Author Topic: EEVblog #498 - How to get a $50 Oscilloscope on Ebay  (Read 60442 times)

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Offline c4757p

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #150 on: August 18, 2013, 11:44:56 am »
Yeah, those aren't bad probes IMHO. I currently have a pair of these. The cables aren't good - I've had them for about a year and a half now, and the conductors are beginning to be intermittent now. But everything else is great. Nice and flexible  ::) with a good feel, and they are thin and nimble and easy to maneuver around a board. Just don't expect them to be heirlooms :P

I actually have a full set (all four channels) of Tek P6137 probes, and unless I have a reason to need to trust the probes a bit more, I usually reach for my Wun Hung Lo's. (It takes so much force to plug in the Teks that I have to hold my scope still with my other hand... and the ground leads are not convenient.)
« Last Edit: August 18, 2013, 11:52:25 am by c4757p »
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Offline PaulAm

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #151 on: August 18, 2013, 12:46:07 pm »
See if you can find a pair of p6065a x10 probes.  They'll have the readout pin so the 465 will be able to light up the correct light on the attenuator.  Sometimes you can find them pretty cheap.

I've probably spent more on probes than on oscilloscopes though.

Be aware that the usable bandwidth with a x1 probe is not much more than 1 MHz or so.  There's an incredible amount of engineering that goes into them; they're a lot more than a piece of coax with a needle point on the end.
 

Offline amtpdb

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #152 on: August 18, 2013, 01:44:25 pm »
Thanks to everyone that responded.
I will go to ebay and see what is too be had. I guess any 100mhz probe will work considering your answers.
Thanks again.
Don
 

Online edavid

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #153 on: August 18, 2013, 02:35:15 pm »
See if you can find a pair of p6065a x10 probes.  They'll have the readout pin so the 465 will be able to light up the correct light on the attenuator.  Sometimes you can find them pretty cheap.

They are only 75MHz probes, so not the best choice for a 465.  Oops!

Quote
Be aware that the usable bandwidth with a x1 probe is not much more than 1 MHz or so.  There's an incredible amount of engineering that goes into them; they're a lot more than a piece of coax with a needle point on the end.

That's pessimistic... Tek P6028 is 17MHz, P6101 is 15MHz...
« Last Edit: August 22, 2013, 05:07:20 am by edavid »
 

alm

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #154 on: August 18, 2013, 11:13:40 pm »
From a 25 Ohm source that doesn't mind ~60 pF of capacitance on its output.
 

Offline Stonent

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #155 on: August 19, 2013, 02:15:41 pm »
Speaking of the $10 100MHz Ebay probes... Is it normal for probes to induct waveforms?  I found a week or so ago that when I passed the probe tip over a CPU a waveform appeared on the scope. Also got a fairly nice square wave by sticking the tip inside an inductor (that doesn't surprise me as much as the CPU)
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Offline KJDS

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #156 on: August 19, 2013, 05:42:44 pm »
Speaking of the $10 100MHz Ebay probes... Is it normal for probes to induct waveforms?  I found a week or so ago that when I passed the probe tip over a CPU a waveform appeared on the scope. Also got a fairly nice square wave by sticking the tip inside an inductor (that doesn't surprise me as much as the CPU)

That's very normal. The scope has a 1Mohm input impedance with a longish antenna hanging off the end.

Offline amtpdb

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #157 on: August 21, 2013, 10:43:20 am »
These are the ones I bought! Hope they work.
Thanks to everyone that answered.
Don

http://www.ebay.com/itm/230803653667?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
 

Offline Sigmoid

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #158 on: August 22, 2013, 01:31:27 am »
Ans then there is
- Lecroy lc574al ... (opens 400€) ... Seriously, I think it there must be some kind of caveat here?..

I'm a bit confused about these old, raster CRT digital scopes. I'm a computer engineer, and I'm quite used to digital equipment older than 5 years being synonymous with landfill. These old Lecroys seem to be ages old, in both effective years and in steps of technological advancement. And yet they command ridiculously high prices on eBay.
Are they worth anything? From what I gather, old DSOs are outclassed and outperformed even by the lowest end new ones in sampling rate, memory depth, and pretty much every other conceivable aspect - not to mention the obsolescence of the interfaces they use (floppy disks, lol, might as well be magnetic tape spools).
Is there any reason beside hype that anyone would pay close to $1000 for an ancient raster CRT digital Lecroy?
 

Offline marshallh

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #159 on: August 22, 2013, 04:00:58 am »
Ans then there is
- Lecroy lc574al ... (opens 400€) ... Seriously, I think it there must be some kind of caveat here?..

I'm a bit confused about these old, raster CRT digital scopes. I'm a computer engineer, and I'm quite used to digital equipment older than 5 years being synonymous with landfill. These old Lecroys seem to be ages old, in both effective years and in steps of technological advancement. And yet they command ridiculously high prices on eBay.
Are they worth anything? From what I gather, old DSOs are outclassed and outperformed even by the lowest end new ones in sampling rate, memory depth, and pretty much every other conceivable aspect - not to mention the obsolescence of the interfaces they use (floppy disks, lol, might as well be magnetic tape spools).
Is there any reason beside hype that anyone would pay close to $1000 for an ancient raster CRT digital Lecroy?

I would gladly pay $1k for one of the higher end 93xx series.
They may be a bit long in the tooth, but
1. Huge input bandwidth, you can take advantage of RIS
2. 50ohm input termination (for some reason the chinese scopes omit this entirely)
3. No freezing/crashing
4. No overclocked ADCs
And if you pay $1k and put in some effort, you will get a much more capable and versatile scope than whatever chinese flavor of the month is most popular.
Also you might laugh, but $10 got me a USB flppy drive and pack of  new 3.5" disks. So that ones pretty much not a problem.

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Offline PaulAm

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #160 on: August 22, 2013, 04:19:00 am »
Those probes should be fine.

I stand by what I said about the p6065a probes.  From the 1973 Tek catalog:

The P6065 is a miniature passive probe with precise 10X attenuation for use with the Tektronix 465 Oscilloscope. When used with the 465 Oscilloscope, the bandwidth will be 100 MHz. When compensated to other 20-24 pf input capacitance instruments the bandwidth will be at least 75 MHz.

 

Offline amtpdb

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #161 on: August 24, 2013, 01:58:26 pm »
OK the 465 scope arrived. Tried to get something on the screen. New probes and did get some kind of square trace. Vertical lines are very weak. Buttons are very sticky. One time I get some thing and work the nobs so as to work the contacts, then nothing, then something. The square trace has many lines working their way up to the horizontal one. I know the thing needs to have the contact switches cleaned. At least, can someone tell me what and how to clean the switches and rotary switches? That would be a big help. I have wanted one of these for some time, only used one in electronics class a few times years ago. Any help anyone can give will be greatly appreciated. I don't want to open this up blindly.
Thanks and have a nice day.
Don
 
 

Offline rf-loop

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #162 on: August 25, 2013, 07:41:05 pm »
You can find lot of information for 465.
But please, follow only these guys who know what they do.
This is one example.

Cleaning the Volts/Div Attenuator Switch Contacts in Tektronix 4XX Oscilloscopes

This is not propably best but just try find this kind of info.
Also use original Tek 465 service manual.
(many things depend also what version 465 you have.)

Never ever put any kind of lubricating (oil) liquids to these contacts becouse after then all collected dust stay there and inhibit good contact)  I mean contact surfaces. All contacs there are serviceable. (mostly after service/overhaul  they work as new)

Pure Isopropyl is just right. (also some other can use. Never ever try ethanol or methanol or some other "destroy" liquids for any use with these) Some good quality dry video cleaner is also ok, and in some places good quality "deoxit".

Then careful if your model is with unsoldered semiconductors assembled with socket. Some times they may drop. Do not turn any internal adjustement until know procedure.  Adjuxstment is described in service manual and there is also interactions between adjustments - some adjustments need do with right order. Some adjustments need special test equipments.

465 can use and adjust without external service fan when case is open. (most of 2400 need external fan - if want avoid hybrids damage.)
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 amtpdb

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #163 on: August 26, 2013, 04:17:53 am »
rf-loop:
Thanks for the information. I read the article and will attempt to do as indicated.
Thanks for your time.
Have a nice week ahead.
Don
 

Offline erick

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #164 on: October 22, 2013, 04:52:40 am »
Hey, guys

It finally happened. After about eight months looking for a decent used scope, I managed to find an engineer selling his old Tektronix 2215A (he went digital).

It cost me almost 200 dollars, but here it Brazil you won't get any better deal, especially considering it is a Tektronix oscilloscope, working just fine.

It came with just one old hitachi probe. I'm looking for another one on ebay, now, wondering if it's worth buying a good expensive one or if I should go with one of these cheap chinese probes.
 

Offline amtpdb

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #165 on: October 22, 2013, 08:04:30 am »
Well the scope I received had more problems then I first thought. I sent it back. So the final outcome of this was no scope and I had to pay to and from shipping that amounted to 100.00!!! That shows you my luck. I am again very hesitant to try this again!
 

Offline iXod

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #166 on: October 24, 2013, 05:17:34 am »
It's worth it ($0) to post an advert on the local CraigsList in the Electronics area and ask if anyone has one (even not working).

I got a "dead" Tek 2430A for $0 that just needed a new param battery.
 

Offline kc9qvl

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #167 on: November 15, 2013, 02:15:19 pm »
My  tds360 fresh out of the bath. $55.00 from craigslist. Good probes on order. Did a little mod. The small toggle switches next to the input jacks. Set the Tekprobe interface to 10x. That bit of goop around switch is exactly that GOOP. Bit of extra insurance hold the switch.
« Last Edit: November 15, 2013, 02:28:45 pm by kc9qvl »
 

Offline katzohki

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #168 on: February 18, 2014, 08:08:05 am »
For those living in or around the LA area in California, look up the W6TRW swap meet and go to it (every 4th Saturday around Marine/Aviation Ave I think). There are TONS of cheap oscilloscopes! This is where I got my first scope, it was an off brand LG 60MHz and I paid 40$!
 

Offline timelessbeing

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #169 on: February 18, 2014, 02:04:23 pm »
Is Instek any good?
 

Offline katzohki

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #170 on: February 18, 2014, 02:48:46 pm »
Is Instek any good?

They're not bad in my opinion. Did you find one for less than 50$? Dave did a review on one recent model.
 

Offline timelessbeing

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #171 on: February 18, 2014, 04:12:35 pm »
Nope. Both over $100.
 

Offline EEVblog

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #172 on: February 18, 2014, 06:02:57 pm »
Is Instek any good?

Instek (GW/Goodwill) are a name brand, and have always made pretty decent stuff.
 

Online edavid

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #173 on: February 19, 2014, 03:58:22 am »
Is Instek any good?

It can be hard to find service manuals  :(
 

Offline timelessbeing

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Re: EEVblog #498 - How to get a $50 Oscilloscope on Ebay
« Reply #174 on: February 19, 2014, 09:23:33 am »
Cool. I'll add GW/Instek to my list of candidates.
 


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