Products > Test Equipment
Recommendation on selecting a used oscilloscope?
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BillyO:
With an old Tek TAS475 selling in working condition for over $500US these days, not buying something new for that price is just silly.  Unless you are getting something in verified working condition for next to nothing, go with something like a Siglent SDS800X HD or a SDS1000X E and get a quality, competent instrument that runs circles around the old girl and come with a warranty.

Of course, maybe you want the challenge of restoring an old beauty and maintaining it and are not really interested in just getting on with a good scope. :-//
TomKatt:
I love CRO gear and still use my HP 180A regularly for analog work. It was my only scope for many years and did virtually everything I needed.  And despite being nearly as old as I am, it powers up every time and operates flawlessly with a nice, crisp trace.

But since getting my Siglent SDS1104X-E and now the SDS800X HD, there is no way I'd buy an old, used CRO unless I was specifically looking for collectible vintage test gear.  For everyday use, modern gear is more reliable and provides a magnitude greater feature set.
Wallace Gasiewicz:
I am with TomKatt and BillyO on this   

Seems to me that the new scopes have so many functions they are in danger of no longer even being called "Scopes"       
I bought an Infinium Agilent Scope used a few years ago and it seems to me that for the price I paid then, you can get a NEW Sigilent with more Functions.   
Please note that I do not have a new Scope and am stuck in Infinium Land.   Maybe not for long though.   

About antique CRT scopes: I really like them.  There are a few things I am aware of that the old Analog CRT scopes do better, but you probably do not need a CRT scope and if you happen to find a use for one, probably a 20 MHz Analog can be found for $20 if and when you think you need it.
Fungus:

--- Quote from: TomKatt on June 18, 2024, 04:15:27 pm ---...with a nice, crisp trace.

--- End quote ---

That "crisp trace" is because it's hiding things from you, it's like only ever working in "hires" mode on a modern 'scope'.

Compared to their predecessors the traces on the new 12-bit DSOs are plenty "crisp" though.


--- Quote from: TomKatt on June 18, 2024, 04:15:27 pm ---modern gear is more reliable and provides a magnitude greater feature set.

--- End quote ---

Two orders.
David Hess:

--- Quote from: TomKatt on June 18, 2024, 04:15:27 pm ---For everyday use, modern gear is more reliable and provides a magnitude greater feature set.
--- End quote ---

They are an order of magnitude more convenient, but I am not sure about having an order of magnitude greater feature set.  They have all kinds of automated measurements, which save time, but it is an oscilloscope, so I am more interested in what the shape of the wave is.

They are more reliable only because they are new and old oscilloscopes are old, but I doubt current DSOs will operate for as long.  How many modern DSOs have failed because of failed storage or loss of calibration data?  If something breaks, throw it away, and buy a new one.

Things which I would love to do with a DSO which would convince me to buy a new one:

1. Gated RMS noise measurements.  My old Tektronix 2440 DSO does this perfectly.  My analog oscilloscopes also do it perfectly, albeit not as easily.  Some modern DSOs that I have tested simply return the wrong results, maybe from making the RMS measurement on the processed display record?

2. FFT noise density measurements - some very high end DSOs can do this, and as pointed out to me, many R&S models, although I am not clear how far this extends into their lower end models.  I need to do a survey.

3. Frequency and phase response measurements - sorry, the current Bode plot thing is a joke, and not even a good implementation of a swept measurement.  I want the superior FFT version which operates in real time.  Some old DSOs support this, but I will probably have to give up and buy a dedicated low frequency network analyzer for this, which is a shame because it should be so easy on a DSO.  Again some R&S models might support this, and LeCroy high end models.

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