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Old 23rd July 2008, 07:29 PM   (permalink)
Default does this look like a good oscilloscope??

cgi.ebay.com/Tektronix-475-Oscilloscope-Scope_W0QQitemZ180266417572QQihZ008QQcategoryZ1042 47QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Anyone have any they would recommend from ebay $150 and under?

Last edited by Qaiphyx; 23rd July 2008 at 07:32 PM.
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Old 23rd July 2008, 07:44 PM   (permalink)
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I don't know much about scope models but there is a useful guide about buying them on ebay.
http://reviews.ebay.com/Buying-an-Os...00000001568756

It describes the various Tek models including the 475 which it says is good apart from the TAS prefix versions.
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Old 23rd July 2008, 09:11 PM   (permalink)
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If the dollar wasn't in the crapper, then the smallest Picoscope would be and option too, but it is too expensive now at $250.
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Old 23rd July 2008, 09:30 PM   (permalink)
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Do any of the scopes for sale on E-Bay actually work properly??
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Old 24th July 2008, 04:33 AM   (permalink)
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The one I bought for 30 bucks (including shipping) still serves me fine.
The one Qaiphyx linked looks like a good deal for about 100 bucks total. 200mhz dual channel the seller has a good feedback rateing and claims the unit works fine with a screen capture that shows a trace. If it's through paypal it's a very safe bet. I'd go as high as 150-200 I think. It's a 200mhz scope, and analog, Picoscope has nothing on that. Only bad part is no probes, so you're either stuck in the DC and low AC realm or you're going to have to build or buy probes.
If I could spare the money I'd bid myself.
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Last edited by Sceadwian; 24th July 2008 at 04:36 AM.
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Old 24th July 2008, 04:45 AM   (permalink)
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Tektronix makes very good scopes. But if it breaks there is a manual online for it.
http://bama.edebris.com/manuals/tek/475/
The 465B is also a very good scope and, though it is a 100Mhz unit, they typically are good to 150Mhz or so. Note that the scope doesn't come with probes. Working probes can be pricey, so check that out also.
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Last edited by kchriste; 24th July 2008 at 04:50 AM.
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Old 24th July 2008, 05:18 AM   (permalink)
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New probes alone are $150. And that's for the cheap passive types.
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Old 24th July 2008, 04:17 PM   (permalink)
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It is considered a very good scope, but remember it may be more than 30 years old. There are things that age like capacitors and switch contacts, etc, that may need attention.

My Tek 2235 is from the '80s and another scope I had was entirely tube based, from the '60s and I only retired it about 4 years ago. So age is not a reason to walk away.
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Old 26th July 2008, 01:30 AM   (permalink)
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"The 465B is also a very good scope and, though it is a 100Mhz unit, they typically are good to 150Mhz or so."

That's a bit of a misleading statement. The specified bandwidth of the 465, 465M or 465B is 100MHz. Being "typically good to 150MHz or so" does not mean that they will be amplitude-accurate. Most 465s will have their 3dB bandwidth point over 100MHz, but not as high as 150MHz .... maybe more like 105 or 110MHz. Any higher, and the amplitude measurement will not be correct at all. Even at 100MHz, a barely-in-spec instrument will have an amplitude error of -3dB. A 465 is "good" to a lot higher than 150MHz. It will still trigger at those higher frequencies, still display the waveforms (fast-rise pulses will not appear as fast as they really are and amplitudes will be lower than they actually are) and you will still be able to use them to measure frequencies, although the 5nS/sec you can get at the 0.05µS TIME/DIV setting with the 10X horizontal magnifier on may not be fast enough to separate individual cycles for easy measurement.

Dean
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Old 26th July 2008, 07:27 PM   (permalink)
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Quote:
Originally Posted by speakerguy79 View Post
New probes alone are $150. And that's for the cheap passive types.
Perhaps you should shop around a bit. Cheap passive probes are typically $25 to $50. Here's an example:

http://search.digikey.com/scripts/Dk...me=290-1002-ND

I use Tek, HP and after-market probes such as these and find that as long as I'm the only one using them, they all last a long time. In a commercial setting, with many users, I would purchase Tek or HP only as they don't fall apart under heavy use.
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Old 26th July 2008, 11:50 PM   (permalink)
Angry Gassy CRT

Quote:
Originally Posted by Qaiphyx View Post
cgi.ebay.com/Tektronix-475-Oscilloscope-Scope_W0QQitemZ180266417572QQihZ008QQcategoryZ1042 47QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Anyone have any they would recommend from ebay $150 and under?
The problem with buying such an old scope is a defect that is not is much talked about, namely gassy CRTs.
This is usually not a problem for viewing repetitive waveforms but when you have to turn the brightness up to view and trigger a single pulse the brightness is not there. As a matter of fact the easiest way to find this problem is to closely watch the trace as you increase the brightness, if it increases and then decreases as you turn the knob clockwise then the CRT is gassy,. You also see a focus change..
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