Digital O_scope or not?

[diydidi]

Hi there everyone.
I have been doing electronic Audio Repairs for about 5 years now. I have an analog Tektronix 453 O-scope, that I picked-up second hand a couple of years ago. Recapped it, and it works great.
With the new digital age and all, is it a good idea to invest in a good DSO? I was looking at the Rigol DS1052E.
I mean will it come in handy over my Tek scope???

[Enzo]

You have been doing repairs for five years, and had a 453 for a couple years. In that last couple years, make a list of all the times you ever thought to yourself "Oh how I wish this 453 could do_____" In what way does the 453 NOT fill your needs. THAT would be your reason or reasons to get a new scope. I would imagine that old tek scope works just perfectly for your needs.


WHat addfitional capability would you expect from a DSO? DSOs are good for such things as catching little glitches on computer data lines. Are you working on those? DSOs can store repetitive waveforms, you can compare cycle to cycle for variances, you can check for "jitter." ANy of that sound useful to your needs? SOme of them might include analytical functions like FFTs. Need those?


Bottom line is, when spending this money for a new scope you need to have a clear reason why you might need such a scope, and be aware of what your older/existing equipment can;t do that you need.

[Tom Phillips]

In addition I offer the following personal comments:
1) Digital scopes can get expensive fast.
2) Inexpensive digital scopes can display some really annoying waveform artifacts like what I think of as the crawling line of ants display. To my eyes that makes a nice clean sine wave look noisy.
3) Once the warranty expires the cost of repairing a digital scope will most likely be prohibitive. Maybe not even possible.

Digital scopes do have their place of course for features already pointed out.

Cheers,
Tom

[km6xz]

The old one will still be needed for tube circuits since the digital scopes most digital test instruments are killed easily by probing live circuits. Drawing a an arc by touching a probe lighting to a plate lead is not unusual and is not something the instrument is designed for.

Look at its display for a while before buying, does it really display residual noise smoothly or is it burbling with aliasing chatter with no signal applied? That is normal for 8 bit scopes and is irritating to see and you will never see a truly clean waveform. High frequency noise in a lower end digital scope can result in aliasing noise at pretty high amplitudes.
My suggestion, if you really want the features of digital scopes like the calculated values, FFT and color displays, all really cool to have, is to keep both a good analog scope and versatile digital scope on the bench and know the strengths and weaknesses of both. If you are only working on digital gear you can get by with the digital scope alone.
If on the other hand, you are dealing with 60 years of electronics technology like most shops, an analog scope and a real VTVM are very handy to work on circuits which can be dangerous for digital test gear. An old Heath VTVM is good enough for tube circuits, but a HP410C would be best. You can't kill those on tubes circuits.
Maybe upgrading the analog scope to one with a larger display like a 465 would be useful because it is something you stare at for hours every day and has a more pleasing look to wave forms that are erratic or noisy. You can get a 465M for about $150

[imaradiostar]

Older tek scopes are fabulous- they're mostly built with parts you can still get and they're simple enough that if you had to sub another part it's not difficult.

That said, I doubt you'll kill one!

My everyday scopes are the inexpensive (and "slow") Tektronix 5k series but I keep a Tektronix 561A around because it's mostly tube and even tougher to kill. If there is an EMP or bomb near me and all of the solid state stuff quits, I'll have bypassed the electronics in my diesel jetta and hit the road with the help of my trusty tube scope!

We have digital and analog scopes at work and it's amazing how often we'll use the old Tek 465's and 468's for anything that's higher voltage than microcontroller work. They just work better. I can't describe it.

I still would like to find a Tektronix 5D10 plugin for my 5k scopes. It'd be nice to do digital measurement every once in a while and it adds that feature to the old scopes.

Jamie