Looking for an Oscilloscope for Troubleshooting

I'm looking to further my knowledge on electronics repair and was hoping some of you wise old warriors on here could help me choose on an oscilloscope for troubleshooting. I'd be using it for things like CD laser tuning and trouble finding.

Input on things like digital vs analog, bandwidth, etc would be greatly appreciated! :smile-new:
Any recommendations?

 

The general rule with bandwidth is as much as you can get, but if you are working mostly on retro stuff then 100Mhz should be perfectly OK.

For fault finding I would strongly recommend an analog scope - they will give you a usable indication even if the sweep and trigger settings are completely wrong, and this is generally not the case with digital scopes. I have a Tek MSO3034, which is a very nice digital scope, but I still prefer to use an old Iwatsu SS-7810 100MHz analog scope when I am repairing things.

Against this, digital scopes are a lot better at capturing events that don't happen very often, have deeper memories, can store stuff that happens long before the trigger, etc, etc. They also tend to be newer and rather more reliable - but also a lot more expensive.

 

What's your budget for this? You can get cheap PC USB scopes for under 100$ or if your a millionaire you can buy one of those fancy scopes with 1GHz bandwidth and included 32 ports logic analyser that runs Windows OS for around 15K$.

There is no "deal" in this market, at least for new units. The more you pay, the better it is. You've got to look for bandwidth and if you're buying a digital oscilloscope, the number of samples per seconds. Most of them offer the same features so don't spend too much time checking features like triggers, measurements and other gadgets. They will likely be the same for scopes in the same price ranges.

When I was a student in electric engineering, I purchased the Rigol DS1052e on which I used the firmware hack that changes it to a DS1102e, doubling the bandwidth from 50MHz to 100MHz(actually there'sa firmware hack that enables to go up to 150MHz by changing it to a "DS1152e" but the input filters will not permit you to capture a representative waveform). They are decent scopes for 300$, usually come with 2 (cheap but OK) 1X-10X probes and PC software to capture waveforms and control scope via PC by the integrated USB port.

Go check eevblog's forums, there's a good number of users that have this scope.

You can also check your local adds for people giving away(or selling for really cheap) old scopes. They're usually not high bandwidth and might have issues but it's a good start.

 

I have the Rigol DS1052e too

 

I'd say don't skimp on price. You can get second hand scopes cheap, but they're usually either only 20Mhz (fine to learn on, not very practical when you get more into it) or knackered. Get one that's been serviced and you know will last - a warranty is even better. Finding your scope died when you need it most isn't fun... nor is fixing one!

The modern Chinese ones are... well, they're OK, and usually good value for money. Likewise with the software scopes - actually, when they first came out, they offered a great deal for the price. I prefer an old beast, personally. You can pick up a Philips, Tektronix, Goldstar, HP etc. for a reasonable price.

Don't forget you'll need the right test CD for laser diodes... although that isn't always the most complex of discs!

 

I am not knowledgeable when it comes to electronics, though I'm learning slowly.
I'd suggest you check some of the EEVBlog vids on youtube; that guys seems to know what he's talking about.
https://www.youtube.com/results?search_query=eevblog+oscilloscope

 

Dave (EEVBlog) has taught me all i needed to know soldering, what to use, why its best. Dave is the man. When i need to learn something new i goto directly his youtube channel.

 

I'd only go digital. Analog oscilloscopes are more expensive, and often less useful IMO. The most important thing to decide is what's the max frequency you need to handle. That really depends on what you're planning to use it for. Once you figure out what frequency you need, get the oscilloscope with the largest buffer that you can afford. You can often make do with a smaller buffer, but it's much harder to sample your data if you need to observe more information than you can fit in the buffer at the required frequency. You can't do anything about the max frequency though. If you need to be able to observe something at a higher frequency than your oscilloscope can handle, it's basically useless.

For myself, I needed to be able to sample around 150Mhz, and I ended up going with the Hantek DSO-2150 (http://www.hantek.com/english/produce_list.asp?unid=63) because it was the cheapest digital oscilloscope I could find that handled that frequency. I later upgraded to the DSO-5200A when I had a bit more money, because it gave me a much larger buffer. You can find both of these on ebay easily. Very few cheap oscilloscopes seem to be able to reach these kind of frequencies. If you only need something up to around 50Mhz, you've got a lot more options.

Edit: I should add, Hantek have come out with a new generation of oscilloscopes since I bought my ones. You might want to check out the latest models and compare the features/price if you're considering a Hantek unit.

 

That item you linked to only shows its a 150MS/s, 60MHz bandwidth so how does it go to 150Mhz?

 

Quite right, sorry about that. I'm obviously forgetting what I did when. The 5200A has a 200Mhz sample rate, which I've needed for a few tasks. I bought the 2150 first, then later upgraded to the 5200A for the larger buffer. I must have done all the higher frequency sampling after I got the 5200A. I forgot the 2150 had a lower sampling rate.

 

Thanks for the feedback everyone! (Ha! Pun) I'll have a good read through and will pick out a winner in the next few weeks or so!
Until then, any more suggestions are welcome of course!

Oh yes EEVBlog, I've definitely stumbled onto that a few times in the past! Bookmarked him!

 

For repair you can get away with anything.

Personally I like HP/Agilent scopes.

Remember sample rate != bandwidth != system bandwidth, which must include all frequency components/harmonics