buying a oscilloscoop

[scroeffie]

hi iam looking to buy a oscilloscoop but i have no idea what to buy i dont want to go over 250 euros
iam not shure if i need only 2 channels or 4 ?
i only work on c64 computers spectrums  videogame consoles and crt monitors some tube radios /old amps and retro computers like 286/486 etc
thanks for helping ,oh and i never used one so i dont know anything about it

wanted to add. i got a free ibm crt monitor from a friend , he found it in the trash got it working almost perfect
psu is acting wierd sometimes it wont start up and when it does the first 3 min it turns off and on by it self
it has been fully recapped and cleaned and reflowed

[drdm]

I in my opinion:
2 Channels is good enough for repairing stuff, but the moment you want to do some more serious design work, you are gonna need 4 channels. A simple comparator can take up 3 channels if you drive the two inputs and want to see what's on the output. For your budget, however I thing you can only get a simple 2 channel USB scope with some limited features:
https://www.batronix.com/shop/oscilloscopes/PicoScope-2205A.html
If you are willing to spend some more money however you cant go wrong with the king of entry-level scopes:
https://www.batronix.com/shop/oscilloscopes/Rigol-DS1054Z.html
That, of course are brand new ones. If you have some patience and luck you may find something second hand.
 

[Wallace Gasiewicz]

Look at the o scope tutorial at the top of this forum, when you get through it you will know what you need.   

drdm is correct. For most repairs 2 channels is plenty. I very seldom even use two in repairing radios and audio stuff.   
I used to be a fan of old CRT scopes but they are getting old and usually require repair.  The older digital scopes are not great, newer ones are much better.  When you have done more research, perhaps others can help with their experience with newer digital scopes. There are a lot of reviews in the Test Equip Forum. 

When you need to analyze many channels it is frequently when you are looking at logic circuits.

Some scopes have logic analyzers built in but...If you need to analyze logic outputs there are relatively inexpensive logic analyzers available, these can show you many more channels.

[bborisov567]

You can look at the Hantek DSO2C15, it is a good entry level scope, there is also a version with built in signal generator if you don't have one. There are plenty reviews on Youtube and topics here on the forum.

[Gyro]

When the computers and video games that you are talking about were designed, 2 channel scopes were the norm in design labs. 4 channel scopes were very expensive (eg. Tek mainframes). People also knew how to use the external trigger input on 2 channel scopes when necessary. That's not to say that a 4 channel scope isn't highly desireable, but it's not an essential. This might make your limited budget stretch further.

Another item that was very expensive back then was the Logic Analyser. These day, you can get a basic Saleae USB logic analyser clone (which works with open source Sigrok) for <$10 for the 8 bit version. Back when everything was external to the microprocessor, wider LAs were used, typically 24 bits or so. 16 bit Saleae clones or even 32 bit USB models are also pretty cheap now. The work methodology was scope to look at signal integrity/quality, setup and hold timings etc, and the LA for decoding busses and decodes. SPI, I2C etc, weren't a thing back then, so protocol decoding is less useful.

I would factor both into your budget, that might mean spending a little less on the scope, but I think you will find the combination helpful.

[Aldo22]

@scroeffie: In your price range there is only one (new) benchtop scope with 4 channels afaik. The Hanmatek DOS1104
https://de.aliexpress.com/item/1005006329135606.html

I have no idea how good or bad it is. There don't seem to be any useful reviews on the web.

Other than that, under €250, almost the only one worth mentioning is the Hantek.
I would take the simplest model DSO2C10 at the cheapest price.
e.g. here: https://de.aliexpress.com/item/1005006809075280.html

Seriously better benchtop scopes are only available from about 400 € upwards.

There are of course other types, such as USB scopes, handhelds, scopemeters, "toyscopes" etc.  I don't know if you are looking for something like that?
Or second hand.

[scroeffie]

thanks all for helping friend says this is the best 300 euros scope that he could find its even better than the 500euros rigol models
for my hobby ,he also says i need probes 1:100 because of the crt psu puls 400....1000v  no idea what he is talking about but i trust him
dont even know how a scope works to much buttons and things on the screen but i wil figure it out
need to fix this psu 

Owon XDS2102A oscilloscoop


https://www.eleshop.nl/owon-xds2102a.html

[Zenith]

It comes with probes, probably 100MHz and switchable between 1X and 10X. Mostly the 10X setting is used. I'd guess your friend recommended 100X probes as well, because you work on tube amplifiers and radios.

A way to become comfortable with it is to play with it with a signal generator or function generator. It doesn't have to be a very good one. If you don't have one, a £10 XR2206 based function generator from ebay would do, or you could put something together with a 555 timer chip, or make a multivibrator.

[BillyO]

If you can arrange a bit more I'd strongly suggest something like the Siglent SDS804X-HD.

It's more than you need right now, but it's amazing how quickly you can grow out of a tool once you realize its effectiveness.

It is also easily "improved" like most of the Siglent scopes.

It will eat the Owon for breakfast as an appetizer.

[Gyro]

If rock bottom price is your absolute priority, the Siglent SDS1202X-E / SDS1104X-E seem to be available at reduced prices, presumably as a result of the SDS800X-HD series introduction.

[5U4GB]

Another item that was very expensive back then was the Logic Analyser. These day, you can get a basic Saleae USB logic analyser clone (which works with open source Sigrok) for <$10 for the 8 bit version. Back when everything was external to the microprocessor, wider LAs were used, typically 24 bits or so. 16 bit Saleae clones or even 32 bit USB models are also pretty cheap now. The work methodology was scope to look at signal integrity/quality, setup and hold timings etc, and the LA for decoding busses and decodes. SPI, I2C etc, weren't a thing back then, so protocol decoding is less useful.

That was one thing I was going to mention, a lot of digital scopes have some decoding and logic analyser functionality built in, and it's extremely convenient to be able to switch from "what does the signal look like" to "what's the information in the signal" without having to disconnect and reconnect a bunch of stuff to go from one device to the other.  If the OP is working with 8-bit micros and older x86 that don't require anything particularly exotic then something with a bit of decoding functionality might be useful.

[Wallace Gasiewicz]

When starting out use 10X probes. The 1X  10X probes are. in my opinion, dangerous to your scope.   
The switches sometimes are not good and just ONE mistake on your part can damage the scope.   So I think the 1x 10 probes should be avoided. Some people even glue them to 10 X position, Also the specs are not as good usually.I do not use 1X probes. at all.   
Many of the cheap Chinese Probes are VERY good and as I said, Very Cheap. Just make sure the probes match the capacitance of your scope input. If you are going to order a pair, ask here for recommendations after you have picked out one or two possibilities.   
I work with HV tube equipment an do not use scope on very high voltages, just measuring the HV is a problem.  I use old HV multimeters with HV leads for HV.   Old military multimeters can have high voltage capabilities. I know these are not as accurate a modern multimeters, but you do not need that accuracy.

If you are going to work on CRTs, may I suggest getting an old TV Picture tube tester. You can modify the base connection to evaluate tubes that are not on the list provided with the picture tube tester. You can even get a good idea if a oscilloscope tube is good or not.   Picture TV Tube testers are very cheap, like $10. I gave one away. If you want one, look for ones that have multiple base connectors with them (for testing different tubes). Most of the CRT testers I have seen are in really good shape and hardly used.

[baldurn]

The Siglent 804XHD might be 409 euro but that little extra brings you from toys to a real tool that will serve you for years. It also has much better resale value.

[jasonRF]

Safety should be the first concern. 

If you are working on Tube radios, the power supplies are likely several hundred volts.  A high-voltage probe from a reputable source may be needed if you are poking around those with a scope. 

[BillyO]

If you are working on Tube radios, the power supplies are likely several hundred volts.  A high-voltage probe from a reputable source may be needed if you are poking around those with a scope. 

A little excessive.  Most standard passive probes are rated to 600V.  That and a little care should be fine for 99.9% of tube radios.  Most 100X probes I've seen are rated over 1KV.

HV probes are usually rated over 10KV and are a bitch to use in tight places.  Might be an idea for the CRTs though.

But whatever gets your goose cooked. 

[scroeffie]

back again have 2 questions .are these any good for me as a beginner   https://www.eleshop.nl/owon-oscilloscope-probes-2kv.html

second question we think we have found the problem of my ibm psu these 2 optos are not working corectly anymore and they are very old like 30+ years old
the monitor also has been working like around the clock in a factory crt monitor is a ibm 8514 there is no schematic that i can find ,other than this small problem \
i already did a full recap some caps where dead .
if any one has a schematic or knows where what kind of replacement i could buy please let me know     

[pcprogrammer]

Since you stated to have no knowledge on using a scope, I would advice to at first get some experience with low voltage signals before diving into devices with high voltages. A big risk lies in using the wrong point to connect your ground lead and then have your scope be at a high voltage on points you can touch. Or blow out things because your scope itself is properly grounded.

Take a look at videos of Adrian Black where he is working on old computers and even monitors using simple oscilloscopes. Might give you some insights in what you need and how things can be done.

[rsjsouza]

Since you stated to have no knowledge on using a scope, I would advice to at first get some experience with low voltage signals before diving into devices with high voltages. A big risk lies in using the wrong point to connect your ground lead and then have your scope be at a high voltage on points you can touch. Or blow out things because your scope itself is properly grounded.

Indeed this is good advice. One suggestion that I can give regarding the choice of oscilloscope that mitigates this issue is a fully portable unit, which is isolated from anything else. I have one of these newer portable oscilloscopes from Zoyi/Zotek (ZT-702S) that allows troubleshooting several minor issues common in computers such as power supply ripple, RTC clocks, activivity on data or control lines, monitor reset lines, etc. Naturally, you might find yourself wanting for a better unit later in time, but these units are a great starter.

if any one has a schematic or knows where what kind of replacement i could buy please let me know     

I suspect you might find some good help with the schematic or tips to troubleshoot your 8514/A in the VCF forums
https://forum.vcfed.org/index.php

[tggzzz]

If you are working on Tube radios, the power supplies are likely several hundred volts.  A high-voltage probe from a reputable source may be needed if you are poking around those with a scope. 

A little excessive.  Most standard passive probes are rated to 600V.  That and a little care should be fine for 99.9% of tube radios.  Most 100X probes I've seen are rated over 1KV.

... and not rated at 600V at "high" frequency.

Always check the V-vs-f derating curve.
Always remember that the highest frequency in a signal does not depend on the signal's period. It depends only on the signal's risetime.

[shapirus]

Indeed this is good advice. One suggestion that I can give regarding the choice of oscilloscope that mitigates this issue is a fully portable unit, which is isolated from anything else. I have one of these newer portable oscilloscopes from Zoyi/Zotek (ZT-702S) that allows troubleshooting several minor issues common in computers such as power supply ripple, RTC clocks, activivity on data or control lines, monitor reset lines, etc. Naturally, you might find yourself wanting for a better unit later in time, but these units are a great starter.

Before all the traditional scope-floating hell breaks loose, it should be mentioned that while these portable (aka floating) scopes are good for preventing the damage of the scope and DUT (as long as all ground leads are connected to the same potential), they do not inherently make measurements safer for the user. That part should be understood, and it was a good advice to accumulate some experience and knowledge before proceeding to probing higher voltage circuits.

[Wallace Gasiewicz]

Before you buy scope probes make sure that the probes  capacitance matches your scopes input. I did not see the values of the 2 KV probes capacitance in the link.

[tggzzz]

Indeed this is good advice. One suggestion that I can give regarding the choice of oscilloscope that mitigates this issue is a fully portable unit, which is isolated from anything else. I have one of these newer portable oscilloscopes from Zoyi/Zotek (ZT-702S) that allows troubleshooting several minor issues common in computers such as power supply ripple, RTC clocks, activivity on data or control lines, monitor reset lines, etc. Naturally, you might find yourself wanting for a better unit later in time, but these units are a great starter.

Before all the traditional scope-floating hell breaks loose, it should be mentioned that while these portable (aka floating) scopes are good for preventing the damage of the scope and DUT (as long as all ground leads are connected to the same potential), they do not inherently make measurements safer for the user. That part should be understood, and it was a good advice to accumulate some experience and knowledge before proceeding to probing higher voltage circuits.

Actually they might make it marginally safer. Avoids deafening/blinding/lung damage/heart attack when something blows up and/or catches fire
Apart from those minor considerations, you are right: an isolated scope woudn't make it safer.

HV differential probe are, for some use-cases, the appropriate choice of probe.

The OP might like to consider that they will probably end up spending money on a scope plus X, and hence to leave budget available for X. (X=probes. PSU, signal generator, meter, protocol analyser etc)

[scroeffie]

i think this scope is the best for me money wise and specs so this one with the probes i posted https://www.eleshop.nl/owon-xds2102a.html

[BillyO]

i think this scope is the best for me money wise and specs so this one with the probes i posted https://www.eleshop.nl/owon-xds2102a.html

That scope is probably not even made by Owon.  It's made by whoever makes Hanmatek scopes and a bunch of other name-less items.  Some 3rd party generic stencil scope maker.

It's up to you however, but I do tend to buy things like this (several hundred $$$) from the people that actually make them and that have a world wide service and support network.

For instance, I would not buy (again) from UNI-T.  They do make their scopes, but service and support are not in their vocabulary. 

[flaotte]

Indeed this is good advice. One suggestion that I can give regarding the choice of oscilloscope that mitigates this issue is a fully portable unit, which is isolated from anything else. I have one of these newer portable oscilloscopes from Zoyi/Zotek (ZT-702S) that allows troubleshooting several minor issues common in computers such as power supply ripple, RTC clocks, activivity on data or control lines, monitor reset lines, etc. Naturally, you might find yourself wanting for a better unit later in time, but these units are a great starter.

Before all the traditional scope-floating hell breaks loose, it should be mentioned that while these portable (aka floating) scopes are good for preventing the damage of the scope and DUT (as long as all ground leads are connected to the same potential), they do not inherently make measurements safer for the user. That part should be understood, and it was a good advice to accumulate some experience and knowledge before proceeding to probing higher voltage circuits.

Actually they might make it marginally safer. Avoids deafening/blinding/lung damage/heart attack when something blows up and/or catches fire
Apart from those minor considerations, you are right: an isolated scope woudn't make it safer.

HV differential probe are, for some use-cases, the appropriate choice of probe.

The OP might like to consider that they will probably end up spending money on a scope plus X, and hence to leave budget available for X. (X=probes. PSU, signal generator, meter, protocol analyser etc)

it is not safe, don't do it. Ok I got it. Like any high voltage device with no cover should not be powered on and lie on the bench.

At the moment I have APC UPS pulled apart on my table. I am really tempted to power scope from power bank and check how actually sine looks like on that unit.
Connect wires, turn UPS on, touch nothing, check the signal, try different load on extension cord, turn it off.
Does not sound too bad, do I miss something?