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Thread: Old OSCILLOSCOPES

  1. #1

    Default Old OSCILLOSCOPES

    Are old OSCILLOSCOPES worth buying? I am talking purchasing them for under 50$....

    Scopes like the TEKTRONIX 2465A

    or

    LECROY 7200A PRECISION DIGITAL OSC

    or others...

    I ask because I can't afford 100$+ for a newer one.

    Why shouldn't I buy older o-scopes?

    Why should I? (other than price,,, more features?)

    I am asking this because I have never used an o-scope, I know what they are for, and don't know the limitations, and needs..

    My desire is to use the o-scope to view different things. Like the communication of a device on a computer COM port. etc...
    Should I get a digital o-scope over an analog?

    Sorry I know I am opening a can of worms here, but I have no idea what Im doing here.. LOL (but that dosen't stop me from learning)
    Mabee some of you can tell me what I might be able to do with these old scopes...
    Last edited by ForumTools; 10-01-2010 at 12:42 PM. Reason: Forum Migration

  2. #2

    Default

    Im a little shocked that you can find a TEKTRONIX 2465A for $50, the used and refurbished ones Im seeing on the net are $800-$1000. And the LECROY is even more suspicious since it is a 1Gs/s model. Im wondering if the one you've found is sold as-is. The problems with buying old o-scopes is the same as buying any used electronics, it may not be functional, it may be on it's last legs, and if it's refurbished, but not a company certified refurbishment, therefore it may have had the malfunctionioning part replaced, but other parts may be nearing thier end of life.

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    Last edited by ForumTools; 10-01-2010 at 12:42 PM. Reason: Forum Migration

  3. #3

    Default

    Yeah, im pretty sure the stuff is AS-IS..
    Last edited by ForumTools; 10-01-2010 at 12:42 PM. Reason: Forum Migration

  4. #4

    Default

    If the price was closer to the refurbished price, Id say go for it. But the fact that $100 is a steep price to you makes me think that you can't afford to take the chance of spending $50 on a non-functioning unit. Also keep in mind the older scopes are quite heavy (the scope I borrowed from the local university in the 80's was roughly 30 lbs), so shipping costs will also be a significant factor. If you have any local independent electronic component dealer (they are getting rare'r by the day, and don't bother going to RS) go ask them if there is any local source for used and working o-scopes. Universities used to be a great source but most major universities nowadays have inventory control programs (to prevent employee theft), UF had two warehouses filled top to bottom with old computers, monitors, keyboards, printers etc but you couldn't purchase them. Every 5 years or so they would sell the entire lot to a liquidator.

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    Post Edited (Paul Baker) : 11/3/2005 10:45:40 PM GMT
    Last edited by ForumTools; 10-01-2010 at 12:42 PM. Reason: Forum Migration

  5. #5

    Default

    An old analog scope won't do you much good to look at comm signals.
    They only work with repetative signals or very slow signals that you see changing.
    This is because they don't store the waveform, so you have to see it as it's happening.

    Also scope probes can run $20-$50 each.
    Bean.

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    Last edited by ForumTools; 10-01-2010 at 12:42 PM. Reason: Forum Migration

  6. #6

    Default

    Hi,
    I just bought aи working and calibrated Tek 465 on e-bay for $125 and that was a steal. It is a decade older than the 2465.
    I agree that a $50 scope is not going to work very well.

    Be very cautious about what you are getting, just bacause you can only afford $50, doesnt mean that the O-Scope is any good.

    Alan Bradford
    Plasma Technologies
    Last edited by ForumTools; 10-01-2010 at 12:42 PM. Reason: Forum Migration

  7. #7

    Default

    If you can live with really low speed access barely good enough for slow serial comms, you might want to consider sound card oscilloscopes. I did a Google search on "sound card oscilloscope" and got lots of hits. These are software o-scopes that use the PC's sound card to digitize signals coming in on the microphone port. Most of these expect you to be connecting a microphone or keyboard. These are free versions that you download. They don't state what their frequency range is, but being audio devices, providing double sampling for CD quality results, you can figure the top end is 44kHz.

    There's one commercial version that has a downloadable seven day free trial, sells for $25:
    http://www.virtins.com/page2.html#Oscilloscope
    This is rated for 192kHz input sample rate, more than good enough to study simple serial comms. These guys also have a sound-card-spectrum-analyzer, $35, Both for $50. The $50 dollar unit also does signal generation, including sine waves and white noise. However, nowhere do these people, or anyone else mentioned later, discuss how to form a typical handheld probe you can use with these units.

    Most BASIC compilers offer some kind of software o-scope, but none are under $100 up front.

    There's a device called the LabJack U12 (http://www.audon.co.uk/labjack.html) that will do an o-scope as part of its software, but, like the others, the frequency is limited. The price is right, though:$120, last time I looked. It does several other functions. Check it out.

    Perhaps your best bet is to try and find some electronics/ham radio flea market. These are usually hosted by community colleges. you will find several old o-scopes there, but not necessarilly under $100. And, like the units on Ebay, the quality and reliability are a crap shoot.

    Christmas is coming. Start saving and drop hints.

    Hope this helped some,
    kenjj
    Last edited by ForumTools; 10-01-2010 at 12:42 PM. Reason: Forum Migration

  8. #8

    Default

    If you can live with very low speeds, you might as well use Win-scope [the pc software for free].
    You already have a sound-card interface and it gives you two channels.

    The most interesting thing about the old Tektronic scopes are the 'front-end preamplifiers'. Plug in units vary from one channelиto mutilples. If you could get an old two signal plug in that uses the 12AX7 tubes, it is an extremely flat linear preamp for tube stereos. Years ago, I cannabalized one, but never got the power supply built.и Audiophiles might pay a bit for a highly engineered preamp.

    BTW, the power supply and calibration for the old tube scopes is where they created a tremendous re-calibration overhead. I suspect anyone that wants to sell one for $50, has a calibration problem [it requires a lot of support electronics to properly do the job]

    These items are fondly referred to as boat anchors. And we oftenиsay, 'No thank you, not in my garage.'

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    ииииииииииииииииииииииииииииииииииииииииииииииииии ииииииииииииииииииии Warm regards,иииии G. Herzog [и黃鶴 ]иin Taiwan

    Post Edited (Kramer) : 11/4/2005 9:25:42 AM GMT
    Last edited by ForumTools; 10-01-2010 at 12:42 PM. Reason: Forum Migration

  9. #9

    Default

    Great replys everyone! Thankyou.
    Last edited by ForumTools; 10-01-2010 at 12:42 PM. Reason: Forum Migration

  10. #10

    Default

    So after checking out all the different software out there to turn your sound card into a o-scope.

    I found out they all kinda SUCK.

    I have had better results with literally recording the data like a sound clip and then zooming in with my favorite sound recording program (cool edit pro) aka adobe audition.

    Check out the image attached. It recorded the clock line and the data line coming form my BS2 to a serial LCD. (using shiftout)
    I was able to see each clock cycle perfectly, and each high and low data perfectly. (you just have to zoom in enough)
    I guess I just found my LOW END storage scope.
    My sound card is an old SBLIVE (pci)

    I used buffer hardware to cut the voltage down. The inputs were connected directly with the BS2's P0, P1.... So I am putting in 5volts. And after the buffer hardware, it puts out about 1.5 volts to my sound card line in. (look at image)

    Post Edited (BPM) : 11/5/2005 1:11:17 PM GMT
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    Last edited by ForumTools; 10-01-2010 at 12:42 PM. Reason: Forum Migration

  11. #11

    Default

    Cool Edit is indeed a fantastic program I have the 96 lite version, same as 2000 sans spectrometer, only 3 function groups at a time, but I just restart it to obtain a different group, a free program that outperforms most commercial sound editing programs with no loss of functionality, just a minor annoyance.

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    Last edited by ForumTools; 10-01-2010 at 12:42 PM. Reason: Forum Migration

  12. #12

    Default

    Heh. heh. You surprised us all.
    I have a Audio program[an MP3 recorder and editor], but I never thought of using it as a recording O-scope. It can go on for hours.

    Anyway, they are all limited by the ADC in the sound card and related computer inards.

    And, they all seem to leave you without any reasonable emprical callibration [because you have to externally divide voltages over about +3 and time bases are somewhat ball-parked].

    So the audio program is just as good at giving you something to work with a beginning.

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    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ииииииииииииииииииииииииииииииииииииииииииииииииии ииииииииииииииииииии Warm regards,иииии G. Herzog [и黃鶴 ]иin Taiwan
    Last edited by ForumTools; 10-01-2010 at 12:42 PM. Reason: Forum Migration

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