Trouble on Deciding How and Where to Get a Oscilloscope!!!

[MistaMun]

Hello!

I am working on a 3D printer that foolishly decided to do... Got my adruino mega and etc but came across some fundamental problems and decided to get an oscilloscope for troubleshooting.

On couple of videos, Dave said it was "easy" to find some cheap under $50 analog oscilloscopes on eBay, which I had basically no luck on finding. I guess I am just not compatible with eBay...

There are just too many types, companies, specs, and other things that I am not just aware of and what should base it as standard for my quest for my first oscilloscope

I do not really know what things like sample rates and etc but I know that it gets much more expensive as those numbers rises.
Many people have told me that 20Mhz is pretty adequete but is it?

I have been looking through pocket DSO and usb-pc based oscilloscopes but Dave has also did some "rants" against those kinds of oscilloscopes...

As a highschool student on low budget, can anyone in the community advise me on what I should do and get for my first oscilloscope?

A big thanks beforehand! 

[theatrus]

First off, what are you debugging? If you're touching digital signals only, a pure analog scope can be frustrating as it cannot store and display a one time event. In this case, a simple logic analyzer might be ideal, as a digital storage scope would be harder in the $50 price bracket.

[MistaMun]

First off, what are you debugging? If you're touching digital signals only, a pure analog scope can be frustrating as it cannot store and display a one time event. In this case, a simple logic analyzer might be ideal, as a digital storage scope would be harder in the $50 price bracket.

Nothing major. Forgot to put that I was also getting it for educational usage, to learn and stuff. Well, I have optical linear encoders that I got out of printer heads and want to see if they actually give out the correct signal as the linear encoder strip moves across them. For some reason, it will only increment one way and not the other way as I change the direction. I thought the timing was right where I am extending the knowledge of different test equipment such as oscilloscopes, which I have been looking through for couple of months

[Shock]

I just went on ebay and found several buy now under $50.

[edy]

 I bought 2 scopes off eBay, with all shipping in, one for $50 (20 mhz dual channel CRO) and $85 (100 Mhz dual channel CRO with on-screen cursors). You can do it but you need to set up autobid and just let them ride. Eventually you will land one. Even if the price is well below, just set your autobid to $50. You will not pay $50 unless it gets bid up to that amount, and you can reject raising the limit higher so you can get out easily. Eventually out of luck and timing you can find these deals.

I also have a small cheap digital scope (xprotolab) which is cute and fun to play with but is limited mostly to audio frequency ranges. I use it mostly for the AWG and logic analyzer features, plus it can interface with your PC for saving more data.

[MistaMun]

I bought 2 scopes off eBay, with all shipping in, one for $50 (20 mhz dual channel CRO) and $85 (100 Mhz dual channel CRO with on-screen cursors). You can do it but you need to set up autobid and just let them ride. Eventually you will land one. Even if the price is well below, just set your autobid to $50. You will not pay $50 unless it gets bid up to that amount, and you can reject raising the limit higher so you can get out easily. Eventually out of luck and timing you can find these deals.

I also have a small cheap digital scope (xprotolab) which is cute and fun to play with but is limited mostly to audio frequency ranges. I use it mostly for the AWG and logic analyzer features, plus it can interface with your PC for saving more data.

Thanks for the insight! But I still had no luck on auto bidding or anything... I been looking through the buy now on lowest prices settings but still no luck. Maybe if anyone in the community have any good posting that they can share? People say that they have find plenty and its everywhere and etc but I need to see it wit hmy own eyes    

[Rasz]

find hams in your area, ask for old gear, receive cookie.

[edy]

First major question is where are you located? I'm in Canada and could find gear in my area but I found a better selection with cheaper options south of the border so I had them shipped to family who brought them up.

[MistaMun]

I currently live in VA and the closest major city I live near is Washington D.C. which is around 40 minutes away. I actually asked someone who bought an oscilloscope recently told me that there are more much more poeple who are willing to sell their old scopes much cheaper and in better condition in the west because majority of the people who are retiring are mostly present there.

Day 13: Still have not seen any signs of usable oscilloscopes under $50 everywhere....

[MistaMun]

How about this tiny oscilloscope? :0 I feel like it fits my needs of troubleshooting minor electronic projects in Arduino!
http://www.gabotronics.com/oscilloscopes/xprotolab-plain.htm

There are versions with and without the buttons and the display but for money's sake, I am planning to go with the one that is bare bones.

Its not some kind of One hung low thing from china but it seems to me that it is genuine made to last product to me from what I have been researching!

[theatrus]

2MSPS and 200kHz BW (if that). Its not even particularly useful for any low speed digital bus.

[vk6zgo]

I currently live in VA and the closest major city I live near is Washington D.C. which is around 40 minutes away. I actually asked someone who bought an oscilloscope recently told me that there are more much more poeple who are willing to sell their old scopes much cheaper and in better condition in the west because majority of the people who are retiring are mostly present there.

Day 13: Still have not seen any signs of usable oscilloscopes under $50 everywhere....

Look for "Hamfests" in your area.

Your Nation's Capital will probably have many "Hams",so you may well pick up a cheap 'scope.
Don't neglect to check in your hometown,too!

Hamfests,of course,are mainly about Radio equipment,but I have found that there are usually several sellers with test equipment.
Hams are usually very approachable,so even if they don't have what you need,they may be able to put you in touch with someone who does .

[Jebnor]

Check Craigslist ( or equivalent in your area.)  I picked up a TEX 547 4CH for $25.   Admittedly I got luck, but, don't forget the classifieds.

[Rigby]

Just keep your eyes open.  You're either going to invest a lot of time looking or a lot of money buying.

[David Hess]

Check Craigslist ( or equivalent in your area.)  I picked up a TEX 547 4CH for $25.   Admittedly I got luck, but, don't forget the classifieds.

I would consider a 547 high end even now.

Plus you can use it to crush your enemies.

[simpson]

My opinions:

Though I recently bought my first scope locally, I still search eBay for bargains and I do find quite a few there.

Go to eBay's Advanced Search page and set up your search for scopes that are within, say, 500 miles of your zip. This will bring up all the scopes that are relatively close to you. Then, those sellers in your area that use calculated shipping will therefore have relatively low shipping costs. I do this all the time and see shipping costs for analog scopes as low as $12. Not all of them will be this low, of course, but some of them will. Shipping costs <= $20 are not hard to find this way. This cuts your cost down a lot.

But, don't buy a scope unless you are reasonably sure it is in good working condition. On eBay "untested" usually means "broken" and buying a broken scope is just a waste of money. If uncertain make sure you can at least return it (though you will have to pay return shipping costs).

Before bidding look up the scope on Google and see if you can find a manual for it (if not included in auction) and if anyone has any comments about it.

Don't worry too much about getting a super-dooper scope. You probably won't get a mint 200mhz Tektronix for 50 bucks on eBay. Just get a scope that works and you will learn a lot using it. Later on you'll probably get a better scope anyway.

[vk6zgo]

Check Craigslist ( or equivalent in your area.)  I picked up a TEX 547 4CH for $25.   Admittedly I got luck, but, don't forget the classifieds.

I would consider a 547 high end even now.

Plus you can use it to crush your enemies.

And it keeps you warm on those long winter evenings!

[sunnyhighway]

I once asked my nephew who is photography enthousiast with a lot of fancy and expensive equipment: "What camera I should buy and why it is the best"

His answer surprised me, as I was expecting something in the line of a 2000$ high-end Canon camera or the likes.

Instead, his answer was:

"The best camera is the working one which is right there whenever you feel like taking a picture. For me that's usually this one."
<This is where he showed me his ancient Nokia 225 feature-phone which sports a lousy 2 megapixel camera>

It took me a couple of seconds to let the implications were of what het just said sink in.
Then I realized it absolutely makes sense what he just said

I guess the same goes for a scope.
It's not the 5000$ fancy scope (which you store under a nice protective cover, disconnected from mains, to keep it in mint condition) you will use the most.
It's the dirt cheap one you have sitting on your bench you will be using most.

[David Hess]

Check Craigslist ( or equivalent in your area.)  I picked up a TEX 547 4CH for $25.   Admittedly I got luck, but, don't forget the classifieds.

I would consider a 547 high end even now.

Plus you can use it to crush your enemies.

And it keeps you warm on those long winter evenings!

I have a 545 for that.

[EEVblog]

On couple of videos, Dave said it was "easy" to find some cheap under $50 analog oscilloscopes on eBay

Some countries and regions are easier than others.

I do not really know what things like sample rates and etc but I know that it gets much more expensive as those numbers rises.
Many people have told me that 20Mhz is pretty adequete but is it?

A 20MHz dual trace oscilloscope is still a very powerful instrument. 20MHz was the entry level standard for several decades, and not a huge amount has changed these days, it's still just as useful.

I have been looking through pocket DSO and usb-pc based oscilloscopes but Dave has also did some "rants" against those kinds of oscilloscopes...

The pocket DSO's are just toys.
Better than nothing, but I argue a 20MHz analog is vastly better.

[SeanB]

I once asked my nephew who is photography enthousiast with a lot of fancy and expensive equipment: "What camera I should buy and why it is the best"

His answer surprised me, as I was expecting something in the line of a 2000$ high-end Canon camera or the likes.

Instead, his answer was:

"The best camera is the working one which is right there whenever you feel like taking a picture. For me that's usually this one."
<This is where he showed me his ancient Nokia 225 feature-phone which sports a lousy 2 megapixel camera>

It took me a couple of seconds to let the implications were of what het just said sink in.
Then I realized it absolutely makes sense what he just said

I guess the same goes for a scope.
It's not the 5000$ fancy scope (which you store under a nice protective cover, disconnected from mains, to keep it in mint condition) you will use the most.
It's the dirt cheap one you have sitting on your bench you will be using most.

Plus 1000 for that one. I have a lot of photos taken with the closest camera, often a cellphone camera. As the camera in the phone has improved with each model iteration so the pictures have improved. I have even used my video camera as a still camera, just because it is both handy and gives a very good image that is good enough for web use. Even the cheap Genius DVR in the car has given useful video and still images, even though it is by no means the best camera, it is the one that is always in the car and running when driving.

[Galaxyrise]

I suspect the aforementioned $50 does not include shipping or probes.  Expect your final bill to come out to closer to $100 all said and done, unless you get very lucky or find one you can pick up "locally".  An analog oscilloscope is big, heavy, and delicate--costs a lot for a private individual to ship.

[edy]

Someone in the thread already suggested this... I agree... use Advanced search and look for sellers within your driving distance. Look to see if they are available for "local pickup" or ask to come by and view equipment. You may be able to save on shipping.

Someone else mentioned that on ebay the CRO (cathode ray oscilloscopes) may be unreliable or if they aren't EXPLICITLY said to work, that they are broken. I would have to argue with that one...

There are a big chunk of scopes being sold by clearing-houses or government or educational institution auctions, surplus outfits and so on. They are not by private individuals who have been using their scope for years and can show you a working trace (Although it is a nice photo to have on the item).  Usually these places buy truck-loads of gear and sort them out. They don't have time or resources to test them all... They just want to flip them and make a fast buck.

Out of the 2 scopes I bought off eBay, the $50 one (all in, shipping included to New Jersey where my parents then drove it up to me in Canada) was from a private individual in Florida. It came in a nice box with manuals and everything. Good condition, 20 Mhz scope and a trace and the owner confirmed it was working. He sent me some probes too. It was one of those Hung-Chang models that had 30 names.... See thread here:

https://www.eevblog.com/forum/testgear/my-$50-scope-seems-doa-tenma-72-720/

Also you will notice in the thread above that the forum member thought his scope was D.O.A. but after playing with the knobs a bit, he got it to work. Same thing happened to me with my scopes... so it is easy to think a scope is dead when it is not.

The second scope I bought off eBay was the $85 one (also all in shipping to New Jersey from somewhere in the USA) was from an Auction-Surplus-Clearing-House type outfit. It was a Hitachi 100Mhz with on-screen cursors and much more advanced than the $50 20 Mhz scope. The listing didn't show a working trace, and there was some cosmetic damage (missing handle) and it looked a bit beaten up. The pictures were fuzzy and quite a few people passed on it (even one member from the EEVBlog forums who happened to also be watching it told me later)!!! Anyways, I ended up grabbing it and made some videos of it in action. It is quite a beastie and I am happy I picked it up.

Here is the relevant thread:

https://www.eevblog.com/forum/testgear/losing-my-'scope-virginity'-to-hitachi-v-1565-oscilloscope-100mhz/

I also contacted the seller by email and a lady from the Auction-clearance-house replied she doesn't know if they work or not. They don't turn them on. I also asked if they would be kind enough to throw in some probes and the packaged arrived with PROBES! So sometimes if you ask they will throw them in.

I think Dave also mentioned that he found lots of gear that works. However, you DO take a RISK, that is true. It is up to you to decide... But I don't think as many scopes are truly "broken", it is just people don't know how to use them or they pass through these clearing-houses and they just want to sell them and make a quick buck. At least ask the seller if it powers on, if there is a light, or a trace. Sometimes they just have the knob turned all the way over or the brightness down. Simple things that a lay-person selling surplus isn't going to necessarily test if they have hundreds of pieces of equipment.

Also regarding the cheap little scopes like XProtolab by Gabotronics... I have one. It is a fun thing to plug into a breadboard and play with, or generate signals or sniff data packets.... you can also hook up to PC for capture. But it is just not comparable to a CRO. It is like Apples and Oranges..... I wouldn't even try to consider one an alternative to the other. If you want something like that, check out the Gabotronics Oscillope Watch based on the XProtolab. You can have a lot of fun with it, but it is not a replacement for a CRO.

[David Hess]

Someone else mentioned that on ebay the CRO (cathode ray oscilloscopes) may be unreliable or if they aren't EXPLICITLY said to work, that they are broken. I would have to argue with that one...

And they may still have subtle or even gross problems.  Shipping is an issue as well and half of the large mainframe oscilloscopes I have bought were damaged by UPS.

[edy]

Yes good point! The shipper must package them very well. I have been lucky, they arrived in very solid boxes with lots and lots and lots of padding. Essentially you take the risk with ANY item delivered by postage. Unless you go to a local shop or buy from an individual person or HAM club from Kijiji or Craigslist... and see one working for yourself and take it home yourself, you will always have a risk of damage. Especially true on older equipment that usually has no original box and must be packed in something it wasn't designed for, with crusty old brittle components.... and heavy equipment like CROs.

So you have to decide whether you want to risk $25-75 on an eBay scope, or just pay $150-200 for something locally available that you know is working and can verify it yourself.... That is the risk you take. But if you are already paying $150-200 for a CRO, then an entry-level DSO starts to be attractive as well... they are maybe $250-300? You can buy some new or used Owon, Atten, Protek and even Rigol for cheap.

If the OP is adventurous, they can risk buying off eBay, just make sure before you bid on anything that the full schematics are available. Then if there is a problem, you may be able to fix it. You bought a scope to learn more about electronics? So now you have your first project... fix a broken scope. :-) Seriously though, you *CAN* buy a working scope for $50 from eBay or Craigslist or Kijiji but you have to be patient... I waited several months and missed buying about 3 scopes in that time which I had my heart set on.... all of which some other people grabbed for around $50. Just look at the selling history and you will see scopes that end auction around those prices.