is it worth to buy an old non working oscilloscope?

[RawCode]

Hi there!
I'm an italian electronic engineer student. i'm beginning my last year before the bachelor degree(i'm going to study until full degree), and this year we are going to labs! Horray! but i have a question. Do I need an oscilloscope? will i use it in the future? They are pretty expensive for my pocket as a student. Some years ago I bought a kit oscilloscope, with a poor bandwith of 20kHz, but I don't have the "need" of use it, maybe because I'm studying serious electronics right this year, but i don't know.

So, inspired by the eevblog's video to hunt cheap analog oscilloscope on ebay, i find one only cheap analog oscilloscope, an Hameg 203-7 with a problem (damn). The seller says that it shows the trace, but the inputs doesn't works. I don't know the severity of the problem, but is an auction and if i win it, it would cost around 30/40 euros. What do you suggest? Is it a easy solving problem?

peace

[Electro Detective]

If you want to be a successful student by not wasting time trying to fix someone else's oscilloscope problem     THEY could not fix    

do not buy a non working oscilloscope   

You will finish your student course/degree in good health and ALIVE too, by not getting zapped by the oscilloscope power supply trying to fix it (IF it is fixable and parts available)

Your multimeter will thank you too 

and your family and friends won't have to visit you in hospital
or buy flowers for worst case scenario   

[kripton2035]

for 50 euros you can get a working one, if you're patient. If it was free, ok for a non working analog scope.
don't forget as a student if you ask, lots of university get rid of their old devices regularly.
ask kindly your professors about it there are certainly some deal to make.
you will also proove you're interested in your studies, something that seems lost nowadays...

[RawCode]

Thank you guys, i appreciate your suggestions 

[Rbastler]

Dont buy a broken oscilloscope as a first time scope. Repairing can be potentially fatal, if you dont know what youre doing and youll need a oscilloscope anyway to repair another one some time.
I agree asking your professors. Some are really happy and help you, if you ask kindly and show interest.

I assume its this auction ? http://www.ebay.it/itm/Oscilloscopio-usato-/202070083923?hash=item2f0c50c953:g:eksAAOSwnyBZ0KQM

But this could be a bargain: http://www.ebay.it/itm/Fluke-Philips-Pm-97-Oscilloscopio-Spettro-Radiotecnico-Multimetro-/302473435115?hash=item466cd257eb:g:D2kAAOSwOKVZ0TV8

Edit: I found that on ebay.it its rather difficult to find scopes, or other equipment. So 50€ for something working could be quite difficult. Ebay.de is better in that regard.

[RawCode]

Dont buy a broken oscilloscope as a first time scope. Repairing can be potentially fatal, if you dont know what youre doing and youll need a oscilloscope anyway to repair another one some time.
I agree asking your professors. Some are really happy and help you, if you ask kindly and show interest.

I assume its this auction ? http://www.ebay.it/itm/Oscilloscopio-usato-/202070083923?hash=item2f0c50c953:g:eksAAOSwnyBZ0KQM

But this could be a bargain: http://www.ebay.it/itm/Fluke-Philips-Pm-97-Oscilloscopio-Spettro-Radiotecnico-Multimetro-/302473435115?hash=item466cd257eb:g:D2kAAOSwOKVZ0TV8

Edit: I found that on ebay.it its rather difficult to find scopes, or other equipment. So 50€ for something working could be quite difficult. Ebay.de is better in that regard.

yes, is that auction.
Thank you for the suggestion, i'm going to evaluate this oscilloscope I'm also going to ask to my professor if he knows where i can find some cheap oscilloscope

[kripton2035]

don't know where you are in italy, but in south of france, there are some working hameg for 30 euros ready to pickup ...
https://www.leboncoin.fr/annonces/offres/provence_alpes_cote_d_azur/?th=1&q=oscilloscope

[RawCode]

don't know where you are in italy, but in south of france, there are some working hameg for 30 euros ready to pickup ...
https://www.leboncoin.fr/annonces/offres/provence_alpes_cote_d_azur/?th=1&q=oscilloscope

Thanks, i've just sent a message to him to ask if he ships to italy.

[rstofer]

If I were a student, I would be looking at Digilent's Analog Discovery as a very handy toolbox.  It has a dual channel scope, dual channel arbitrary waveform generator, network analyzer, logic analyzer, and a bunch of other essential pieces.

http://store.digilentinc.com/analog-discovery-2-100msps-usb-oscilloscope-logic-analyzer-and-variable-power-supply/

The idea that I could carry my lab in my backpack is pretty compelling.

There is a significant student discount available but I don't know how much it is.

Download the free Waveforms software and play with the demo mode.  It's a pretty amazing tool.

[kripton2035]

yes it's a nice device, but shipping to europe is $51 ...

[phil]

There are distributors in europe, too. There is even one in Italy:
https://www.mirifica.it/100270/digilent/410-321

[kripton2035]

still 150€ + shipping, even at academic price. not the price the OP first post .
but yes it's a nice device, better than a 30 years old hameg analog scope !

[rstofer]

yes it's a nice device, but shipping to europe is $51 ...

Doesn't Digilent have an office in Romania?
https://store.digilentinc.com/pages.php?pageid=26

I don't know if they handle direct sales from that office.

[rstofer]

And once you have the scope issue resolved, along comes a need for a signal generator, what about a power supply (albeit limited), logic analyzer or the ever handy network analyzer?

I don't use the AD2 every day but when it fits my needs, it works like no other tool on my bench.  I really like making Bode' plots (as an exercise) - they were a major PITA back in the '70s when I was in college.  Now I can just breadboard the circuit and let the AD2 display the plot.  Very cool!

For a student on a budget, there simply is nothing like it.  It does have to be used with care to not exceed its voltage limits but that shouldn't be a problem.  The fact that both scope channels are differential (if you don't use the BNC adapter board) is extremely useful.  Ordinary scopes just can't do this because the scope probe is grounded on one side.  If you need this capability, there are differential probes available but they cost more than the scope!  Or, you can tie up two channels with an A-B math function.  That's fine if you have enough channels...

[oldway]

Of course, I agree, do not buy a non working oscilloscope !

If you look after a cheap Hameg oscilloscopes, do not forget the HM412.....
They are good basic analog oscilloscopes....often, they only need a little contact cleaner to work like a new one....

I think the best Hameg analog oscilloscope is the HM605.

[Karlo_Moharic]

For 30/40 euros go for it , usually it's a simple fix like a blown capacitor or voltage regulator. Even if you don't fix it you will still learn something

[0xdeadbeef]

For 30/40 euros go for it , usually it's a simple fix like a blown capacitor or voltage regulator. Even if you don't fix it you will still learn something

Nah, if the inputs aren't working, chances are that someone shot the input stage e.g. by applying a too high voltage in 50Ohm mode.
The damage could be major. Trying to repair this as 1st electronic project is most probably a bad idea.

[tggzzz]

While at university, concentrate on doing those things that are best done at university; leave other things until outside university (e.g. during holidays or after graduating). Hence study and get good exam results.

As a very rough rule of thumb, technicians fix equipment, whereas engineers use equipment to develop new products. Both are valuable; which do you want to be?

Having said that, fixing equipment can help you understand the theory of how it works and also the practical difficulties of making something that implements the theory. That can be valuable.

If your current objective is to poke around in circuits, either get a working scope or use the universities' scopes.

If you decide to repair a scope, be prepared to find you can't repair it.

[bd139]

A broken oscilloscope is a whole EE education. It’s a combination of reverse engineering, understanding the signal processing chain and practical skills. . Really you can learn a lot about impedance, high frequency design,, frequency compensation, differential amplifiers, Schmitt triggers, power supplies, High voltage safety and  even a bit of physics with a dead one. Not to mention an education on construction and production of an actual device including mechanical considerations.

Problem is you usually need a working one to fix it. Buy a working one then a dead one.

Reverse and forward engineering are both important. The skills you learn above will help you when you jump into an actual job and get a turd on your plate. A lot of people just start again because they can’t reverse engineer and document something.

[adras]

I have no idea what I'm talking about, but especially in old devices the parts which fail are leaking/old capacitors. I've seen quite some cases where the fix was just to replace the broken capacitors. In some cases it's obvious which are broken, in others you need to unsolder and test them. That's also something which basically everybody can do.

There was one repair video from Dave where he had the original manual, which also included detailed trouble shooting information. That was awesome, you saw at which testing points which values were expected, and which fault it is if the voltage is wrong. I think that's also something everybody with a multimeter and soldering skills can do. But it's hard to get such a manual I think.

I guess all the other things which can go wrong require a very sophisticated knowledge where you start to reverse engineer the circuits. Reverse engineering also requires you to read every single datasheet of every IC which is used so it's very, very time intense. And if you have that kind of knowledge you can earn hundreds of dollars in an hour, so it's not worth the time to fix something that cheap. Unless you just want to tinker around.

But unless you're using spare money I agree with the others, get a working one. As soon as you've got your degree and a Job you should earn enough money to just give it a try without loosing a lot.

[tggzzz]

I have no idea what I'm talking about,...
I guess all the other things which can go wrong require a very sophisticated knowledge where you start to reverse engineer the circuits. Reverse engineering also requires you to read every single datasheet of every IC which is used so it's very, very time intense. And if you have that kind of knowledge you can earn hundreds of dollars in an hour, so it's not worth the time to fix something that cheap. Unless you just want to tinker around.

Thanks for responsibly including the caveat! I agree with your conclusions, unsurprisingly.

However, these things can often be fixed without understanding every IC's datasheets. Unlike designing a circuit, when faultfinding a circuit you can usually adequately guess each IC's parameters without needing a datasheet - especially op amps.

You must, however, have a good schematic down to the component level - where "component level" is defined as the level at which components can be replaced. For old HP/Tektronix scopes, that is transistor/resistor/capacitor/IC, and that is one reason they remain popular. For more modern equipment, it is the board level.

[NivagSwerdna]

Hi there!
I'm an italian electronic engineer student. i'm beginning my last year before the bachelor degree(i'm going to study until full degree), and this year we are going to labs! Horray! but i have a question. Do I need an oscilloscope? will i use it in the future? They are pretty expensive for my pocket as a student. Some years ago I bought a kit oscilloscope, with a poor bandwith of 20kHz, but I don't have the "need" of use it, maybe because I'm studying serious electronics right this year, but i don't know.

So, inspired by the eevblog's video to hunt cheap analog oscilloscope on ebay, i find one only cheap analog oscilloscope, an Hameg 203-7 with a problem (damn). The seller says that it shows the trace, but the inputs doesn't works. I don't know the severity of the problem, but is an auction and if i win it, it would cost around 30/40 euros. What do you suggest? Is it a easy solving problem?

peace

My 2p worth....
Unless your school is under-equipped you don't need one so defer the purchase.
In my experience second hand test equipment that doesn't work probably REALLY doesn't work since the person selling it often has the skills to fix simple problems so you will get something that is either hard to fix or unfixable... either way a huge waste of time.  There are exceptions, especially related to test equipment that nobody wants [must dig out my recently purchased HP interferometer counter one day  ] but it's a minefield.

IMHO.... Save up for a Rigol 1054Z instead or whatever is current when you actually need one.

[james_s]

I've had a lot of enjoyment fixing older oscilloscopes and other equipment but if you're looking for a first scope, buy one that already works. Chances are you'll need it to fix a broken scope you might pick up later. It's a bit of a gamble but you can save a lot of money buying broken equipment and fixing it but you don't always win. Sometimes you open the thing up and the damage is beyond repair.

[bd139]

You win regularly.  I just won. 200MHz Tek 475 with DM44 module for £30. One duff tant that took me 30 minutes to trace out and replace.

[Old Printer]

I would also recommend looking into the Analog Discovery 2. I have had mine about a month and am very impressed with it. It is a learning tool, and as such there are limits to it's capabilities - like bandwidth. It has a wide variety of electronics tools for both analog and digital signals. If it's specs are within what you need it is surely worth a look. If you don't know the specs of what you need, it might be premature to buy a scope at this point. As for the analog vs digital scope argument, both have certain signals they are best looking at. I have two older Tektronix analog scopes that both work well, but the digital scope in the AD2 allows me to study very slow signals better than an analog, not to mention taking snapshots of certain signals. Look on YouTube. Tomtektest in particular has some very in-depth studies using the AD2, and Derek Molloy also gives it a pretty clear demo. For learning it is a great tool. Dave