5e3 PT Voltage Issue

Discussion in 'Shock Brother's DIY Amps' started by RPercival, Feb 14, 2019.

  1. RPercival

    RPercival TDPRI Member

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    Understood. I have to think it’s a fault in the transformer but I don’t want to be too quick to condem a new part, and the voltage to the center tap is very strange.
     
  2. rolloman

    rolloman Tele-Holic

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    sure is looking as if the green wires are shorted together internally. I think Lol Very strange issue.
     
  3. RPercival

    RPercival TDPRI Member

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    That was my thought too, but that center tap voltage has me puzzled.
     
  4. rolloman

    rolloman Tele-Holic

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    maybe internally both greens got soldered to the same spot so you have no wire at all on one of the ends of the total coil length. Just a center and two wires from one end or the other together coming out.
     
  5. peteb

    peteb Friend of Leo's

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    The problem with the transformer that would explain what you have is that one half of the winding is reverse wound from what it should be.


    Each side produces a voltage but the two ends are in phase with each other, so no voltage between the two ends.
     
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  6. rolloman

    rolloman Tele-Holic

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    Or somebody got a kick out of 2 greens from the same place. Either way it looks as if a return and replace is in order. To get up and going do you have anything else you could get filament voltage from handy. Ya know most of us crazies have things like that hanging around our shops. Lol
     
  7. RPercival

    RPercival TDPRI Member

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    That’s a good thought there. I don’t really want to open it and void warranty. I’ve completely removed the tranny from the chassis and have the same issue. I think I have to call this one faulty.
     
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  8. RPercival

    RPercival TDPRI Member

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    I do actually. I have a stand alone power supply that I could use, but I also have a stable of amps to keep me busy until I can sort this one out properly.

    I’ll email Dave and see what he thinks. Thanks everyone.
     
  9. jimgchord

    jimgchord Tele-Holic

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    Sounds like a bunk tranny. I got a classictone recently that they had swapped one of the red wires for the center tap .not as bad as your issue, but it does happen
     
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  10. RPercival

    RPercival TDPRI Member

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    Yep, mistakes happen. Not a big deal. Swap it out for a new one (test the crap out of it before installing), and then move on and see what I messed up during the build. Haha.
     
  11. robrob

    robrob Poster Extraordinaire Ad Free Member

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    "I don’t believe trannies can have phase issues since they are a continuous winding, but that’s what it seems like."

    I'm not 100% sure about this, but I believe if you wind "down" to a center tap, then wind back up to where you started you'd end up with two outputs with equal voltage but in phase so 0v between the two leads but voltage between the ends and the center tap.
     
  12. RPercival

    RPercival TDPRI Member

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    That would make sense, but I imagine they’re machine wound so doing one reversed from the other seems hard to happen. I’m guessing that both greens are attached to the same place, but I don’t want to open it up and void warranty.
     
  13. robrob

    robrob Poster Extraordinaire Ad Free Member

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    The two wires could also be shorted together near their exit point giving you the same thing as two wires tapped from the same spot.
     
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  14. hackworth1

    hackworth1 Friend of Leo's Vendor Member

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    I will contact the man at Classic Tone factory and alert him to this post.
     
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  15. peteb

    peteb Friend of Leo's

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    From the symptoms, to me, it would be the lower sketch, one winding reversed which makes it two of the same windings. If the windings were wound right like the upper sketch and the two ends were joined, I don’t think you would get a good measurement like was gotten. I think the two ends would be out of phase and cancel the other out.





    FE97F5EA-35FD-4879-8BE0-A8B07E6CC938.jpeg
     
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