Old OSCILLOSCOPES
Clock Loop
Posts: 2,069
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...
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...
Comments
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Post Edited (Paul Baker) : 11/3/2005 10:45:40 PM GMT
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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I just bought a· 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
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 Smile shoot.
Christmas is coming. Start saving and drop hints.
Hope this helped some,
kenjj
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 channel·to 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.· 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 [noparse][[/noparse]it requires a lot of support electronics to properly do the job]
These items are fondly referred to as boat anchors. And we often·say, 'No thank you, not in my garage.'
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Post Edited (Kramer) : 11/4/2005 9:25:42 AM GMT
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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I have a Audio program[noparse][[/noparse]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 [noparse][[/noparse]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)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan