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Oscilloscope Question

Supercap2F

Mar 22, 2014
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Hi Everyone!

I'm going to get a used dual trace oscilloscope soon and I was wondering if there is a good way to see if it's in good working condition (like a test to run on it).

Thanks :)

Dan
 

Arouse1973

Adam
Dec 18, 2013
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Difficult to check all the functions unless you can borrow it for a while. But you could hook the scope probe up to the calibration output of the scope and check the time base voltage and trigger parts on each channel and the brightness control if it has one.
Adam
 

davenn

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Sep 5, 2009
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In addition to Adam's response

it should have an intensity/brightness control, haven't seen a scope without one.
also check that the trace can be well focussed ... nice sharp line/curve
check both channels that on the same settings show the same signal level from the calibration output test point

check if the scope looks in good condition, ... has it been well looked after or has it been banged and bashed around ? .... does it stink of cigarette smoke ?

Dave
 

jpanhalt

Nov 12, 2013
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Are you looking at digital or analog scopes?
Is the display a CRT or LCD?
What price range?
Portable or benchtop?

John
 

Supercap2F

Mar 22, 2014
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Right now I'm not really looking at a certain type of oscilloscope (besides it having 2 channels). I found one on ebay that I liked but I got outbid right before it ended (it was a bk precision 2160). I have a really limited income so I'm looking at them in the $100-150 range.

Dan
 

jpanhalt

Nov 12, 2013
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It is perplexing that you would bid on a scope without knowing what you want.

It is entirely possible that something would work as designed, but would not work for what you need. When you consider the sellers on eBay, that possibility becomes even more likely.

John
 

Supercap2F

Mar 22, 2014
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Thats not what I meant. I know that I want a oscilloscope with a bandwidth of 20MHz or higher and I know that I want one with 2 channels. I do not care if it has a CRT or LCD display or if it is digital or analog or if it is a bench top or a portable one. Ebay does not have a lot of the same type of oscilloscope on it so I can not be real picky.

All the best

Dan
 
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jpanhalt

Nov 12, 2013
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Have you looked into the cost of replacing a CRT?

My primary scope is a Tek 210 with LCD. I also have a couple analog scopes with CRT's. In fact, I got three of the analog CRT scopes (at decent prices), just to be sure I had spare parts.

20 MHz is reasonable. 60 or 100 MHz is better. I suggest an LCD, digital scope comparable to or better than the now quite old, TDS210.

I started with a Velleman portable 5 MHz scope (the current version is 10 MHz). It is still useful, because it is battery operated. The current generation of portable scopes shouldn't be ignored.

John
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Does it have probes? (can't test it without them)

If you're looking at a specific model, let us know what it is and how much they're asking.

As a rough rule of thumb, $1 for each MHz of bandwidth is generally a reasonable price unless it's something special (higher) or really poor condition (lower).

I have a 60MHz scope that cost me around $60, but for that price I had to find my own probes -- as a warning, my probes cost me almost as much as the meter (but they were nos HP probes).

If you get a scope, be warned that you have a piece of equipment that has huge potential as long as you learn how to use it. It's also relatively easy to damage if you make basic mistakes. If this is your first scope (I expect it is) then get the manual for it. Again, post the model number here and someone should be able to tell you where to download it, if one is available.
 

Supercap2F

Mar 22, 2014
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Jpanhalt: No I have not looked in to the cost of replacing a CRT is it a lot? The scope you have goes for about $300 on ebay which is well out of my price range. Do you know of any were else to get it?

(*steve*): I have got a probe. I was looking at a bk precision 2160 but there are no more on ebay. What kind of scope do you have? Where did you get it?

Thanks guys

Dan
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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I have a Philips PM3055. I got it from eBay. I paid under $50 for it, but freight cost as much again. The probes cost me around $60.

If you want a good buy you need to keep your eyes open and look for scopes that people may have missed.

The one I got was (in my opinion) an absolute steal. But it took me several months of looking, bidding, and losing before I got this one. And there's one on eBay now. (A bit more than I paid).

Honestly though, if you even think of paying more than a couple of hundred for a scope, you should weigh up the option of buying a new digital scope. There have been some advances in the last couple of years that mean you can get a lot of scope for very little (comparatively) money. Take a look at some of the Rigol scopes for example.
 
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