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

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

  1. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    I found a long-forgotten scope in my shop on the ship. It’s the shop for refrigeration work and there’s NO reason a scope needs to be there. It was on the deck, in a back corner behind a bench and some weird accesses, coated in a film of oil vapors from the engine room. Short version: this thing is totally forgotten about and unnecessary. Nobody knows how to use it (including me), so I’m thinking about asking the chief if I can take it home, since it’s old and the ship will be scrapped in May anyway.
    It’s a Hameg HM303-4. I’ve been watching some videos, and it seems pretty cool. Would it work for a general bench scope for fixing/tuning amps? It doesn’t have any leads, and I don’t have an IEC cable yet to even see if it powers up.
    It’s German made, so at one point, it probably wasn’t junk, but I don’t know about now.
    Hearing from Don how useful they are, I’d love to grab one and learn to use it, and free is a pretty good price.
    Any thoughts?
     
  2. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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  3. 1FretLess

    1FretLess Senior Member

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    ohh yes jump on that
    good from 30-50mhz

    designed for Tv (analog)
    will suffice for Soc / Avr signaling
    with gpio stuff ( pi3 etc)

    find some use with ABS and hall effect
    sensors on cars too!

    snatch it up!
     
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  4. Bobby Mahogany

    Bobby Mahogany Senior Member

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    It's certainly a nice conversation piece.
    You can pretend it's a Top Secret communication gizmo that Interpol uses
    for ship spies... "but I've already said too much. Please don't repeat that".

    I heard there's a "Gay level measurements" switch at the back!
    That could help some.
    :D
     
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  5. V2

    V2 V.I.P. Member

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    High quality scope. Great find!
     
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  6. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    Cool! Thanks guys! I’ll ask the chief about it. I’m sure it won’t be a problem.
    Where can I get the leads for it? Any links?
     
  7. Leña_Costoso

    Leña_Costoso Senior Member

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    I don't think I'd put much into it beside leads.... reusable on other scopes.

    Hell, I got a used 100mhz Tektronics DSO I'd sell for $250, they're that cheap these days. Sold an HP 50mhz scope to for $100 after a very long time on the market. If you look, they are around. Check the Ham Radio hangouts online. A GREAT set of leads might cost you $60-120 ... cheapies much less. We can get by on cheapies for amp work.

    While scopes are interesting, I find the AF signal generator more used. Most of what you need to see can be seen with a good meter. Or you can set up a nice little way to look at crossover (easy to do if you look at conduction of the tubes on a dual trace scope, hard to do if you follow the experts and look at the output on the OT). Then you can say... yup, I been doing it right all along.

    The only time I ever REALLY got good use from mine, is when I ventured into high gain in close quarters amps. Pack a bunch into tiny spaces and you start to get parasitics that'll drive you nutz. The scope helped there, but it takes a bunch of lookin' and doin' to actually see/find problems. Now I avoid the frustration, and try not to pack too much into too close of a space!

    Bah, I sound like a n'er do well. Get the scope. You'll have fun and learn with it!
     
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  8. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    Haha! No, man! That’s very helpful. I do plan to get a signal generator too. I’m leery to plug my iphone into an amp with 600vac/350vdc hiding inside it.
    But I doubt those are too expensive. I’m basically trying to have something else for my imminent workbench so I can build a few amps, tweak, play, maybe even design.
    I’m incredibly not knowledgeable, at present, but learning is so fun, especially at this kind of stuff. That’s my real interest here.
     
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  9. Leña_Costoso

    Leña_Costoso Senior Member

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    I think you'll find a good AF signal generator more expensive than a good scope, due to supply/demand. There are lots of scopes out there, but very few AF signal generators.

    You can get a little one, with almost no calibration, but quite usable for about $100. Hint: Use your guitar tuner or phone app to "tune" the generator!
     
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  10. ehb

    ehb Chief Discombobulator Premium Member

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    Never used one of those... I used primarily Teks and a B&K here and there....

    It'll work fine for audio stuff...

    Hell, I have an ancient green coffee cup screen RCA in my garage that I could use just to look at audio signals... Not gonna measure anything with it....

    I also have a H-P 'big wheel' sig gen too.... (No..... it ain't)

    Summa dat old stuff may be old, but can be reliable as hell....

    Still use my original Fluke 79 all the time...
    I bought it when they first hit the market waaaaaaaaaaaaaaaay back....

    Wish I had an old black Simpson 'brick'.... Anybody that says analog ain't accurate never used a brick.... Accurate as hell if you know how to use it...
     
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  11. Leña_Costoso

    Leña_Costoso Senior Member

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    Got 'em. My 260's... had a few. New one's are still pretty good, and "only" $300ish. Yikes.
    The HP... its old... the "wheel" was broken, but all the parts and bits were there soooo... ya know that black superglue StuMac sells? Hehehehe. Works on the bakelite like a charm!
     
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  12. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    I’ve come across a few simpsons, as well. One was in the box in its styrofoam! No leads, but still shoulda asked about that one. They’re holdovers from when these ships carried radio officers, which they don’t anymore. If I make it back to that ship, I’m gonna ask about that one too.
    They like me wherever I go and tend to be cool about this stuff. I’ve seen a few semi-vintage looking do-hickies that I should have asked about.
    We just use a fluke dmm, an amp probe and a megger.
    That does everything you need on a ship.
    Well, also a 4-20mA generator, but most people don’t even know what to do with those. Last ship I was on, the chief told me the guys before me fried TWO fluke process calibrators.
    TWO.
    Like $1200 a piece.
    440vac?? On a 4-20 circuit??
    Sure!!
    Derp derp derp...
     
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  13. rabidhamster

    rabidhamster Senior Member

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    [​IMG] You said 420 circuit.
     
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  14. Kris Ford

    Kris Ford Senior Member

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    They have (the eqiuv of)RMs, EMs or IC men on your ship? they might be able to help with leads maybe...
     
  15. Kris Ford

    Kris Ford Senior Member

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    Oohh, and I have been bit by 440..while welding rack studs on the deck..in our berthing rehab..knocked me on my asss..

    The stinger lead fell out of the handle...big POP, white light, and I was down..lucky to not have got the full bite!!!

    I became religious about proper lead dressing and clamping LOL
     
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  16. Leña_Costoso

    Leña_Costoso Senior Member

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    No radio officers? Hmm. I take it less then six passengers for hire, or UHF/VHF only, domestic ports of call, no RTTY, under 300 gross tons, etc.... I'm licensed for all that!

    There are 3 kinds of meggers. One is the company "Megger", which originated the (#2) high resistance meter which got called a megger, and also made the (#3) earth ground checkers, also called meggers.

    I use #3 frequently!

    Someplace, I've also got a HiPot tester and I'll be gobsmacked to find it. Its out in the garage "someplace" but not in any box I can easily get to. Sitting here also a function generator, no so well suited for audio, a time base/sync generator, from the old TV days, and someplace again, an LCR/VOM/Freq Counter/Temperature "do all" meter that was ok for C and fantastic for L, which came in handy for pickups and OTs.

    Whoever gets all this crap when I die is gonna either love it or hate it.
     
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  17. KP11520

    KP11520 Senior Member

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    Hey M&M,

    The best place to find out if it's worth taking and using is a forum called www.DIYAudio.com If you like to tinker with electronics, whether amp or pedal stuff, no better place to learn and get help!
     
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  18. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    Haha! There are a few bums I’d consider “passengers”, but they’re all on articles. Less than 6, though.
    I think I’ve seen a brand name megger before, but mostly they’re properly labeled “megohmeter”.
    For anyone who’s unfamiliar, a megohmeter (“megger” as the industry term, and “megging the circuit” as the usage of it) tests insulation resistance of ship’s circuits. Any grounds can cause failures or fires. We don’t have a neutral ground, both (or more often in the cases, all three) sides are hot. It applies a higher DC Voltage and measures the leak to ground in Mohms. Higher the better.
    Fun fact: they can do 500vdc and some do 1000vdc.
    I got kissed my the 500 once, and I’ll never in my life do that again. Extremely low current, but geez.... It could have been avoided if the chief was a better listener, but that’s more than I’ll type out on a phone. ;)
    We use them most commonly to test for grounded 3-phase motors and cabling.
    Most of the mates get their licenses as radio officer so I imagine that covers the requirements.
    It’s always funny when they basically can just use the thing (GMDSS) but don’t know the first thing about ohms law.
     
  19. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    Hopefully maybe in the next few days I can find an IEC cable and see if it even powers on.
    I’m keeping expectations low, but I can’t do anything about my hope.
     
  20. Kris Ford

    Kris Ford Senior Member

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    Steal one from a PC! :D
     
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