. Ray Gianelli

    Ray Gianelli AK Subscriber Subscriber

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    From what you describe it sounds like whatever drives the relay is suspect. A bad relay shouldn't cause heat issues.

    Is the power supply ok? Correct voltages, no ripple? That's where I'd start looking.
     
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  3. avionic

    avionic " Black Knights " Subscriber

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    If the relay works there should be no change in sound quality.
     
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  4. avionic

    avionic " Black Knights " Subscriber

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    Likely a relay driver pass transistor. Or regulated supply pass transistors. Are there heatsink mounted transistors on that corner of the board ?
     
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  5. NeedForSpeed

    NeedForSpeed Living In The Past Subscriber

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    Thanks for reply, I have a pic. I pulled one reply that felt hot. Also, These are stick on, My first time with that style
    IMG_0563.JPG
    The lower left corner got very hot
     
  6. NeedForSpeed

    NeedForSpeed Living In The Past Subscriber

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    I use an external power supply, Pangea P-100. Seems okay
     

     

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  7. avionic

    avionic " Black Knights " Subscriber

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    Oh fun... SMT
     
  8. Ray Gianelli

    Ray Gianelli AK Subscriber Subscriber

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    The external power supply may feed an internal power network, and if it's getting hot in that corner that may be the issue.

    As avionics pointed out SMT is a pain to work with. But it is doable if you have good tools and are careful.

    Check for shorts around where it's getting hot.
     
  9. gadget73

    gadget73 junk junkie Subscriber

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    sounds more like the relay is being fed too much voltage, or its getting AC when it should be getting DC. Either way I'd agree that its probably not the relay so much as whatever controls it.


    Put the power supply on the scope, thats really the only way to tell if it has ripple problems.
     

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