Products > Test Equipment
Choosing an oscilloscope
<< < (22/25) > >>
0culus:

--- Quote from: george.b on October 13, 2020, 03:32:22 am ---
--- Quote from: 0culus on October 13, 2020, 03:04:41 am ---I really don't get this almost cult-like belief around here that beginners are to be coddled and spoonfed and protected from–God forbid–having to learn to fix old gear.

--- End quote ---

Absolutely nothing wrong with beginners learning to fix old gear. But there's a difference between someone getting an oscilloscope as a tool for other ends, and someone getting an old fixer-upper oscilloscope as a project in itself - a project which is usually easier to do, by the way, if you already have a functional scope.

--- End quote ---

So? Maybe they want to learn, has anyone in one of these threads ever asked them? Probably not since the OP is usually running away as fast as possible after seeing the argument break out.  :-DD 

FYI, I fixed a Tek 585A with a serious short to ground, with nothing but a couple of multimeters and the actual printed manual in hand. Two shorted diodes in the rectifiers for the B+ supplies. Couple of new 1N4007s later it was good to go. Not that I would recommend a beginner be poking around in a Tek tube scope...those B+ supplies will not suffer a moment of stupidity...but you don't necessarily have to have all the fancy gear to fix stuff. Some basic tools, a desire to learn, a manual, and more experienced folks to get advice from.
tautech:

--- Quote from: 0culus on October 13, 2020, 05:20:20 am ---
--- Quote from: george.b on October 13, 2020, 03:32:22 am ---
--- Quote from: 0culus on October 13, 2020, 03:04:41 am ---I really don't get this almost cult-like belief around here that beginners are to be coddled and spoonfed and protected from–God forbid–having to learn to fix old gear.

--- End quote ---

Absolutely nothing wrong with beginners learning to fix old gear. But there's a difference between someone getting an oscilloscope as a tool for other ends, and someone getting an old fixer-upper oscilloscope as a project in itself - a project which is usually easier to do, by the way, if you already have a functional scope.

--- End quote ---

So? Maybe they want to learn, has anyone in one of these threads ever asked them? Probably not since the OP is usually running away as fast as possible after seeing the argument break out.  :-DD 
--- End quote ---
Yeah that's the hard bit, deducing a newbies experience or even their want to dive into the innards of a CRO whereas they might just want to play with basics to look at squiggly lines or 555 timer stuff.  :-//


--- Quote ---FYI, I fixed a Tek 585A with a serious short to ground, with nothing but a couple of multimeters and the actual printed manual in hand. Two shorted diodes in the rectifiers for the B+ supplies. Couple of new 1N4007s later it was good to go. Not that I would recommend a beginner be poking around in a Tek tube scope...those B+ supplies will not suffer a moment of stupidity...but you don't necessarily have to have all the fancy gear to fix stuff. Some basic tools, a desire to learn, a manual, and more experienced folks to get advice from.
--- End quote ---
Been there done that and earned the badges along the way which initially lead me down the road into getting a distributorship where the last few years business has replaced hundreds of CRO's with something more useful for the novice as it's much easier to grab and post a screenshot when seeking advice/mentorship.
This screenshot capability primarily led me to DSO's where my first DSO was a Tek TDS2012B, the first in that range that had USB so to make it dead easy.
Chuckled with a long time customer today about these old Teks as he still has one but none of his staff want to use it and instead fight over his little Siglent X-E's instead.  :-DD

Amazing to see what he does with these entry level DSO's ......not that I can share much about his IP other than to say it's EV wireless charging over 200mm to the tune of 20kW !  :o
2N3055:

--- Quote from: tggzzz on October 12, 2020, 11:26:49 pm ---
--- Quote from: 2N3055 on October 12, 2020, 10:35:23 pm ---And "digital scopes are buggy" is blown out of proportion...

--- End quote ---

No more so than "all old scopes are broken"


--- Quote ---As I said many times, advising beginners to purchase 40 years old scope in unknown state is at best naive..

--- End quote ---

Strawman argument. Nobody has suggested that.


--- Quote ---You cannot have 40 year old analog scope as your first and only scope as a beginner.

--- End quote ---

Absolute nonsense.

Having taught beginners, they understand them better than to complex modern scopes with subtle and important config setting buried in a menuing system.


--- Quote ---My advice...

--- End quote ---

Is valid from one limited viewpoint.

--- End quote ---

You and most other analog scopes aficionados seem to take this personally and emotionally.
I don't disagree with your decisions for yourself. I couldn't even if I wanted to. They are your decisions about your life.

And, to make it clear, I also used analog scopes much longer than I've been using digital ones. I do have nostalgia about them. I love them, the green glow wakes up good feelings and memories of simpler times when things seemed more magical...

But magical machines they're not.

And, yes 40 years analog scopes you can buy/get today are mostly broken, most of them quite literally.
By that I mean exactly that. They are not old junk that rotted because it was bad quality. Quite literally, they were made of gold and all kinds of precious materials, and if they don't have much on hours, they still can have 10s of years in them...
But most of them are broken, mechanically, abused, butchered inside for whatever reason. If you can get one that was never badly maintained (butchered inside), not broken mechanically, was kept at room temperature without condensation in clean environment, etc..etc.. You might get one of those mythical beasts you talk about...
But those specimens are becoming as rare as dragons...... All you can buy now is simply broken crap...
Not because they are bad machines (they were excellent quality and made to last), but because in 40 years they were abused, dropped, shocked, connected to wrong voltages, then scrapped, sent to recycle plant, dropped from the back of the truck on the ground, was there on rain for years, salvaged, cleaned a bit and now being sold to you...

And, if, by chance a good one appears, getting that one is pure luck.

So, yeah, statistically speaking, if you buy analog scope from just anywhere today, you're gonna get crap.

And again, beginners.

Beginners don't have skills to choose one that is good. They don't know how to check if it functions right.
They don't have other equipment needed (calibrators, signal generators...)
So they are buying a cat in a bag...

If something is wrong they also, have neither skills nor equipment to repair something as complicated and sophisticated as an oscilloscope..

That is not something I would recommend to a beginner. That is what I would say to a beginner 20 years ago when there wasn't choice. Scopes where as expensive as a car, and for a hobby, only choice was to get an used old one and hope for the best.
Today be we have a better choice.  For same money people ask on Ebay for " an excellent condition Tek scope, untested, as is" (that by the way is missing half buttons and knobs), you can buy something that works up to spec, has warranty, and has 20x times more capability that green wiggle machine that cannot: freeze capture on the screen, do probe attenuation math, do any measurements aside cursors (if you have advanced model), show slow sweeps, have any other trigger than slope and video (which is of very limited use today), and literally hundreds of other functions..



--- Quote from: 0culus on October 12, 2020, 11:31:43 pm ---CROs, due to the exact relationship between the crt trace and the input, have a level of tactile-ness that DSOs can't match. This is really important for a beginner. Running a modern scope is a LOT easier if you know how to run a CRO. Well, cussing the damn thing because of the menus aside. I &%#$ing hate menus. This is part of the reason I choose to use old scopes and spectrum analyzers in my personal lab.

--- End quote ---

I couldn't care less for "tactile-ness". I don't have scope to "gently stroke it's buttons in a bliss".
It's an instrument. It should do its job. My job is to learn how to use it.

Running a DSO is much easier if you NEVER used CRO. Most of the stupid questions, misunderstanding, and those annoying whinings (this scope is so baad, because they don't call it same as Tek did...) are from people coming from CRO. To learn to use DSO effectively, you need to learn different ways how DSO is used, instead of whining how "things are not as they are supposed to be"...
Those that learn on DSO simply learn how it works from the beginning and get on with it... And on DSO, they learn vertical controls, timebase, basic trigger so quickly (that is all they can learn from CRO), not many questions are about that. They learn all that in few days.
Questions are about FFT, or measurements or digital triggers.. All the stuff that CRO cannot teach them because it doesn't have it.

And some DSO even have demo signals that you can use as small course to learn how to use it. I used those with my son (on a 3000T) and it was very helpful.

As a side note to all DSO manufacturers: " Yo idiots, that demo board shouldn't cost 250 USD. It should be 20 USD, or free, and make 20 pages PDF with short course. For example see how Keysight, and R&S does it on some of their scopes."

My son literally learned to use Micsig STO1104C in two hours.... than second day we spent few more hours on details of persistence, display modes, decodes... With Keysight 3000T it is not that simple, because it has hundreds more functions. On that one I simply have manual handy. I consult it sometimes about details. I make it a point not to learn by heart anything that I don't use all the time.

Truth is, lots of that advice about CRO scopes was still good advice maybe 10 years ago.. But it isn't anymore. In meantime, world changed a lot. It's time to move on... And CRO scopes are going the way of TTL based arcade game, retro Z80 computing, etc.. If you like that stuff, that is great. I love it too.

But IBM PC XT is not something I would recommend to friend as an answer to question:
"My friend: Hey, Siniša, you know this computer stuff...I have no clue about this, but I would like to learn programming in C. What computer you would recommend me to buy to get me started. I want something small and simple and cheap..
Siniša: Well, my friend, there is this cute little thing called Raspberry PI.........."


I'm sure you do get this analogy.. And it is very accurate...

Regards,

Siniša
David Hess:

--- Quote from: 0culus on October 12, 2020, 11:31:43 pm ---CROs, due to the exact relationship between the crt trace and the input, have a level of tactile-ness that DSOs can't match.
--- End quote ---

I disagree; there is nothing which prevents a DSO from responding to user controls with a latency of one display frame, which is fast enough to be visually indistinguishable, except poor design.
tv84:

--- Quote from: David Hess on October 13, 2020, 08:36:35 am ---one display frame, which is fast enough to be visually indistinguishable

--- End quote ---

Nitpicking a little >:D: even with 120Hz/144Hz displays the human eye can see the difference.

Nitpickings aside, I disagree with you. There are a lot of things being done by the processors/FPGAs nowadays to stop that from happening, in "economical" terms. Unless you specifically build a gaming DSO. In that case, with the right money poured into the design, sure you can have those latencies.
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod