Author Topic: Oscilloscope question.  (Read 8112 times)

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Offline shebu18

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Oscilloscope question.
« on: September 14, 2011, 06:08:47 am »
What do you think about this scope? http://www.ekit.ro/index.php?main_page=product_info&cPath=1&products_id=24

I can't afford a digital scope and can't find a ok analog scope. I know what's Dave opinion about the usb based scopes is. i want to use it for debugging arduino problems, see the ripple on my homemade supply unit and so on. There will be nothing very important only hobby stuff. The price in US dollars is about $110-$120.
 

Offline Psi

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Re: Oscilloscope question.
« Reply #1 on: September 14, 2011, 06:24:50 am »
It's got a sample speed of 1mhz, so it's only going to produce a readable waveform when the input is below 400khz.
Unfortunately that's not enough to work with microcontrollers. You really need a sample speed above 20mhz

My advice would be to keep looking until you find a working analog scope above 20mhz, it really is worth it.
If you do end up getting a USB scope you should get a faster one than 1mhz.
« Last Edit: September 14, 2011, 06:33:59 am by Psi »
Greek letter 'Psi' (not Pounds per Square Inch)
 

Offline shebu18

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Re: Oscilloscope question.
« Reply #2 on: September 14, 2011, 06:32:51 am »
Thanks for the answer. So i need to save up and buy a digital oscilloscope. i will post here what i found on the internet.
 

Offline Psi

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Re: Oscilloscope question.
« Reply #3 on: September 14, 2011, 06:40:29 am »
A $100 second hand analog scope is all you really need. As long as it works and is above 20mhz (preferably >50mhz).

The benefits of an analog or digital scope over a USB scope are HUGE.
But the benefits of a digital scope over an analog scope are minimal for most tasks and some things are actually easier on an old analog scope.

« Last Edit: September 14, 2011, 06:45:40 am by Psi »
Greek letter 'Psi' (not Pounds per Square Inch)
 

Offline gregariz

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Re: Oscilloscope question.
« Reply #4 on: September 14, 2011, 07:08:00 am »
I agree... keep your eyes on ebay and you will find a good working 20/40/60 MHz analog scope for around 100 on occasions.

Just dont buy this one:

 http://www.ebay.com/itm/Tektronix-2215-Oscilloscope-2-Channel-60MHz-/140501405355?pt=BI_Oscilloscopes&hash=item20b6894eab
 

Offline shebu18

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Re: Oscilloscope question.
« Reply #5 on: September 14, 2011, 07:14:26 am »
I keep my eyes on ebay, but right now i'm at work and have no access to ebay.
 

Offline shebu18

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Re: Oscilloscope question.
« Reply #6 on: September 14, 2011, 03:52:27 pm »
what about this model? SCHLUMBERGER OCT 569A
 

Offline SgtRock

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Re: Oscilloscope question.
« Reply #7 on: September 14, 2011, 06:13:52 pm »



Dear Shebu18"

--I highly recommend you get a used Tektronix O'scope on eBay. There are lots of great deals for less than $100. Manuals are easily obtained, and if you have a problem you can easily get help here or on other forums. I would get another one myself, but I have to pay my past due taxes first. Times are a little tough right now. Not to worry though, Fresh Prince of Bill Ayres has another job/stimulus bill on the way.

"Three weeks in the lab will save you a day in the library every time" Stanley Williams, HP Labs

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Clear Ether
 

Offline elliott

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Re: Oscilloscope question.
« Reply #8 on: September 14, 2011, 09:55:35 pm »
If you go for a used analog scope, try to buy locally if possible, so you can check it out yourself. My first analog buying experience didn't go so well, it was a B&K Precision 2120, it seemed to check out fine at the seller's house, but when I started using it the traces started drifting down the screen. I'll get around to fixing it eventually, so it wasn't a waste of money, it was a learning experience.

Second scope was a Tektronix 2221A, also bought locally. It had its own set of problems, mostly with the knobs, which I figured would be an easy fix. The analog stuff all checked out perfectly, but the display for the digital functions seemed to have an issue. I talked the guy way down in price and took it home. I found out the knobs are quite hard to get, so I improvised and fixed them. In the process of doing this, I seem to have unintentionally fixed the digital display issues by re-seating all of the cables inside. So now I have a flawless Tektronix digital storage scope for well under $100.

Despite my bad experience, I'd still recommend going for an older analog scope. At the worst, it will have a problem, but with a service manual and some time, most problems can be fixed. It will be a learning experience, if nothing else.


Just dont buy this one:

 http://www.ebay.com/itm/Tektronix-2215-Oscilloscope-2-Channel-60MHz-/140501405355?pt=BI_Oscilloscopes&hash=item20b6894eab
Wow, Israel is not nice to oscilloscopes, I saw this one from the same seller while looking for parts for my 2221A:
http://www.ebay.com/itm/TEKTRONIX-2230-DIGITAL-STORAGE-OSCILLOSCOPE-100MHz-/140487987376?pt=BI_Oscilloscopes&hash=item20b5bc90b0#ht_6067wt_1002

Surprisingly it seems to still work.
« Last Edit: September 14, 2011, 10:17:20 pm by elliott »
 

Offline gregariz

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Re: Oscilloscope question.
« Reply #9 on: September 14, 2011, 10:25:26 pm »
I've bought a few spec-ans and things that wouldnt focus etc on ebay... I took a pic of the problem and sent it straight back

You need to look for this wording in the item specifics...

Used: An item that has been used previously. The item may have some signs of cosmetic wear, but is fully operational and functions as intended.

I usually send it back and then tell the seller I've already sent it so that there is no issue - its going back to them no matter what. Only downside is that I have to pay for return postage... but on a more expensive item that is just the price I pay for trying to get a bargain. On a cheap oscilloscope I would just try to ask the seller a few questions and you should get an idea if they know what's what. But there is a risk I guess, but perhaps no way around at least losing the return shipping if it goes wrong.
 

Offline shebu18

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Re: Oscilloscope question.
« Reply #10 on: September 17, 2011, 01:58:14 pm »
i found on ebay.de a Tektronix 7854. What do you think about it? Or should i go for a Rigol DS1022CD? they are both around 60 euros and are told to work woithout a problem.
« Last Edit: September 17, 2011, 02:00:31 pm by shebu18 »
 

Offline grenert

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Re: Oscilloscope question.
« Reply #11 on: September 17, 2011, 03:17:16 pm »
i found on ebay.de a Tektronix 7854. What do you think about it? Or should i go for a Rigol DS1022CD? they are both around 60 euros and are told to work woithout a problem.
Unless you've got a LOT of room, and never want to move the thing, the 7854 is way too big.  Have you looked at a picture of one of those?  You may get a hernia trying to move it, too.  :o
 

Offline tekfan

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Re: Oscilloscope question.
« Reply #12 on: September 18, 2011, 01:20:35 am »
i found on ebay.de a Tektronix 7854. What do you think about it? Or should i go for a Rigol DS1022CD? they are both around 60 euros and are told to work woithout a problem.
Unless you've got a LOT of room, and never want to move the thing, the 7854 is way too big.  Have you looked at a picture of one of those?  You may get a hernia trying to move it, too.  :o

Don't buy the 7854 please unless you are prepared for it to break down and repairing it. Don't worry this one will go for a lot more than 60 euros.

You might want to look at the Tektronix 2200 series, HP 1700 series, Hameg and Philips oscilloscopes
One can never have enough oscilloscopes.
 

Offline rf-loop

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Re: Oscilloscope question.
« Reply #13 on: September 19, 2011, 07:51:36 am »
I have also one Tek7854 including  "math"keyboard, working condition. Amazing historical scope.
http://www.testequipmentconnection.com/specs/TEK%207854%20SPECS.PDF

But this is NOT for peoples who do not really know how to do and what to do.
This is not "easy toy for just looking some signals visual outlkook".
This scope was real professionals laboratory work horse (in old times).. using this scope and keeping care of it need also "driving licence" - you need 1 year 7854 driving high-school for use it -- hehe.

Today it is Tek collectors unit more that everyday working tool. But yes, it is still good oscilloscope!
Whole this 7000 serie was Tektronix "Rolls-Royce" serie.
Also most of these units with plug ins need more or less service before use. And if do it good it is not easy pece of cake.

Nice unit but if you just need buy 1st or 2nd oscilloscope. Do not buy this.

If practice and theory is not equal it tells that used application of theory is wrong or the theory itself is wrong.
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Offline w2aew

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Re: Oscilloscope question.
« Reply #14 on: September 20, 2011, 03:03:29 am »
...
This scope was real professionals laboratory work horse (in old times).. using this scope and keeping care of it need also "driving licence" - you need 1 year 7854 driving high-school for use it -- hehe.
...

"old times" --- That makes me feel old - because I bought a few 7854s when they were new, to outfit the lab I was working in during the 1980's.
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Offline shebu18

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Re: Oscilloscope question.
« Reply #15 on: September 20, 2011, 06:01:16 am »
I've come to the conclusion that i don't need a oscilloscope but a logic analyzer. I will go for the logic sniffer from dangerousprototypes.
 


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