Recommendation on selecting a used oscilloscope? - Page 1
Forum section: electronics / testgear

author: nathankwan
author_rank: Contributor
timestamp: May 14, 2024, 03:10:43 am
content: Hi guys, I must admit I am kind of obsessed with good scopes... So please try to focus less on the actual need (I'm working below 100MHz so a TDS220 should be enough in that case, but I just want as much performance as possible as long as the price is acceptable)I would like to have an affordable used scope, with relatively good performance and endurance. I've done some digging and got this list:> TDS3000B series, or more precisely TDS3014B, with easy upgrade through ethernet.> Lecroy wavesurfer 44Xs (or similar), would also like to upgrade sample rate but just don't know how (I've seen someone succeeded).> TDS784D/794D, just like its color CRT...But I also have concerns about each one above:> TDS3000 series have shallow memory depth and crazy-low waveform refresh rate, but their price are around $500 in where I am.> I love Lecroy's enclosure size and Windows OS, wfm refresh rate is high, but expensive (around $1500, old 7300A are cheaper, but so heavy).> CRT attracts me, memory depth and wfm refresh are fair, but too heavy, and only 1GS/s when all channels on, etc...I came here to see if anyone can share some other models that I'm not farmiliar with, like Agilent/Keysight, R&D, Siglent(I don't really like), RIGOL(I don't like either), YOKOGAWA etc...

author: tautech
author_rank: Super Contributor
timestamp: May 14, 2024, 04:50:53 am
content: Quote from: nathankwan on May 14, 2024, 03:10:43 amYou and me both.QuotePlease tell why ?My first DSO was a Tek TDS2102B (now busted) and later had my hands on TDS210 and TDS10**B I don't remember which model, 60 MHz IIRC but they were both busted and then repaired and sold.The earliest Siglents we had 11 yrs ago were easily as good DSO's as the Tek's and in my experience have proven to be more reliable.You should take a long hard look at SDS804X HD ......

author: Fungus
author_rank: Super Contributor
timestamp: May 14, 2024, 06:24:02 am
content: Quote from: nathankwan on May 14, 2024, 03:10:43 amThe new 12-bit Rigols/Siglents arefarbetter than anything you'll find second hand for the same price.

author: pdenisowski
author_rank: Super Contributor
timestamp: May 14, 2024, 09:59:53 am
content: Quote from: Fungus on May 14, 2024, 06:24:02 amHaving owned a bunch of different "hobbyist" oscilloscopes over the years: I agree completely that you will probably get a lot more bang for your buck just buying a new hobbyist scope versus buying a used scope. Even scopes I bought new 10 years ago look pretty ... sad ... compared to what I could buy today for the same money.Huge difference between buying a 20 year old multimeter and a 20 year old oscilloscope

author: watchmaker
author_rank: Unknown
timestamp: May 14, 2024, 10:27:17 am
content: ^

author: nctnico
author_rank: Super Contributor
timestamp: May 14, 2024, 06:20:15 pm
content: Quote from: nathankwan on May 14, 2024, 03:10:43 amAs others noted, for $500 you can buy a new DSO. Even a super low-cost Fnirsi is likely a better buy as a daily driver for measuring sub 100MHz signals.The second hand scopes you listed are only interesting if you need >500MHz bandwidth OR advanced analysis. A Lecroy 7300A is a great scope for signal analysis (I have one myself) but not very suitable as a daily driver.A lot depends on what you need though. If you are only working on analogue circuits, any DSO will do.

author: nathankwan
author_rank: Contributor
timestamp: May 15, 2024, 01:58:18 am
content: Quote from: tautech on May 14, 2024, 04:50:53 amI haven't used any of Siglent scopes but I recall people around in the lab during my graduate time were mentioning about the reliability and accuracy issues (and strange bugs, slow response time in UI, etc.)... But that's more than 10 years ago, I believe these days Siglent scopes must have developed, but those words do have a long impact...I'll take a look at SDS804X HD

author: BillyO
author_rank: Super Contributor
timestamp: May 15, 2024, 02:10:24 am
content: Quote from: nathankwan on May 14, 2024, 03:10:43 amStrictly analog signals without risetimes of 3.5ns or less?I build little computers and use microcontrollers that operate at under 20MHz, however they make signals with frequency components near the GHz range. You'd be amazed at what more you can see on these tings with a 600MHz scope over what you see with a 100MHz scope. All sorts of things that can and do cause trouble.

author: David Hess
author_rank: Super Contributor
timestamp: May 15, 2024, 12:42:22 pm
content: Quote from: nathankwan on May 14, 2024, 03:10:43 amI am not sure where the "crazy-low waveform refresh rate" comes from. The specifications list 400 waveforms per second in normal mode and 3,600 in fast trigger mode. Tektronix considers this series to be digital phosphor oscilloscopes. Performance down to 15 or 30 waveforms per second is still real time, albeit not so good for capturing rare glitches. These are also "real time" oscilloscopes as Tektronix uses the term so memory and sample rate are not shared between channels.Memory depth is 10,000 point maximum, but these oscilloscopes have a real delayed sweep and trigger so this is not as much of a limitation as it would be in a more modern instrument without them.I agree with nctnico that for that price, you are likely better of buying a less expensive Siglent DSO.

author: moerm
author_rank: Regular Contributor
timestamp: May 16, 2024, 02:12:02 am
content: Quote from: nathankwan on May 14, 2024, 03:10:43 amDefine 'good', not to quarrel with you but to better understand what your priorities and desires are.Quote from: nathankwan on May 14, 2024, 03:10:43 am"Windows OS" inmyview is not a plus but rather a major minus, especially for an everyday go-to scope.As you seem to want a reasonably high WUR scope with attractive features and at a low-ish price I'd go for a Siglent without even a second thought. You said you don't like Siglent but I think you should consider the fact that back then they were relatively new. Nowadays however they have lots of experience and are a good choice and btw. also a choice that is likely to last and serve you well for many years.Re 'LeCroy': I also was attracted but recently I learned that, at least as a private or small customer you are unlikely to get support but rather a cactus in your rear from them.Also note that to some degree Siglent can be seen as LeCroy-ish that is they produce some hardware for them and also seem to have a similar approach.But again: Tell us what you mean when saying 'good' .(edit: corrected stupid quoting mistake)

author: points2
author_rank: Regular Contributor
timestamp: May 16, 2024, 02:21:11 am
content: Hi,"used scope" ?here is my "tiny" experience :1. like the other mates above that said : a "new" scope is far better than any oldies.I agree completly... given that any oldies have a no/tricky connections to PC, not like with any "new" => useless in 2024 ! :-)WTF buying an old blulky box that can measure any stuff within : 500MHz max & 2GS/s...That range of scope = any "smartphone" => the last on the market is far away the perf. of any oldies2. OLD = COOL & CHEAP... if... your need is peculiar.given any scope, the price is related to GS/s & BW (my 2 cents...).Lucky me, I managed to buy a sampling scope at dumped price (old-stock) ; it's an old scope, but it can do measurement that NO-NEW-DSO can do => in that case => "old" = OK given market prices of these peculiar scope.

author: nathankwan
author_rank: Contributor
timestamp: May 17, 2024, 06:28:45 am
content: Quote from: David Hess on May 15, 2024, 12:42:22 pmI think fast or slow is relative, and it's my bad not pointing out my level of reference.I got a TDS644A($400 w. SPC failing but little DC offset) and a TDS784C($450 fully functional) years ago as my first attempts to develop my own electrionic lab. 784C have refresh rate up to 400K wfm/s, 644A should be 100 wfm/s(possibly limited by the slow ADC since those samples are stored in analog CCDs to achieve cheap 2GS/s). These bulky scopes formed my upper and lower bounds on refresh rates.However these TDS600/700 are released at the 90s, so I think a rather high-end scope released in 2008 should have reasonably high refresh rate (just to be clear this is only describing my feeling about hardware developments over the years), so knowing it's only around 3000wfm/s gives me the impression of "crazy-low".Again, I love scopes, I am greedy and want more performance, that's it.I like to put scopes into different categorys using their sample rates:CAT I-> ~1GS/s scopes - like TDS220, cheap, handy and everywhere, If I want one of these, I'll buy a new one as they are definitely far better than any used old-timers.CAT II-> 2.5GS/s~5GS/s - like TDS3000/MSO3000, mainstream, around the edge of my financial power, If I want one of these, I'll be choosing among a) a new CAT II scope, like MDO34-200/MDO3024, or b) a used CAT III scope, like Lecroy WS104Mxi-A or DPO/MSO4104B.CAT III-> 10GS/s above - like DPO7000C, high-end, If I want one of these, I'll have to buy a used one.THIS IS WHY I CAME HERE.CAT IV-> over 40GS/s, far from cheap, totally impractical to purchase for personal use.(also I found old tek 7854/7904 VERY attractive........)

author: coromonadalix
author_rank: Super Contributor
timestamp: May 17, 2024, 10:30:34 am
content: @nathan as a good resume,as an hobbyist at homei tried some old fluke 100Mhz portable scope .... works but ...tried the new cheap Hantek 2d15 model. was ok but basic ...i work with old turd like TEK 7404 and 7254b, yeah yeah Windowish platforms, if they are well maintained they work, until an hard drive crash or the famous dallas clock dies, if you did not saved the power pc settings it may take a while to restart themwork with 2s Siglent sds 1000x, hacked to 200mhz simple and fun to usework with a Rigol, hacked too to 200mhz works fine but like the Siglent a little more, but with scripting / python .. Siglent is way betterwork too with a Picoscope 3406d, practical to say the least, but man very very expensive 3400$ CAD outchwanted a used Lecroy 1 - 2 ghz models, but as mentioned, you're almost out of luck if it break, some good threads here ... unless you find a clean one and self test passed at a good price ??oldies like tds 5k or 6k mmmm you have to see all the spc tests etc ... before even buying one, same for 7 k series, but 7k series are biiiiiiig heavyyyyyy bulkyyyyyywe have evaluated the new Siglent SDS 7k series, my boss is hesitating ... but man this scope was NIX based and runned darn well for the tests we needed / done. having 27k$$ CAD i would have bought it right away lollAgilent mmmmmm not, now they don't deal with single individual ... not new for sure, maybe some Infinium seriesin the end good ol scope depends of your need, but if you compare modern things with the oldies ... you'll be deceived in some ways, you have to know your needs for sure, and know how to deal with them if they break ??my 2 centsstill some good ol series of tek tds 7xx series up to 1 gig, you can do some BW upgrades ...tds3k serie, way overpriced for what they offer, but BW upgradeable tooand now the race between Rigol and Siglent give us more for the money ... with easy BW upgrades cough cough loll same for many items, sig gens etc ...

author: nathankwan
author_rank: Contributor
timestamp: May 21, 2024, 06:09:26 am
content: Thanks for the posts guys, I think putting my tek complex aside, it's the time of Siglent.

author: figgie
author_rank: Contributor
timestamp: May 21, 2024, 07:45:42 pm
content: Quote from: moerm on May 16, 2024, 02:12:02 amSo I think there is some region issue on support for Lecroy.I am a TINY customer. Like hobby MAYBE going to small business size along with used equipment budget BUT i am located in USA.I have had interactions with Lecroy directly and they have been super responsive to me on some key issues, some software notes and calibration procedures. IN all cased they were responsive. 1 time it did take them a bit as they were researching on their back end on some items i reported.Mind you i am using a Lecroy Waverunner HRO 66zi circa 2012 (bought used from ebay for $1k flat since it was "erroring" out, long story short, there was numerous bad sectors on the OEM 160GB Western Digital Black drive that I fixed and then clonded over to 1TB corsair SSD). Currently it is running MAUI 10.7 without any issues.You mileage will vary based on region and if you are a business or not.

author: stj
author_rank: Super Contributor
timestamp: May 22, 2024, 03:47:20 pm
content: dont buy "old" used scopes if you just want to use them.i am in the prcess of replacing around 80 capacitors in a scope made in 199626 of them are SMD and ALL have leaked!

author: David Hess
author_rank: Super Contributor
timestamp: May 22, 2024, 07:10:41 pm
content: Quote from: stj on May 22, 2024, 03:47:20 pmYou should have bought an older scope.

author: points2
author_rank: Regular Contributor
timestamp: May 22, 2024, 10:25:02 pm
content: Quote from: coromonadalix on May 17, 2024, 10:30:34 amwell...I may be wrong but, as I said above :why bother in testing / having any scopes that perform within the same range of "sample rate" & BWSimple fact : "same range of "sample rate" & BW" => we end up to a question of "taste" vs the interface, simply because the results are equal.

author: @rt
author_rank: Super Contributor
timestamp: June 18, 2024, 02:16:22 am
content: I've had used scopes all my life going back to BWD (Australia).I got a Tek 210 yesterday, for one job, intended for resale, which is exactly why I selected this brand,and can't believe Tektronix actually has fans. Fans FFS!What a dog of a thing.The knobs fall off, the power button was broken and just sitting in position.The handle broke off when I got home just from being brittle, and it landed on a tile floor.It still works, so good job there! Half of the units in the lot I picked from had burned or delaminated screens,BNC socket of channel A was loose. Opening the unit broke every brittle lug on the bottom of the unit of course.Then I noticed the fix for the safety recall bends the input PCB. That might also be the DAC and a bunch more stuff.I was in love with it's appearance, and light weight, and tidiness. I was a Tek head for a couple of hours.

author: EEVblog
author_rank: Unknown
timestamp: June 18, 2024, 02:22:45 am
content: Quote from: Fungus on May 14, 2024, 06:24:02 amI have to 2nd this.Also take up way less bench space than sold oldie, as much as like them.

author: tautech
author_rank: Super Contributor
timestamp: June 18, 2024, 04:28:09 am
content: Quote from: @rt on June 18, 2024, 02:16:22 amVery common as these never used a bulkhead to properly secure the weak 2 post BNC which is a known weak point in these but can be remedied with some ingenuity.QuoteYou'll get over it.

author: @rt
author_rank: Super Contributor
timestamp: June 18, 2024, 04:54:19 am
content: Quote from: tautech on June 18, 2024, 04:28:09 amOver it alright. They never soldered the tops of the connectors where they do have tinned solder pads,and the plastic case doesn't allow for much solder to be there.I'm not currently in industry... only comparing it against cheaper scopes I've found on the used market as a hobbyist.It was advertised with a missing knob, and when I went and saw multiple units, I offered $50 extra for him to take the knobfrom another with missing knobs and include it to complete mine. I thought I got a knob that got damaged, but now it'sobvious it fell apart and has been glued together. After a day, that's the only knob that hasn't fallen apart!As a disability pensioner, it's hard hitting since the purpose of it is an act of altruism, and then it goes again.

author: tautech
author_rank: Super Contributor
timestamp: June 18, 2024, 07:22:35 am
content: Quote from: @rt on June 18, 2024, 02:16:22 amWhich models ?Had and repaired a BWD 635 IIRC.Quite nice CRO it was too, ficked like so many others.....

author: smaultre
author_rank: Regular Contributor
timestamp: June 18, 2024, 08:04:48 am
content: For everyday use TDS3000B (Upgraded to 3064B) is the better choice.Lightweight, silent (you need to change FAN), wide bandwidth, 9bit (good precision) Tonnes of CHEAP active probes - high frequency, high volt, balanced, HV+balanced. When you burn you probe, its not such a trouble (when you burn your TDP1000 or so)..Also i like the Fluke 199C for mobility and HV+balanced inputs.But if i need serious analyses, deep memory, decode, & high frequencies, i use Windows based 30 Pound monster))

author: @rt
author_rank: Super Contributor
timestamp: June 18, 2024, 12:34:28 pm
content: Quote from: tautech on June 18, 2024, 07:22:35 am539C. Not my first, but oldest. It's intensity was still right up there.I had an ok DSO with a dud channel also, and got rid of both when I thought I'd have to move.That might be part of the appeal of the light weight part of this one.Thinking further, the only way I could be influenced to buy this Tek was by seeing similar in Jeri Ellsworth videos.

author: BillyO
author_rank: Super Contributor
timestamp: June 18, 2024, 03:47:59 pm
content: With an old Tek TAS475 selling in working condition for over $500US these days, not buying something new for that price is just silly. Unless you are getting something in verified working condition for next to nothing, go with something like a Siglent SDS800X HD or a SDS1000X E and get a quality, competent instrument that runs circles around the old girl and come with a warranty.Of course, maybe you want the challenge of restoring an old beauty and maintaining it and are not really interested in just getting on with a good scope.

author: TomKatt
author_rank: Frequent Contributor
timestamp: June 18, 2024, 04:15:27 pm
content: I love CRO gear and still use my HP 180A regularly for analog work. It was my only scope for many years and did virtually everything I needed. And despite being nearly as old as I am, it powers up every time and operates flawlessly with a nice, crisp trace.But since getting my Siglent SDS1104X-E and now the SDS800X HD, there is no way I'd buy an old, used CRO unless I was specifically looking for collectible vintage test gear. For everyday use, modern gear is more reliable and provides a magnitude greater feature set.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: June 18, 2024, 04:49:28 pm
content: I am with TomKatt and BillyO on thisSeems to me that the new scopes have so many functions they are in danger of no longer even being called "Scopes"I bought an Infinium Agilent Scope used a few years ago and it seems to me that for the price I paid then, you can get a NEW Sigilent with more Functions.Please note that I do not have a new Scope and am stuck in Infinium Land. Maybe not for long though.About antique CRT scopes: I really like them. There are a few things I am aware of that the old Analog CRT scopes do better, but you probably do not need a CRT scope and if you happen to find a use for one, probably a 20 MHz Analog can be found for $20 if and when you think you need it.

author: Fungus
author_rank: Super Contributor
timestamp: June 18, 2024, 05:08:38 pm
content: Quote from: TomKatt on June 18, 2024, 04:15:27 pmThat "crisp trace" is because it's hiding things from you, it's like only ever working in "hires" mode on a modern 'scope'.Compared to their predecessors the traces on the new 12-bit DSOs are plenty "crisp" though.Quote from: TomKatt on June 18, 2024, 04:15:27 pmTwoorders.

author: David Hess
author_rank: Super Contributor
timestamp: June 18, 2024, 07:29:25 pm
content: Quote from: TomKatt on June 18, 2024, 04:15:27 pmThey are an order of magnitude more convenient, but I am not sure about having an order of magnitude greater feature set. They have all kinds of automated measurements, which save time, but it is an oscilloscope, so I am more interested in what the shape of the wave is.They are more reliable only because they are new and old oscilloscopes are old, but I doubt current DSOs will operate for as long. How many modern DSOs have failed because of failed storage or loss of calibration data? If something breaks, throw it away, and buy a new one.Things which I would love to do with a DSO which would convince me to buy a new one:1. Gated RMS noise measurements. My old Tektronix 2440 DSO does this perfectly. My analog oscilloscopes also do it perfectly, albeit not as easily. Some modern DSOs that I have tested simply return the wrong results, maybe from making the RMS measurement on the processed display record?2. FFT noise density measurements - some very high end DSOs can do this, and as pointed out to me, many R&S models, although I am not clear how far this extends into their lower end models. I need to do a survey.3. Frequency and phase response measurements - sorry, the current Bode plot thing is a joke, and not even a good implementation of a swept measurement. I want the superior FFT version which operates in real time. Some old DSOs support this, but I will probably have to give up and buy a dedicated low frequency network analyzer for this, which is a shame because it should be so easy on a DSO. Again some R&S models might support this, and LeCroy high end models.

author: BirdManPhil
author_rank: Contributor
timestamp: June 18, 2024, 07:35:38 pm
content: I just bought a sds804x this morning after a long hard look at available scopes under $1000 and I can't wait for it to arrive

author: TomKatt
author_rank: Frequent Contributor
timestamp: June 18, 2024, 08:05:11 pm
content: Quote from: David Hess on June 18, 2024, 07:29:25 pmMy HP 180A is evidence that 'good' vintage gear was designed to last longer than equipment built today... I can't recall the exact year mine was built but I believe it heralds from 1968 or '69. The only service I've done was to replace the power supply filter caps, which ended up testing fine - I don't think they even needed to be replaced. I highly doubt any modern equipment will have a service life approaching that - in addition to build quality, their relative simplicity also helps their reliability. And if it does ever require service, it's often much easier to repair (provided parts are available). But the problem is that this gear continues to age, so all things being equal they may now have roughly equal service life remaining.And though many people including myself 'look' at waveforms displayed on a CRO, you are often also doing some rough measuring on the graticule - whether that's amplitude or frequency... Though you may not need the precision offered by modern scope automated measurements, they often are quicker and more accurate than measurements done by eye.

author: 2N3055
author_rank: Super Contributor
timestamp: June 18, 2024, 08:15:59 pm
content: Quote from: David Hess on June 18, 2024, 07:29:25 pmFirst, they don't have to operate that long. New 12 bit 400USD scopes are running circles around many scopes that cost 3000-4000 USD until few years ago. Nobody (except hobby users) wants that old stuff anymore. I would replace it for better, larger screens and much smaller space used on desk alone.And that old, long running equipment, when was new had comparative cost so high that you could easily buy 20-30 new SDS800XHD for equivalent money today.It is same as someone told me: That Brymen BM869S looks very good and is much more capable meter than Fluke 87V. But does it have lifetime warranty? My response: "I can buy 3 BM869 for the price of one F87V.. There is your lifetime warranty...."

author: DimitriP
author_rank: Super Contributor
timestamp: June 18, 2024, 08:39:36 pm
content: With all the features and capabilities, a 747's cockpit worth of instrumentation on one screen.....and for some reason no Timebase Ref input !!!!

author: 2N3055
author_rank: Super Contributor
timestamp: June 18, 2024, 10:05:32 pm
content: Quote from: DimitriP on June 18, 2024, 08:39:36 pmAre you talking about Keysight 20000 USD MSOX3104T scope?

author: DimitriP
author_rank: Super Contributor
timestamp: June 19, 2024, 12:29:06 am
content: Naaaahhh....20K don't get you a timebase input , not "high end" enough! ....28K does !!https://docs.keysight.com/kkbopen/which-keysight-oscilloscopes-have-a-10-mhz-reference-input-output-589306518.htmlQuote