scope suggestions for prototyping and repair. - Page 1
Forum section: electronics / testgear

author: bill_c
author_rank: Regular Contributor
timestamp: April 12, 2020, 07:01:27 pm
content: I work on a little of everything so looking for a good scope (new or used) for prototyping and repair, but not like $5,000+ good. I prefer a stand alone unit, but if price vs performance says otherwise, I would accept one of those USB connected things as long as it works with Linux and has a low chance of frying my computer when I connect the probes to the wrong thing. Please no $99.95 hand held DSOs.I really need serial decoding (need 9 bit or more, many only do 7 and 8 bit), 232,422,485, SPI, and I2C.I use 300+Mhz MCUs so need something fast enough to watch rising and falling slopes on I/O between chips and boards, MOSFETs, and things like encoders. I don't need to measure down to the .01%, just want to see if an encoder at 100Khz and 30 feet of cable looks more like a square wave or a sine wave. (same with higher speed MCU I/O less cable)I also need to be able to measure noise of switching/linear power supplys, ADC inputs, DAC outputs. Again, just want to see if switcher/etc. filtering is ok or if I need to change something.I would be nice to have 8+ I/O logic analyzer option, but its not a deal breaker. Open to suggestions for probes also.OH, it also need to be good enough for repairing audio amps and such

author: Fungus
author_rank: Super Contributor
timestamp: April 12, 2020, 07:07:20 pm
content: The Rigol MSO5000 series is for you...Under $1000 and you can easily hack it up to 350MHz and it has sample rate to spare for rising edges, etc.

author: bill_c
author_rank: Regular Contributor
timestamp: April 14, 2020, 04:30:51 am
content: That Rigol MSO5074 does look nice with the upgrades. The logic probes seem overpriced for my needs but I found Gandalf_Sr is making PCBs for a DIY version of those.I am a bit hesitant on spending $1000 on a suggestion from a single internet stranger, can I get a second opinion from someone else? Cause I would totally trust 2 internet strangers.

author: james_s
author_rank: Super Contributor
timestamp: April 14, 2020, 04:45:37 am
content: There are lots of reviews. Search the forum for MSO5074 and see what others have said about it.Look around at the comparable offerings from Siglent, Keysight and others, you should be able to narrow it down to 3 or 4 reasonable options within your budget.

author: DaJMasta
author_rank: Super Contributor
timestamp: April 14, 2020, 06:10:31 am
content: Good advice above, Siglent's 5000X series will probably do what you're looking for, and Rhode & Schwarz's RTB2004 in a higher bandwidth variant would be a good choice. A Keysight 3000 series MSO is a fine scope, but the chip it's based on is older and has some limitations for certain applications (high resolution displays, FFT, memory depth), though it's also got some nice features which are still competitive with newer scopes. LeCroy and Tek have options for this sort of thing, but I think both's current generation offerings are considerably more expensive than those above.

author: Fungus
author_rank: Super Contributor
timestamp: April 14, 2020, 11:23:20 am
content: Quote from: bill_c on April 14, 2020, 04:30:51 amYou just saved a couple of grand by buying the Rigol... plus you got a free signal generator.

author: bill_c
author_rank: Regular Contributor
timestamp: April 14, 2020, 01:41:42 pm
content: Thanks everyone, I took a look at those listed above and more. Fungus is right, the Rigol DSO is the one for me after all.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: April 14, 2020, 07:30:01 pm
content: Quote from: bill_c on April 14, 2020, 01:41:42 pmI don't have any experience with the Rigol MSO5074 so keep this in mind, but just a word of warning since you mentioned "300MHz+ MCUs", because a 350MHz scope is unlikely to be an adequate tool for this. To adequately measure the rise time of a 300MHz clock signal you'd be looking at 2+GHz scope. Even with moderate requirements you really want something with at least 1GHz BW.Unfortunately, new scopes at these BWs vastly exceed $5k (even the ones from Rigol and Siglent), therefore you might want to consider buying 2nd hand. Considering your other requirements (like serial decoding), there are several options like the WaveRunner 6kA/WavePro 7kA/WaveRunner Xi Series from LeCroy, or the Agilent XP-based Infiniium 54800 and DSO/MSO 8000 Series.A 2GHz WavePro 7200 can often be had for somewhere around 1.5x the price of the Rigol, and should do anything you need. They support a vast range of options, from serial decode for a long list of standards to advanced toolsets like power analysis (all hackable). The only thing they are lacking is the LA part, for which one of the better USB devices would be an option.The Agilent Infiniium 8000 exists in 600MHz and 1GHz variants (the 600Mhz variant can be modded into the 1GHz variant by removing a SMD resistor), both also as MSO. They also offer serial decode, although much more limited than the LeCroy scopes (but the option should still cover your requirements). The same is true for the XP variants of the older 54800 Series, which also offers higher BWs.Just saying...Quote from: Fungus on April 12, 2020, 07:07:20 pmThe excessive sample rate of 8GSa/s for a BW of only 350MHz is pretty meaningless as the scope will not show any details beyond its analog BW anyways, no matter what the sample rate is. All it does is filling up the sample memory faster.-- There was a MSO option for WaveRunner 6k and WavePro 7k called MS-32 which was crap, and the MSO pods for the WaveRunner Xi are rare and very expensive.

author: nctnico
author_rank: Super Contributor
timestamp: April 14, 2020, 08:08:21 pm
content: Quote from: bill_c on April 14, 2020, 01:41:42 pmWell... several people sold it already. It may look nice on paper but do check the 'known bugs' list somewhere on this forum.If you are looking for an oscilloscope with mature firmware then look at GW Instek, Keysight, R&S or Siglent. Usually looking at high frequency signals doesn't require much in analysis abilities. Used (older) >=1GHz oscilloscopes are not extremely expensive. All in all you might be served well by a new 100 to 200MHz oscilloscope combined with a used >=1GHz oscilloscope.

author: jemangedeslolos
author_rank: Frequent Contributor
timestamp: April 14, 2020, 08:08:31 pm
content: Hello,I think what fungus meant was this MSO5074 can sample at 8Gsa/s....so 4 x 2Gsa/s.And severals users here have measured more than 450Mhz BW on this scope so 4x2Gsa/s no longer seems overkill if you need high BW on all channels.

author: jemangedeslolos
author_rank: Frequent Contributor
timestamp: April 14, 2020, 08:10:49 pm
content: Quote from: nctnico on April 14, 2020, 08:08:21 pmYour ctrl c / ctrl v keys must be very used, right?

author: nctnico
author_rank: Super Contributor
timestamp: April 14, 2020, 08:12:31 pm
content: Quote from: jemangedeslolos on April 14, 2020, 08:10:49 pmSame question, same answer. Everyone does that.

author: Fungus
author_rank: Super Contributor
timestamp: April 14, 2020, 08:16:04 pm
content: Quote from: jemangedeslolos on April 14, 2020, 08:08:31 pmYep. And they can still show some signal up to about 1GHzhttps://www.eevblog.com/forum/blog/new-rigol-scope/msg2446644/#msg24466448GSa/sec isn't overkill when all 4 channels are on.

author: Andreas
author_rank: Super Contributor
timestamp: April 14, 2020, 08:16:54 pm
content: Quote from: Wuerstchenhund on April 14, 2020, 07:30:01 pm... and a active oscilloscope probe with less than 1 pF capacity which does not change much the wave form (costing a arm and a leg).with best regardsAndreas

author: Fungus
author_rank: Super Contributor
timestamp: April 14, 2020, 08:18:07 pm
content: Quote from: Andreas on April 14, 2020, 08:16:54 pmBottom line: The next step up from the Rigol will be abigstep up in price, too.

author: james_s
author_rank: Super Contributor
timestamp: April 14, 2020, 08:26:34 pm
content: Quote from: Wuerstchenhund on April 14, 2020, 07:30:01 pmBUT you often don't need to accurately measure the rise time of a 300MHz clock signal. Most such MCUs will have an internal multiplier generating the core clock from a much lower frequency source, and even if you do need to look at a 300MHz signal you can do that, you just need to understand the limitations of the tools you have and how to interpret what they are telling you. *ALL* scopes lie to some degree, and no matter how much bandwidth you have, sooner or later you will encounter something beyond the ability of the instrument you have on hand to really properly display. This is fine, in the real world nothing is ever ideal, as long as you are aware of the limitations you can in most cases work around them. While I have a 1GHz scope, it's rare that I actually need anywhere close to that bandwidth and I'm typically limited by the probes I have anyway. In practice this is not really an issue though, the fact that the corner of a square wave appears a little rounder that it actually is doesn't matter, I can still see that it's a square wave, that the frequency and amplitude are about right, that a digital bitstream is ones and zeros with the levels and edges within tolerances.Lacking infinite budget, you work around limitations and get by with what you can reasonably afford.

author: jemangedeslolos
author_rank: Frequent Contributor
timestamp: April 14, 2020, 08:35:29 pm
content: Quote from: nctnico on April 14, 2020, 08:12:31 pmYes and no.As I said before, I have a lot of respect for your experience and your knowledge.But you keep saying wrong things about Rigol (what you said also not so long ago about Siglent).This MSO5074 is not full of bugs. Maybe 50% of reported bugs are minors.... or more a problem between chair and scope.If i look quickly the R&S topic, I see lots of bugs inside the RTB2000 series.... But it is certainly not the case if I had to look deeper (I hope).

author: nctnico
author_rank: Super Contributor
timestamp: April 14, 2020, 09:23:26 pm
content: Just look at the reasons why people sold their Rigol MSO5074. I'm pretty sure that when you dig deeper (really kick it around instead of doing some cursory testing) you'll find a lot more problems.

author: stafil
author_rank: Regular Contributor
timestamp: April 15, 2020, 12:46:05 am
content: I am not going to recommend a specific scope, but to advise you to go for an easily hackable one. You lose a lot of value otherwise.

author: Fungus
author_rank: Super Contributor
timestamp: April 15, 2020, 06:42:28 am
content: Quote from: nctnico on April 14, 2020, 09:23:26 pmWhy don't you post a few links instead of just insinuating. I'mverysure that most people haven't sold theirs.

author: jemangedeslolos
author_rank: Frequent Contributor
timestamp: April 15, 2020, 07:22:04 am
content: Quote from: nctnico on April 14, 2020, 09:23:26 pmOh sorry, I didn't know you bought one and found so much bugs. This explains why you are so sure of yourself.I don't know everyone on the forum. IIRC, 3 people sold their MSO5074 explicitly.I haven't read everything and maybe some people sold it without making noise.Of the three I know about, two of them sold their MSO5074 because it is still very popular and under warranty and so, sells very well.So there was not a lot of money to add to try the new Siglent SDS2000X+ which has just been released.Bigger and better screen, Lecroy UI and much much more frequent/quick firmware update.....and bode plot.A function that Rigol has been promising for months.The other, (TK I think?) sold his for a Keysight 1000X.At first, he found the keysight much better at serial decoding.....But when he correctly configured his Rigol, he found the same performance in terms of triggering on rare events ( at least on high speed SPI decoding ).He said very bad things, like you on the Rigol. But as soon as someone asks for details or a specific example, no one answers.It may be time to come back to the good side of the force.

author: bill_c
author_rank: Regular Contributor
timestamp: April 15, 2020, 08:03:55 am
content: Thanks everyone for all the info. You each have valid points and everyone looks at the problem from different directions and that is a good thing. I have read many of the related posts on this form and it has been very helpful. The problem (for me) is there are way too many features, specs, options, and bugs for each scope to really compare them all (like how do you put a value on each attribute?). And there are too many scopes to pick from, more so when including used market. I do understand this one will not do everything I need every time, partly cause I never know what I will be doing tomorrow, but it will do most of what I need for now. I may very well buy another used ~2GHz scope, but that will be later. I would like to have a better scope, but when you have to add in all the options, they usually end up $5k or more, which is a price I can't justify right now.

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: April 15, 2020, 09:00:27 am
content: Bill,Thanks for the mentionI own a Keysight MSOX4054A with all options (legit); it's worth about $10,000. It does 5Gsps and has hardware serial decode. It's for sale on eBay right now with nearly 100 views and 5 watchers.I recently bought a Rigol MSO5074 with all options (free from Rigol); it cost me $1,000. It does 8Gsps and has hardware serial decode. I made the LA cable set and can help set you up with either bare PCBs ormaybeeven made up PCBs (I have a few) but that would be as a favor as my time is worth more than most people want to pay.I see the Rigol as being able to do 99.9999999999999999999999% of what I want to do on the Keysight; to prove that I bought the Rigol and tested it, it never crashed, the LA and decodes worked, it's clearly a keeper. Once I got to that point I took the Keysight off my bench and looked at it for a week, then I listed it on eBay. I didn't do it because I was desperate for money, I'm not. But the Coronavirus lockdown was the trigger to reevaluate and make changes in my bench, so that have saved me a lot of money.For some reason, nctnico seems always to rip on Rigol and push GW Instek; his claims that the MSO5000 is full of bugs seems out of kilter with my experience with the scope, it works, well. His claims that GW Instek is superb gear have been challenged by many.PM me if you decide to buy and want some LA probes that cost less than an eye and a kidney.

author: nctnico
author_rank: Super Contributor
timestamp: April 15, 2020, 09:30:42 am
content: Quote from: jemangedeslolos on April 15, 2020, 07:22:04 amJust look into the history of Rigol. At least Siglent has learned from their mistakes in the past. They setup a pool of beta-testers and they don't even seem to care to compete with Rigol on price. If someone pays me to test the Rigol MSO5000 I'd be happy to take it through my standarised oscilloscope torture test.QuoteAnd right there is your answer. I rest my case.

author: jemangedeslolos
author_rank: Frequent Contributor
timestamp: April 15, 2020, 10:12:25 am
content: Quote from: nctnico on April 15, 2020, 09:30:42 amBode plot is a function that is not mentioned anywhere in their datasheet.This is an addition that will be made at the request of customers so we can't fault them.The annoying thing is constantly pushing back the release date, but I'm not one of those people who watch every day for a new firmware versionThe oscilloscope already works well like that, if it releases the bode plot one day I would be happy.From what I understand, they will release this year a new oscilloscope based again on their own Asic.So we can hope that the improvements made on this firmware will be replicated on the previous models.The SDS2000X+ seems a very nice instrument for the price.....but there are maybe between 10 or 15 owners on the forum.Statistically, there are necessarily fewer bugs reported.And Siglent also has drawbacks that Rigol does not have so you have to make a choice ( and pay 30% more if you just want a DSO....60% if you want to buy the Siglent LA probe thanks to Gandalf_Sr and his low cost Rigol probes ).

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: April 15, 2020, 10:39:50 am
content: Quote from: jemangedeslolos on April 15, 2020, 10:12:25 amI'mFAMOUS!!

author: jemangedeslolos
author_rank: Frequent Contributor
timestamp: April 15, 2020, 10:44:32 am
content: You deserve to sell at least 2 kit per MSO5000 sold, so you would get rich and you could finally buy a real high end, bugs free scope ( you know, those recommended by ntnico ). And the planet could finally continue to turn.

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: April 15, 2020, 11:17:43 am
content: Quote from: jemangedeslolos on April 15, 2020, 10:44:32 amThanks, I don't think I'd get rich though. I might have enough to afford some lolos though (whatever they are).

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: April 15, 2020, 12:08:08 pm
content: Quote from: jemangedeslolos on April 15, 2020, 10:12:25 amYou're missing that some of these owners are dedicated beta testers for Siglent, i.e. they are not just average users who may or may not stumble on a bug and then may or may not bother reporting it. These testers are actively putting the scope through its limits to find and report any bug, problem, issue or even area where things can be improved, and while this doesn't guarantee every bug will be found (and not every bug might be addressed immediately by Siglent), it has resulted in a huge improvement in the maturity of firmware when products are released.And Siglent has generally been pretty fast in addressing remaining issues, unlike Rigol which often tends to take its time.The other thing is that Siglent's co-operation with LeCroy has resulted in many of the advanced features found in LeCroy scopes becoming available in Siglent scopes. I only know the SDS5000X but from what I heard many of the same features went into the SDS2000X+, and most of them are not available in any Rigol scope including the expensive MSO8000.Having said that, if the OP can live with the limited BW then the Rigol MSO5074 should work fine. From what I read a lot of bugs have been fixed, and even the hardware issue with the dim screen has been addressed.I'd still consider the SDS2000X+, though.

author: jemangedeslolos
author_rank: Frequent Contributor
timestamp: April 15, 2020, 12:31:46 pm
content: Quote from: Wuerstchenhund on April 15, 2020, 12:08:08 pmYou're right and it's really something that Rigol is missing.Not to mention dedicated beta testers, why not have a Rigol representative on this forum regularly ? communication would be more fluid.That said, Siglent release a new firmware that correct severals bugs only few weeks after avaibility so as you said, it is not perfect either.I hope Siglent will increase its market share, maybe that will force Rigol to improve in this regard.

author: james_s
author_rank: Super Contributor
timestamp: April 16, 2020, 06:43:46 am
content: Quote from: bill_c on April 15, 2020, 08:03:55 amThis doesn't have to be a major life decision. It will in all likelihood not be the last scope you ever own. You may well find that it's handy to have more than one scope, or if you find that the one you bought is just not the right scope for you, if you've taken good care of it you may get most of your money back by selling it. Just a few weeks ago I happened to see a lightly used 1054z sell on ebay for slightly more than they are brand new from Tequipment, the entry level stuff is so cheap to begin with that it doesn't tend to drop in value much. Chances are once you've used a scope for a bit you'll have a better idea of what you really need. If I were you I'd buy something modest and use it for a while then go from there.