Possible free Hameg O-scope. Are they good for amp work?

Discussion in 'The Squawk Box' started by Marshall & Moonshine, Dec 31, 2017.

  1. Caoimhin

    Caoimhin Senior Member

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    I don't know anything about scopes but I enjoy messing around with tube amps. I'd like to get one some day and I was wondering if there are any cheap brands out there that I could look into? Is there certain type of specs I should be looking or?
     
  2. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    I’ll hit up the Electrician. He’s probably got a few kicking around.
    Or yeah.
    I’m gonna steal one from a computer, and try to have it back before some genius breaks the On/Off button.
     
  3. ehb

    ehb Chief Discombobulator Premium Member

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    Da lectric can set you free.....

    Spent about 45 min on a floor leaning against a concrete wall trying to talk and shit once years ago... Got hit hard.

    A bud EMT kneeling beside me after checking me out...

    "We're you just trying to say sonofabitch?"
    Wuh whuh. Woo mastard... ;)
     
  4. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    Give you a haircut like Buckwheat.
     
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  5. Leña_Costoso

    Leña_Costoso Senior Member

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    That must be "field of endeavor" specific. In my trade, we call all of the earth ground measuring equipment a "megger", no matter who makes it, and we "meg the grounds", to find the earth ground resistance.

    Funny how that works
     
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  6. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    It’s why I’m leery to start working towards being an electrician ashore.
    Everything is different.
    No conduit, all armored cable. No neutral, no wire nuts (welllll......;)), all stranded conductors, on and on and on. Plus, I’d need to learn the business side of things. I’m 43 now, and that’s the kind of things you really should already know, if you’re gonna open your own shop.
    For us, if they say to meg it, you clip one side to ground, the other to the circuit and give it the Voltage. Meter tells the story. Anything under 1M is suspect. I guess “earth” and “ground” are the same things, at least for us. We’re not talking electronics at this point; just power circuits. “Ground” to us is “the steel of the ship” or something with continuity to the hull.
     
  7. Leña_Costoso

    Leña_Costoso Senior Member

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    My first Simpson 260 was bought to get high ohms reading...not exactly "megging" but sort of. We had double insulated, flat pair communication cable. Flat pair being ok, as it communicated at 60 cycles! The system was both current and voltage based, whereby outbound data was voltage based in the form of clipped waves, and return data wasn't really data but sort of acknowledgement, in the form of a dead short for 1/120 second, or half a cycle (or 180 degrees). We needed to have good ground isolation for it to work, and, we needed to have perfect splices, of which there were many in good ol' mother earth. Amazingly that system stayed in use for nearly 35 years, still in use today (and I have no idea why!).
     
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  8. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    It powers up!! Still no leads, but both channels move up and down, and all the buttons seem to do something!!
    Yeah baby!!
    Should I open it up and clean it with some contact cleaner or something?
    Or should I adopt the age-old wisdom of not fcking with something that works? It was coated on the outside with a film of old oil vapors, with a little heavy fuel on the bottom.
    Somebody went well out of their way to not give a shit about this thing. Or they were gonna steal it and forgot it. And the leads. And the power cable. And the manual. And the case.
    Just insane.
    I know Don is a scope guy. What do you think, @Soul Tramp ?
    Did Dumbdumb do good?
    :)
     
  9. Leña_Costoso

    Leña_Costoso Senior Member

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    stick a little wire in the center of the BNC fitting, hold the other end in your fingers. You ought to be able to "dial in" an erratic sort of squishy distorted sine wave. Since you have already tested overall vertical deflection, the only thing to test is the timebase and if it will deflect from input

    Get the best leads you can afford.... they'll likely last a long time
     
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  10. KP11520

    KP11520 Senior Member

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    Blow it out with canned air. DON'T use a vacuum. If anything needs a chemical clean, look for non residue contact cleaner so it cleans and leaves nothing behind. Pots need MG Chemicals Super Contact Cleaner with PPE.

    I can see your inner Uncle Fester shining right now!
     
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  11. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    @Leña_Costoso , would you mind posting a link for some decent leads? I’m looking around and seeing the specs, and I know what they basically mean (capacitance, frequency, attenuation, Voltage rating, etc...), but I don’t know what is desirable for amp work. The scope says it’s good to 400v, I imagine leads should be higher?
    Hoping to keep it around $40 for now. If I start using it a lot, I’ll upgrade later.
     

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