Oscilloscope - Any advice (2nd hand CRO v LCD)

Discussion in 'General Electronics Chat' started by simonbond, Mar 13, 2014.

  1. simonbond

    Thread Starter New Member

    Jun 21, 2013
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    0
    Dear Forum,

    My 1960s oscilloscope is finally getting a bit old & troublesome.

    It's an S.E Labs SM111 which I have had since 1988, when I bought it from a test equipment dealer in Reading UK for £250. it's a fairly standard 18MHz dual trace, which I use for general purpose use for analogue & fairly slow digital/embedded micro projects.

    It has another advantage of providing heat for my shed when I use it!

    I want to replace it with something newer, but am not sure if I should go for a used Cathode Ray Oscilloscope (CRO) from a respected manufacturer such as Tektronix/Philips, or should i look at a newer type LCD model by one of the imported Hantek/Tekway/Rigol makes.

    I have about £200 to spend. My requirements are dual channels as a minimum, although I can buy models with upto 4 channels. I think I should be aiming at about 100MHz bandwidth since I will be using it on PICS/Arduinos to about 20MHz.

    On one hand I'm tempted towards a traditional type CRO, but cannot ignore the modern LCD ones.

    But I have never heard of some of these manufacturers, so am worried about the risks of buying such. Therein lies my quandary!

    It would appear that the modern LCDs specification would give much more capability; such as Spectrum/FFT Analysis, Logic Analysis etc. I've also seen some claims that extra bandwidth may be 'unlocked' by updating firmware, but this is not really a factor that would influence me greatly.

    Any advice or suggestions would be greatly appreciated, as I can find discussion from both points of view.

    Many thanks,

    Simon B.


    Sent from my iPhone:-
    ---------------------------------------------------
    Simon David Bond MEng, BSc(Hons), IEng,MRAeS.
     
  2. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    4,887
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    You can't go wrong with a Rigol. Cheap and great quality.
     
  3. MrChips

    Moderator

    Oct 2, 2009
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    I would go with a 2-channel 100MHz DSO and I would try to ignore any hype about spectrum/FFT analysis and logic analyzer.

    The most important feature of a DSO is the fact that it can capture a one-shot event.

    The hard part is choosing between a Rigol and Owon or any other contenders. I think it is going to cost you a bit more than £200.
     
  4. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
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    My suggestion is to go digital scope, and go for the large 7 inch, 800x480 pixel screen. Many cheap brands have the big hi-res screen now.

    You'll spend years looking at fine details on that screen and you will kick yourself if you bought a 320x240 pixel 5 inch one!

    Their features are pretty much the same.
     
  5. simonbond

    Thread Starter New Member

    Jun 21, 2013
    5
    0
    Thanks,

    I'm going to get either the 70MHz or the 100MHz Hantek:-

    Hantek DSO5102P 100MHz 2CH Digital Oscilloscope 1GSa/s, or
    Hantek DSO5072P 70MHz 2CH Digital Oscilloscope 1GSa/s

    These seem to offer much more than my current machine.

    Thanks again,

    Simon B.
     
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    I've got the same Hantek 5102 100MHz unit, it's pretty good. :)
     
  7. ian field

    Distinguished Member

    Oct 27, 2012
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    There's a large turnover of people getting rid of their old CRO and upgrading to a trendy new digital/LCD job.

    You should be able to get something reasonably shiny for a fair bit better than £250.

    Initially I'd go for a CRO that would be pretty good to keep as a spare while I bide my time for an LCD bargain to come my way.
     
  8. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    £200 isn't going to get you a very good LCD model from a respectable company. Your best bet would be what MrChips suggested. Try to get your hands on a DSO scope from HP or Tektronix, CRT is fine. I have several of them myself, and they work great. 2-channel 100MHz would be my bare minimum recommendation, though I'm sure you could find some better (4-channel, higher bandwidth) scopes for under £200 on ebay. That is what I would suggest.

    Good luck!
    Matt
     
  9. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    I got a nice used Tek 100 MHz dual trace analog of ebay for about $250, was calibrated and came with a warranty.
     
  10. Zerotolerance

    Member

    Sep 18, 2011
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    10
    You can get good quality scopes for cheap on ebay or a government liquidation website easily in the $150-200 range. I have a Philips/Fluke PM3335 and love it!
     
  11. nigelwright7557

    Senior Member

    May 10, 2008
    487
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    There are still plenty of crt oscilloscopes on ebay.
    I recently bought a better one than I had for £100.
    I much prefer a crt to an LCD.
     
  12. ian field

    Distinguished Member

    Oct 27, 2012
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    Even with a cal certificate, I've never been totally trusting of a CRO - I use them primarily to see the shape of the waveform, if frequency and amplitude are that important I verify with instruments better suited to the task.

    When I was a novice, owning a scope was the holy grail - as I gained in experience, the scopes got used far less often.
     
  13. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    Oscope was never intended for precision measurements, but it's good enough for about 99% of what I did when designing.
     
  14. MrChips

    Moderator

    Oct 2, 2009
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    If I can get a measurement on the oscilloscope to within 10% that's good enough for me.
     
  15. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    When I was in school in 1978, one of the instructors claimed nobody could see THD of less than 1% on a sine wave displayed on a scope.

    Turns out he was wrong about that. I could.
     
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