used oscilloscope

Discussion in 'General Electronics Chat' started by docb, Jul 14, 2011.

  1. docb

    Thread Starter New Member

    Sep 12, 2010
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    I've used other people 'scopes casually over the years, but didn't pay much attention to makes/models. I'm now looking to buy a cheap used one. Will use for some Arduino projects, and serial/MIDI.

    I'm in the LA area so we have TRW swap meet with tons of used CRT scopes for sale. They have many under $100, but at a swap meet not very easy to check out..

    Any tips on what older models to look for? Any notoriously troublesome?
     
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    Even at a swap meet do they have a wall outlet to plug the thing in?

    If not, walk on by.

    If so, plug it in and put the probe into the Calibrate output. (No cal output? Walk away, nothing to see here.) See if you can get a solid nice trace, no horizontal tilt. The probe itself is controlling the rounding of the corners and if you have a tiny screwdriver you can make that go away.

    If it can do that then you are mostly on your way. Play with the volts/div setting and see if it makes sense. You only have 1 input to look at, but look anyway for anything "funny."

    Do a scan of EBay to get a feel for features/manufacturers/prices. Do suspect anything too cheap to be good.

    I've mostly used Tektronics scopes in the past and lots are coming in cheap now on the surplus market.
     
  3. docb

    Thread Starter New Member

    Sep 12, 2010
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    Thanks for the info. This ham radio swap meet had about 50 choices of scopes last month from 20 different vendors, so looking to narrow down which I should plug and and play with...
     
  4. someonesdad

    Senior Member

    Jul 7, 2009
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    +1 on what Ernie said. I would also try every feature of the scope and see that it seems to work or at least doesn't behave funny (I like a sense of humor, but not in a scope). I'd first lean towards name-brand scopes like Tek, HP, and Phillips, but I certainly wouldn't turn down a correctly working version of another brand -- but I'd satisfy myself that it was working correctly. Another tip: put a battery in your pocket that has a known voltage output (better: build a simple voltage reference with e.g. a LM285). Then check that you get proper deflection of the beam on a DC signal too (and this is a good opportunity to verify the AC/DC coupling works). Be sure to check all channels. If the scope is an analog one, you'll probably pay a bit more for a delayed sweep model. I did about 35 years ago, but found I almost never used the feature. YMMV. I always found the analog storage scopes pretty crummy, especially the HP ones. I like the triggering and general good behavior of analog scopes, but I really like the modern features of digital scopes, especially the ability to store waveforms, measure waveform parameters, and digital filters.
     
  5. strantor

    AAC Fanatic!

    Oct 3, 2010
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    military is getting rid of a lot of tektronix scopes from the 90's; 2nd hand electronics outfits are gobbling them up and selling on Ebay; some even calibrate before selling. I got a great scope; working, calibrated, for 120$
     
  6. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    For your applications I would prefer using a digital storage oscilloscope... As Strantor said, ebay is definitely a good option.
     
  7. seecumulus

    Member

    Jul 13, 2011
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    1
    Hello Strantor -

    If you should read this - possibly you could share where you are picking up Used Military OScopes - - for me to look into a purchase for my personal interest.

    Thank you
     
  8. strantor

    AAC Fanatic!

    Oct 3, 2010
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