Which oscilloscope? / General Science and Electronics / Forums

Forums

4hv.org :: Forums :: General Science and Electronics

« Previous topic | Next topic »

Which oscilloscope?

first previous 2 3 4 5 next

Move Thread

LAN_403

PhilGood

Tue Jul 10 2012, 09:13PM

Registered Member #3806 Joined: Sat Apr 02 2011, 09:20PM
Location: France
Posts: 259

I read many topics on seeedstudio forum in the Tech Support >> DSO Quad section

This (and many of the posts in this thread) gave me some understanding of why it is so hard for a digital scope to behave close to an analog one.

I'm definitly going to buy an analog scope as my first one.

I think a digital scope might be a good choice for a 2nd scope, after comparing many models, it seems 500$ is the minimal price to get something decent.

Steve Conner

Wed Jul 11 2012, 06:32AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Yes, digital and analog scopes complement each other, a really well-equipped lab should have one of each.

Tektronix's Digital Phosphor scopes are the most "analoguey" I've seen. However they are seriously expensive.

PhilGood

Wed Jul 11 2012, 07:50AM

Registered Member #3806 Joined: Sat Apr 02 2011, 09:20PM
Location: France
Posts: 259

I was seriously considering buying the 5441 :

But there might be a big problem with this scope, because of the 5A22N modules that have a bandwith of only 1MHz !

5a22n user manual:

I really don't get why Tek made a module with such a low bandwith for a mainframe that has a capability of 50+ MHz ... ???

I could try to find 5a48 dual trace amplifier modules, they have a bandwith of 50MHz

, but there aren't many available, and they are all sold "as is"...

______________________

I found a very nice gallery of Tektronix old models. It provides descriptions and pictures of circuitry for many old scopes and plugins.
The site also features an HP gallery and many other brands misc test equipments. Repair instructions for some models.

Shrad

Wed Jul 11 2012, 09:10AM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

I have one or two plugins for a 5441, and I might not live far away from your location (Belgium, 20 mins away from Lille)

If you buy it, be sure to send me a PM and we'll work something out

Steve Conner

Wed Jul 11 2012, 07:44PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

I think the 5441 and 5A22 would normally be used for applications like looking at ECGs in a biology lab. They have very high gain (the knob goes down to microvolts per div) and the low bandwidth is a necessary consequence of the high gain.

Not really a good choice for a general-purpose lab scope.

PhilGood

Thu Jul 12 2012, 12:10PM

Registered Member #3806 Joined: Sat Apr 02 2011, 09:20PM
Location: France
Posts: 259

Oh, true... I didn't notice the 5a22n has such a high gain.

That might also explain the reasonable price of this hard to sell unit.

PhilGood

Thu Jul 12 2012, 06:43PM

Registered Member #3806 Joined: Sat Apr 02 2011, 09:20PM
Location: France
Posts: 259

For the same price, would you rather get a 465, a 475, a 2213 or a 2225 ?

Assuming they are all in perfect working condition and good cosmetic condition.

PS: Sorry for the double post, but I'm about to buy a scope on Ebay, and good opportunities sell quickly... thats why fast advices might help a lot. Thanks for your understanding

Paul_J.

Thu Jul 12 2012, 11:26PM

Registered Member #5436 Joined: Sun Jun 24 2012, 01:44AM
Location:
Posts: 39

Hi,

However , the first generation 465s have been around since the late 60s, so they might not be as reliable as you would expect if it's all original. I'm not too sure, but I'm pretty sure at least some of the transistors were germanium.

PhilGood

Fri Jul 13 2012, 11:56PM

Registered Member #3806 Joined: Sat Apr 02 2011, 09:20PM
Location: France
Posts: 259

Paul_J. wrote ...

Hi,

However , the first generation 465s have been around since the late 60s, so they might not be as reliable as you would expect if it's all original. I'm not too sure, but I'm pretty sure at least some of the transistors were germanium.

Thanks Paul_J for the comment.

This is an important aspect I have not considered so far, but I understand a 40yo equipment might have defective/prone to failure components leading to a loss of accuracy in measurements.

I had a look a Tek scopes on ebay.com, and I would say there are two kinds of offers:

#1: "as is", "powers up", "good condition", etc... offers

#2: Fully reconditioned and calibrated equipment, that cost x3 more than #1

I now realize I might have to spend a lot more than I thought initially for a decent analog scope, even if it's a 30-40yo model like the 465/475 series.

Now my question is : can you get a decent scope that can be used for serious work from a #1 kind offer ? Or is it highly recommended to buy an old scope from a #2 kind offer ?

Ash Small

Sat Jul 14 2012, 07:06AM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

You 'can' get a good 'scope from a #1, but it will always be a gamble. I do this a lot, trying to 'read between the lines'. Often the people selling no nothing about 'scopes, so they can't test properly, etc.

Obviously, paying three times more for a 'guarranteed' 'scope has some advantages, though.

Most sellers will accept returns, so it may not be as much of a gamble as you might think. It 'is' possible to get a bargain.

Personally, I'd buy a #1 and test it with a sig. gen, etc. You'd still have enough money left to buy two more #1's if necessary, but that choice is up to you.

Even a #2 could fail after a short period of time, especially if mis-used.

(As I said in a previous post, I bought a cheap old analogue 'scope with no IC's partly in case I blew it up due to my ignorance. I wouldn't want to deatroy an expensive 'scope building my first project using it, but others may have different opinions.)

first previous 2 3 4 5 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob