To spend or not to spend - Buying an older analogue 'scope - Page 1
Forum section: electronics / testgear

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 05:37:33 pm
content: Firstly let me say hello!I found this blog from watching Dave's vids on Youtube whilst researching oscilloscopes. I've used a Fluke Scopemeter 123 for a few years now but it's died on me. I've been toying with getting a 'proper; bench 'scope for a while now and it looks like then decision had been made for me!I appreciate "which scope" questions are like "how long is a piece of string" but I've tried to nail down a price point and I'm hoping you guys can add you two cents.After watching a few vids and reading a lot more entries on here I've pretty much decided to get a new digital scope, namely the Rigol 1074z. I was all for the 1052e but I understand the 1074z is a better unit (bigger screen, higher bw). ATM 1074z out of stock here in the UK and won't be in for 3 weeks or so. So thats the Digital scope sorted.One thing that kept getting mentioned in the vids and posts was that its a good idea to get hold or a half decent dual channel 20MHz analogue scope. I can see the attraction and as someone who's never learned on a traditional scope its a route I'm interested in. So I started looking on the bay and yep, there are some older scopes out there for varying amounts.Now here's the question - I can get something battered about, without probes and with no guarantee of correct operation for £50 - £100. Then the next level seems to be Tektronix/Hameg/Hitatchi which can range from £100 upwards. The Fluke/Phillips and HP/Agilent units look to be from £200 upwards. I fully appreciate you get what you pay for and as someone who would rather spend a little more for a better/more reliable product I don't mind getting my hand a little deeper into my pocket for the right unit. Obviously there is a trade off; I'm not about to invest in a mainframe system or something costing megabucks. The other trade off is that I'm pretty much a hobbyist as far as scope duties go, I'm more used to a multimeter in my day job so I don't need all singing and dancing but I would like the best bang for my buck (sorry, perhaps not the best description!)So I've sort of set my price ceiling at around £200 - £250. This looks a lot compared to what I've seen some posters getting hold or good quality scopes for but here in the UK they still seem to hold their value. For once I want to buy something thats fully operational and I'd rather not be fixing it every five mins.I've seen a LeCroy 9400 (2ch,125MHz) in my price range (just). I see that this is a 'good' brand, good value for money? Compared to say, HP/Agilent 54600B (4ch,100MHz)? The The Tek/Hameg/Hitatchi models are cheaper but not by THAT much in the bigger scheme of things. Is it worth the extra for a newer & better spec'ed scope? Are the HP's more reliable generally speaking?BTW I mostly do audio work; synths, eq's etc, both building and repairing. Starting to design stuff too hence the importance in getting the 'Right' scope. I don't want to start out with a cheapo unit that I'm gonna end up upgrading 12 months down the line, I'll be buying to keep event though I hope to have a Rigol by then too.Anyway, thats enough questions from me, over to you guys!

author: linux-works
author_rank: Super Contributor
timestamp: March 21, 2014, 05:54:05 pm
content: not sure how useful storage scopes (rigol) will be to an audio guy. I'm also an audio guy (but I do digital stuff as well as analog and the storage is nice to look at spi or i2c or stuff like that).if you want to see real waveforms, risetimes, etc; the digital scopes are utter crap. they won't show real waveform quality; they sample at 8bit (!) vertical and that is just crap to show real wave geometry.I was going along the lines of the fancy rigol but decided to put my money into the tek 2465b as my ultimate 4ch analog scope. I bought mine for less than the rigol, it has no software bugs, it has time proven hardware and is fixable, which I can't say about imported chinese gear.the tiny 2ch rigol is a good bargain if you want to have as storage scope around. but I'd put more money toward an analog scope, and a real brand one, too. you will have to increase your budget but if you want to 'buy once' then buy the best and avoid having to rebuy and sell to inch your way up the ladder.I do not regret getting that tek scope. there's a saying 'a man who buys the best will not have 2nd thoughts later on'. if you buy a lower end scope, you may be wondering if the better one would have been the wiser choice, later on.

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 06:06:32 pm
content: Quote from: linux-works on March 21, 2014, 05:54:05 pmMany thanks for your input! Thats useful info and food for thought. The choice of models and specs can get a bit overwhelming and reading review after review doesn't help! I was hoping I'd get close to what I wanted with a HP or Fluke 4ch (c £250). What would you say I should be looking at in terms of spec's and models for audio work?ps when I say buy once I appreciate like any bit of kit something could fail making repair prohibitively expensive (and I guess some brands are more susceptible than others as far as obsolete chips/parts go.) I think I was trying to say I didn't want to get a 'beginners' scope with few features only to have to move it on and go shopping again fairly soon.Thanks again

author: linux-works
author_rank: Super Contributor
timestamp: March 21, 2014, 06:25:35 pm
content: when considering the chinese import stuff (ie, not with a company presence in your country) you have to consider the total cost of ownership. purchase price is just one of the components in that.will I bet able to get this repaired? is it cost effective to do that? how much down time could that be and what will that cost my project, in terms of cascading delays. frustration dealing with remote companies and mailing costs/delays. is the documentation sufficient and even, is it accurate? how is the software quality? these days, things are mostly software (for time and effort in design). do they stand behind their product and release frequent updates? do they EOL a product line too quickly? is there a user community for this vendor and this product?to me, when I asked all that (and more), the higher priced chinese stuff did not seem to be a good value to me. I went with an older known brand and even a special model series (some believe it is).but I do own both. the small 2ch 50/100mhz rigol, which is a hell of a value for its price; and also a few tek's that are quality analog scopes and I can trust that what I see on the display is what is present on the wire. the rigol shows me timing and relationships and general wave types, but I can't trust low end or even mid end digital when I want to see the wave form shape and quality.if I was a company and had a formal budget and could 'expense' the equipment (expense is a verb here; odd that it can be a noun or a verb, lol) then I don't care about repair costs or future support. I've figured that the scope should last the duration of the project and project lifetimes in today's companies are pretty short. at the end of the interval, the equipment gets expensed out and sold as surplus. no company cares about long-term support on lower and middle end test gear. you have a support period, you get support (and pay for it) and you change gear when it makes sense, next interval.for hobbiests, we don't live like thatwe want our stuff to run a long time and be fixable. don't we? we don't have that corporate mentality of 'expensing' things out. and so, to us, being fixable and supportable longer term is a key point in the decision.

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 06:30:16 pm
content: Couldn't agree more. I can see now that an analogue scope should be my priority and when I've got a few more quid I'll get hold of a Rigol. So the hunt begins in earnest for a scope….

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 06:34:37 pm
content: Here in the UK Tek 2465 £700 and a 400 mile round trip. I may have to set my sights lower..

author: linux-works
author_rank: Super Contributor
timestamp: March 21, 2014, 06:38:40 pm
content: out of your scope price budget, you really only have about halfyou have 1x for the scope and about 1x for misc probes. if 4ch scope, 4 probes can cost as much as the damned scope! if you want active fet probes, figure another $200 or more for a pair of them. stuff does add up.for logic analysis, where I want lots of channels but they won't be analog, ever, I use the cheap $50 cards that interface with usb and break out logic. that does not have to be on my 'scope'.a 4ch rigol sounds nice, but I get multichannel via the logic sniffer. so I only really need 2ch digital. and that was met by the infamous 50/100mhz 2ch rigol. its cheap enough and small enough to justify itself on your bench. and if it breaks or dies, its not the end of the world. it gives me 100mhz of reasonable digital capture on 2ch.on the analog scope, that's where I wanted a bit higher bw. the tek 2465 series is a 300-400mhz scope that is built to a quality level you don't see anymore. they don't cost that much, they do give an accurate view of what's on the wire, and they have a great support community. that's just one example, you will have to look around to see what suits you.in terms of how much to split things, I went more toward the analog scope side (and its probes) and less on the digital scope side.

author: linux-works
author_rank: Super Contributor
timestamp: March 21, 2014, 06:42:23 pm
content: Quote from: Bunk on March 21, 2014, 06:34:37 pmthat's a lot of money. can't comment on the drive; I had a friend in holland make a day drive to pick up some guy's DIY spkrshe said it was a nice drive and he didn't mind it, and was glad to get the 'gear'.here, those scopes are $400 - $600, with stuff higher and lower too, of course. I'm seeing a lot of the base model, at least (2465, not A or B) at my local store and its just sitting there for months and months.there is the lower bandwidth version, if that is any easier for you to find locally. 2445 I think is the number. its very similar and just a 'limited' version of the 2465 series. its still quite fast and has that really nice tek user interface.

author: KJDS
author_rank: Super Contributor
timestamp: March 21, 2014, 06:45:58 pm
content: Quote from: Bunk on March 21, 2014, 06:34:37 pm£700 is too much for a 2465. I'll have a rummage down the back of my storage unit at the weekend and see what I can find.

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 06:53:10 pm
content: The 2225 models seem to be more common, and are below my budget. But I'd deffo pay the extra for a better featured model if the price was right (and so was the scope!)

author: G0HZU
author_rank: Super Contributor
timestamp: March 21, 2014, 08:07:19 pm
content: My advice to anyone is to only buy stuff you have a genuine need for. Only put stuff on your test bench if it can earn its keep and justify its footprint and its purchase price and power consumption and any annoying noise it makes when running.High BW analogue scopes like the 2465 aren't made any more by the main scope players for a very good reason. Hardly anyone in the modern electronics industry needs or wants one. Iwatsu still make them but only for a limited market.So don't get romanced into buying an expensive trophy scope that you probably don't need... especially something as old and expensive as a Tek2465.If you are just playing with audio, my advice would be to buy a very basic 2 channel scope with about 20MHz BW. Try and find one that goes down to about 500uV/div. Often this sensitivity is achieved with a x10 button and a huge reduction in bandwidth to maybe 500kHz at this gain setting. But it gives a low noise trace for audio work if you want to look at audio signals at a few millivolts.A £50 scope can be considered disposable if it goes wrong or you can buy another one of the same type for £50 and keep the old one for spares.Also, I'd suggest getting a basic 192kHz sound card + suitable external interface to act as an alternative scope for use up to about 80kHz if you want to look at distortion etc. Then put the money you have saved towards a half decent digital scope at some point in the future if you want a general purpose modern scope.

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 08:21:27 pm
content: Thanks or the advice! I'm still at the weighing up stage. I don't want to 'outgrow' a very basic scope (but for audio that might not be the case with a basic 2ch 20MHz scope?) And I'm worried the older cheaper models will have burned screens, wildly out of calibration/faulty and will be in a generally rough state. Now if that was a synth we were talking about, bring it on! But when it comes to something like a scope I want the best for my money.I'm happy with the look or the Rigol for when I want to invest in a digital scope.

author: linux-works
author_rank: Super Contributor
timestamp: March 21, 2014, 08:42:16 pm
content: the 2465 is a lot of scope and its 'more than you need' for audio. but its build quality is impossible to find today and it IS repairable. you are not at the mercy of some vendor. that's my point. its overkill on this model but pick a model that you like (for audio, the 2225 is great and not too expensive. no reason not to have it as your first scope).and for audio, wave quality does matter. I want to see what's there and not some dotty lcd version of what some a/d thinks is there.there is a reason that people still seek the older analog scopes. if you can afford the best digital, that's fine. it did not seem that the OP was in that groupingand so, a damned good analog and an 'ok' digital is what I'm trying to recommend, using my own scope model only as an example.

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 08:53:34 pm
content: I'm liking the look of the 2225. Plus I'll have a few quid left over to upgrade the probes (if required)

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 08:58:11 pm
content: Quote from advert. "For Sale a used TEKTRONIX 2225 - 50 MHz Dual channel OscilloscopeThe Oscilloscope has been tested and FULLY calibrated and all functions work properly as intended.This scope has some special features, including time base expansion at 5X, 10X, and 50X - which in effect gives dual time base functionality. 10X expansion on the channel amplifiers effectively gives 0.5 mv /cm sensitivity"£175.

author: linux-works
author_rank: Super Contributor
timestamp: March 21, 2014, 09:12:12 pm
content: its a bit expensive in US dollars, but I really do like this scope. fanless, very low noise (perfect for audio) and light weight. once dave reviewed it, the used price went up. the dave-dot effect, as it wereI have a 2225:can you go visit it and try it out? also, if probes come with it, great. else, 50mhz is not 'hard' to find probes for, even good used NOS tek probes.

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 09:18:52 pm
content: Thats a nice looking stand too!the rest of the description"For Sale a used TEKTRONIX 2225 - 50 MHz Dual channel OscilloscopeThe Oscilloscope has been tested and FULLY calibrated and all functions work properly as intended.This scope has some special features, including time base expansion at 5X, 10X, and 50X - which in effect gives dual time base functionality. 10X expansion on the channel amplifiers effectively gives 0.5 mv /cm sensitivity !Both Channels and the Timebase has been checked and calibrated against a highly accurate signal generators/scope calibrator and works to spec. on all switch settingsAll Switches have been check for proper operation.For good measure common components which age and cause failure over time or cause bad/fuzzy display have been replaced.You will see a lot of scopes on EBay that “sort of work” and display something; But if you need an instrument that will take accurate measurements of the displayed signal, and be able to use all its functions, then you need a scope that has been tested and calibrated.This Scope is EXACLY THAT.The traces are bright and PIN sharp.Supplied with Mains lead, and one 10x switchable 100 MHz probe.If you have any questions then feel free to contact me."There is another model at £125 (different seller) without probes.A third is also up for bidding, again without probes.The first seller looks the best of the three, plenty of pics, good feedback, honest looking item and listing.

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 09:32:42 pm
content: He's happy to demonstrate but again it's a bit far for me. He will send via a courier though. Price wise is around the price that other similar condition models are selling for. The market looks quite strong for some brands, Tek being one of them.

author: G0HZU
author_rank: Super Contributor
timestamp: March 21, 2014, 09:52:35 pm
content: For the limited front panel features it offers it seems a bit expensive to me but it does look like a neat little scopeI think I'd rather buy/risk an old Tek 465 and have >£100 in change. I bought my 465 way back in the 1990s for £52. But it isn't going to be as reliable as that 2225 scope I guess...For audio work you can probably find someone to virtually give you an unwanted 30MHz scope. I don't really want to part with my old Solartron Schlumberger A100 scope but it was made in the early 1970s and can do more than the Tek 2225 and I doubt it would fetch £10 if I sold it on ebay. I think I paid £30 for it in 1990. It's basically worthless now but it would be just as good as the Tek for basic audio testing.

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 10:00:55 pm
content: Thanks for your input too! I have looked at some of the old Tek 4xx's but it was the age and the reliability that put me off a little. There will be some gems out there but I think I might end up going through a few until I find a 'good' one, if that makes sense? The same applies to the later models but to a slightly lesser extent as they haven't been around as long and theoretically have less hours on them (on average).

author: G0HZU
author_rank: Super Contributor
timestamp: March 21, 2014, 10:11:03 pm
content: I dug out the A100 and stuck it on a bench and powered it up.Here it is being fed just over 5mV rms from a sig gen at 10kHz. It also has a x10 function on CH1 so it can amplifiy this ten times more if required.So this kind of represents the bottom of the barrel in terms of cost for a scope. It's probably worthless in 2014 but I think it would be just as good as the 2225 for simple audio workSomebody, somewhere will have a scope like this that will be free to collector. I've seen far better scopes than this offered free on this forum alone

author: G0HZU
author_rank: Super Contributor
timestamp: March 21, 2014, 10:20:25 pm
content: I tried the A100 with the x10 amplifier and took it down to about 150uV rms and it was way, way better at measuring the voltage of the 10kHz sine wave than my Keithley 2015 at this level.The modern 6.5 digit Keithley 2015 crashes out in this test because it's way too noisy. My Tek TDS2012 digital scope was hopeless here too.

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 10:20:43 pm
content: Many thanks for going to the trouble of setting up and photographing! Thats a very nice looking scope too!

author: Bunk
author_rank: Contributor
timestamp: March 21, 2014, 10:24:52 pm
content: Oh and in far better condition than most of the older scopes Ive seen on the bay recently. In fact I'd go so far as to say you'd probably get more than you think on there at the moment!

author: KJDS
author_rank: Super Contributor
timestamp: March 21, 2014, 10:37:16 pm
content: I suspect you'd get reasonable money for that A100, it would certainly go for more than £50 on ebay with a good advert. Have a look at this one to see what another old scope made in an auction.http://www.ebay.co.uk/itm/Hitachi-V212-20MHz-2-channel-analogue-Oscilloscope-/321322810982?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item4ad054fe66&nma=true&si=Qk3NuxJdPhj%252BRlm5JDz4DMOfqhA%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

author: grumpydoc
author_rank: Super Contributor
timestamp: March 21, 2014, 10:49:20 pm
content: http://www.ebay.co.uk/itm/Tektronix-2225-50-MHz-Oscilloscope-/271431135707?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item3f328e71dbNot my auction.I have a Hitachi V1565 on ebay at the moment and a few 2235's (100MHz dual time base) at least one of which I should get listed next week.

author: G0HZU
author_rank: Super Contributor
timestamp: March 21, 2014, 11:38:15 pm
content: Well I guess there is no 'one size fits all' answer to this type of queryI think you have to try and predict what you want to do with the scope in the future...If you ever want to tinker with radios and and ham stuff then I think you need to be looking at a decent >=100MHz analogue scope. The 2225 is going to run out of breath a few times here... The 30MHz A100 would be of very limited use here and is pretty much obsolete in this respect.The people who most often dish out for the 400MHz 2465B are the more serious ones in the above category, especially if they do it as a business or they do repairs for other people at home.Most hobbyists who don't fall into the above category will be better off with a digital scope, especially when it comes to debugging digital stuff. eg for looking at serial data and microcontroller based stuff. You can also look at distortion on a reasonable digital scope. eg my old 8 bit TDS2012 is quite useful in the FFT mode. So it can be useful for audio work for measuring moderate levels of distortion.If you just want to look at audio waveforms then either use a USB scope or a soundcard scope or get something old (but good) and cheap.QuoteYou are probably right. Maybe a keen collector would want it but I think its true value (from a technical and practical point of view in 2014) is close to zero

author: RRobot
author_rank: Regular Contributor
timestamp: March 22, 2014, 12:01:33 am
content: My only analog scope, a 400MHz 2465B, quite working a year and a half ago.I had planned on fixing it and it had a place beside my Agilent MSO7000 while it worked (although it was rarely turned on) and stayed there for a month or two after it broke.Later I needed the room for some other equipment so I moved it to another shelf where it has sat for all of this time. Lately I've been thinking off packing it up altogether.I still plan on fixing it one day, it was a fantastic scope, but basically I'm saying I have not missed it at all since it broke and don't really plan on replacing it with another analog if I don't get it working.

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 09:07:55 am
content: Thanks for your input here guys.Am I right in saying a digital scope (at the price point I'm looking at) won't be very good, if usable at all, for the sort of stuff I do? I don't see myself getting into ham or radio stuff and my work on digital circuits is pretty much non existent too. I mainly need the scope for calibrating and faultfinding well within the 20MHz range. VCO Triangle wave/sine wave symmetry, Looking at envelopes over several seconds etc. Its pretty much basic audio with a distinct slant toward analogue synths. F/X etc.I don't want to buy a super high end digital scope if a simpler analogue scope is all I need. So my train of thought was get the best scope you can for the money rather than something that might be breaking down every other week or that is that battered that it can't be relied on to give accurate and repeatable results.If I do end up going more digital (which will prob happen one day) then I'll reassess what I need and prob go for one of the newer digitals like the Rigol but in the meantime I'll need an analogue scope I think?Cheers!

author: MarkL
author_rank: Unknown
timestamp: March 22, 2014, 12:51:22 pm
content: The examples you gave of looking at waveform envelopes and sine/triangle symmetry are both better suited for digital scopes.For seconds long envelopes you're going to want similarly long sweep times. You can keep the picture in your mind, but the waveform is not going to persist on an analog screen. On digital, you can set a long sweep with peak detect mode and you'll have the resulting envelope on the screen where you can also take measurements on it.For adjusting distortions such as asymmetry out of waveforms, a digital FFT will show nuances you can't possibly see on an analog scope (or on a digital scope in regular Y vs. time mode, for that matter).

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 01:51:56 pm
content: Thanks for you comments Mark. Now I am confused, especially as a previous poster said this.."not sure how useful storage scopes (rigol) will be to an audio guy. I'm also an audio guy (but I do digital stuff as well as analog and the storage is nice to look at spi or i2c or stuff like that).if you want to see real waveforms, risetimes, etc; the digital scopes are utter crap. they won't show real waveform quality; they sample at 8bit (!) vertical and that is just crap to show real wave geometry.I was going along the lines of the fancy rigol but decided to put my money into the tek 2465b as my ultimate 4ch analog scope. I bought mine for less than the rigol, it has no software bugs, it has time proven hardware and is fixable, which I can't say about imported chinese gear.the tiny 2ch rigol is a good bargain if you want to have as storage scope around. but I'd put more money toward an analog scope, and a real brand one, too. you will have to increase your budget but if you want to 'buy once' then buy the best and avoid having to rebuy and sell to inch your way up the ladder.I do not regret getting that tek scope. there's a saying 'a man who buys the best will not have 2nd thoughts later on'. if you buy a lower end scope, you may be wondering if the better one would have been the wiser choice, later on."From that I understood divi scopes aren't suited to audio?

author: oldway
author_rank: Super Contributor
timestamp: March 22, 2014, 02:25:28 pm
content: 20Mhz is enough for audio applications but there is a great difference of quality and technology between an analog scope of 20Mhz bandwith and a 100Mhz one.Analog scopes of 100Mhz and more are "industrial" grade....I repaired a lot of analog scopes of various brands and I have :1) Tektronix:- 01 scope 2235 100Mhz (working) - NB: modified with fan.- 01 scope 2236 100Mhz (working)2) HP:- 01 HP1740A 100Mhz (working)- 01 HP1740A 100Mhz (not working, for parts)- 01 HP1725A 275Mhz (working)- 01 HP1715A 200Mhz (not working, for parts)3) Hameg:- 02 HM605 60Mhz (working)- 01 HM1005 100Mhz (working)- 01 HM1505 150Mhz (working)4) Philips:PM3233 10Mhz (Working - 2 beams - long decay phosphor)They all are great scopes, but my working horse is : HM605 (with component tester very useful for repair and diagnose)I think that HM605 is the best of Hameg analog scopes.HM1005 would be the best, but it has no component tester.Hameg scopes are easy to repair and I think it is the best choice for you.

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 02:31:52 pm
content: Thanks for that info. I was looking at the Hameg scopes albeit it was the 20x models that I saw for sale. How do the 203/206 models compare?There is a 605 for sale quite close to me but it looks to be faulty sadly. Problem with the focus and no probes which isn't that big an issue.http://www.ebay.co.uk/itm/Hameg-HM605-60MHz-Oscilloscope-/321352883316?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item4ad21fdc74

author: oldway
author_rank: Super Contributor
timestamp: March 22, 2014, 02:43:27 pm
content: Price difference between HM605 and HM20x is not that much....But HM605 is far better ....Don't spend you money buying other Hameg analog scope than HM605 or HM1005.I have a frequency counter ( HP 5315A) connected to the vert output of the rear panel so I can measure frequency of input signal with precision.QuoteSeems to be a high frequency oscillation of the final vert. amplifier, not a focus problem.

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 02:53:12 pm
content: Thanks! Shame that ones faulty.

author: linux-works
author_rank: Super Contributor
timestamp: March 22, 2014, 03:04:45 pm
content: if you mean analog audio, of course you want an analog scope.in my audio work, I want to see high freq oscillation. hard to see that on low res digital. I want to see fine noise levels and noise riding on a signal. can't do that on digital; the wave is so noisy on a pure sine, you can't TELL what is really going on.if I put the input to ch1 and output to ch2 and subtract them, I want to see diffs and again, digital wont' show that well enough.what I do use digital for is to capture short pulses or digital busses. but for analog amps and oscillators and psus, I use only analog scopes.for serious digital work, I'll use a logic analyser with 8 or 16 max inputs. the digital scope is a middle ground piece of gear (at our price levels; that's an important point) and I find very little actual use for it, day to day. if we are talking $50k, sure, you no longer need an analog scope but that's not what you or I could afford to buy. in the $5k and less range (maybe even 10k and less) the digital scopes are not at all a replacement for analog when you are DOING analog work on your circuit.

author: nctnico
author_rank: Super Contributor
timestamp: March 22, 2014, 03:17:44 pm
content: Quote from: linux-works on March 22, 2014, 03:04:45 pmCrap. The vertical accuracy of a scope is a few percent. So sampling with 8 bits is more than enough. Just get a digital scope and don't mess around with old junk analog scopes. How old are 2465s by now? 30 years? more? They are big and produce a lot of heat -if they work-. Besides that a digital scope also allows to look at low frequency waveforms. Impossible with an analog scope without getting a headache. Digital scopes also have FFT which is usefull to look at distortion. You won't see -30dB 2nd order harmonic distortion from a waveform but the FFT will show it (with the scope set to high resolution).If you are serious about audio get an AC voltmeter (preferably one with a double readout) and a distortion analyser.

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 03:19:38 pm
content: Thanks for clearing that up Linux-works. Yeah its analogue audio (VCO's, VCF's etc) and Control Voltages.

author: linux-works
author_rank: Super Contributor
timestamp: March 22, 2014, 03:31:51 pm
content: do you plan to do digital design or debug? i2c, spi, serial, stuff like that?those are the only good apps I can think of for a lower end digital scope for an analog person.I like putting sines and triangles and squares into amps and seeing what comes out. can't make any quality judgements if the scope is digital. yes, it looks like a square, but those noise bumps on the wave, is that the scope or my actual signal? things like that are why I don't recommend digital scopes for stuff like this.the one huge benefit of a new digital scope is that its cheap to buy and comes new, tested (in theory) and you have some kind of warranty. but the display output style is just not high enough res to make judgements about analog waveform quality or noise levels or distortion levels.ok, one more thing the digital scope is great at, for audio: most have built in spectrum displays and so you can see if you have harmonics or not. that IS very useful to have and even a low end digital can do that.otoh, a good sound card and software can do it even better! with a sound card you have 24bit (in theory) vertical resolution. more like 18 to 20 real bits but still, WAY more than 8bits you get from affordable digital scopes. I use the esi juli@ sound card (test gear quality level; highly recommended) or the emu0404 or the m-audio firewire a/d/a boxes. all are measurement quality for high end audio and you can run free RMAA software for lots of audio testing.

author: PlainName
author_rank: Super Contributor
timestamp: March 22, 2014, 03:34:13 pm
content: Quote from: Bunk on March 21, 2014, 08:21:27 pmWe all do for everything, but your problem is you don't know what you want and you'll end up with what someone else wants.What usually sorts me out in this situation is to go and get something cheap and reasonably capable as a technology demo. I use it, and in using it I find out what I want and need, and then I go and spend the proper money on the right thing.For instance, we needed a brushcutter (not an electronic item, your honour) and had not a clue about which or what, so I got a cheap one from a local shop having a sale. Cost about £40 IIRC. It was rubbish, but in using it we found out why it was rubbish, so when it finally died we knew that the next on would have a geared joint at the business end instead of bent flexible drive. It would have to be startable in situ rather than having to take it off to do that. Etc. We wound up with a Stihl that's done many years service and which we love to bits, but had we not got the rubbish one first we'd probably not have realised why the Stihl is so much better, and got a not-quite-so-cheap one that was still rubbish.Strangely, we had the rubbish one dismantled on a bench (the motor seized) when we had a break-in one night. The only thing the perps nicked was this dismantled rubbish strimmer...Er, so in your position I wouldn't bother about getting something that will suit me down to the ground in 5 years. I would get something that will work sufficiently well right now and which I will replace next year having figured out what I want by then. A 20MHz analog job might be great for audio work, and if I haven't learned why 20MHz is a serious limitation by next year I don't need the 1GHz HP after all.

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 03:37:37 pm
content: At some time in the future I might start messing with I2C etc but not yet.I don't have a PC so that options a bit of a non starter for me.

author: sync
author_rank: Frequent Contributor
timestamp: March 22, 2014, 03:42:56 pm
content: An analog scope is not good for low frequency stuff, e.g. an envelope control voltage. You only see a moving dot. Not a trace.About the 2465 are fixable. These are full of custom hybrids which are unobtanium. If one of them fails it's likely game over. The famous U800 is a common problem and the 2465B has problems with leaking caps which can destroy the PCB.

author: Nerull
author_rank: Frequent Contributor
timestamp: March 22, 2014, 03:54:20 pm
content: Quote from: Bunk on March 22, 2014, 01:51:56 pmSome people have very strong opinions which aren't really based on all that much evidence.Those 'fixable' teks are loaded with custom proprietary unobtanium parts. They are reliable, but there isn't a lot of fixing to be done for many failures.

author: linux-works
author_rank: Super Contributor
timestamp: March 22, 2014, 03:54:57 pm
content: I would counter that: hybrid parts are buyable, but not cheaply. still, you rarely have to junk the whole scope. a tds, otoh, you will likely junk the whole thing since its all custom and not enough of those chips (etc) are on the used market.2465: lots of used BOARDS on the market, crt displays, etc. even knobs and front panels. its fixable.true about the slow moving envelopes. that would be a good use for a capture (digital). or, if its really slow moving, a good DMM with scpi or equiv interface and a pc to poll it for values, then graph it. that will give you a far better and more accurate view of slow changing things.

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 03:55:53 pm
content: Quote from: dunkemhigh on March 22, 2014, 03:34:13 pmYou're right I don't know what I want and thats why I'm trying to figure out what I need. I know what i want to use the scope for tho. Calibrating oscillators, keyboard controllers, VCF's etc; fault finding in said circuits and similar. No digital domain stuff, purely sub 20kHz audio work.I've played that game of buying stuff, finding out its not what I want or generally growing out of it, then upgrading. I'm trying to avoid that and I was hoping by listing my requirements (which seem pretty limited and simple) I'd get pointed in the right general direction. Sorry if I didn't make that clear.When it comes to the higher BW models that have been discussed its purely been from the point of quality and second hand price. If, for a smallish amount more than I would pay for a bog standard scope I can get a much model with better long term reliability well then I don't mind paying the extra. It'll still do what I want but it'll be a better unit to own longterm.If you compare it to cars I could buy a little french hatch back to ferry myself and my tools about. It'll do the job; its got a wheel at each corner, a hand full of doors and an engine. For a little more I can buy a similar aged Volkswagen Golf (Rabbit in US) that will go and stop better and fail less than the cheap hatchback. (Before I start another argument I speak from experience of owning both cars! And I still have the Golf)

author: oldway
author_rank: Super Contributor
timestamp: March 22, 2014, 03:57:07 pm
content: Buying a good quality analog scope can't be wrong.With such a scope, you can do a lot of work.They are becaming scarse and if you want to resell it in 5 years, perhaps you will win money.Hameg is still furnishing spare parts for their older analog scopes.HM605 and HM1005 don't have any sophisticated digital circuits, nor non commercial parts, its very easy to repair.For example, the HP1725A is a very good scope, but it as an hybrid final vertical amplifier that often fail and that is not to find anymore.The same problem with Tektronix 2445/2465 with Horiz amplifier U800.If these parts fail, you can't repair your scope.

author: linux-works
author_rank: Super Contributor
timestamp: March 22, 2014, 03:57:54 pm
content: Quote from: Nerull on March 22, 2014, 03:54:20 pmtell that to the yahoo scopes group, who regularly help people fix their so-called 'unfixable' tek analog scopes.the custom parts are available and boards are, too. its not nearly the problem you make it out to be and its unfair to make people think these are dead-end scopes. that's not even close to the truth and is intellectually dishonest of you to say such things.you are not going to be able to find the custom tek parts at frys or radio shack or even mouser, but they are buyable on ebay or custom tek shops (qserver in greece, for example) and there are enough guys still around who WILL work on these scopes for a flat fee and get it working again.how many techs will fix broken digital tek scopes or rigols? yeah, right.

author: linux-works
author_rank: Super Contributor
timestamp: March 22, 2014, 04:03:57 pm
content: there is an experimental u800 replacement board that some guys have been working on, entirely on their own.the chip can still be bought in used markets.you can buy 'donor scopes' and steal that board or chip from it.finally, that chip does not usually die on its own, so to hold that chip up as a reason NOT to buy the 2465 is mostly a scare tactic. I was worried about this chip, myself, but after talking with some ex-tek employees (and those in-the-know) this is a tempest in a teacup. they don't fail during normal operation and they aren't the end of the scope as some posters want you to believe.the key is to get an old enough scope so that schematics were released for it and also old enough so that donor models can be found to fix things. donor models can be cheaper than the mailing and waiting and repair bill cost of fixing a modern digital!I am arguing for having both, but I don't understand the 'hate' for the higher end tek analog scopes from the early 90's. they are considered tek's best analog scopes and after some cap refreshes, they will likely go another 20 or 30 yrs before they finally give up. you cannot say that about ANY digital, ever made. I challenge you to find a digital still useful and in operation 20 or 30 yrs after it was sold.digital scopes are short term buys. analog scopes of the tek calibre are investments that will last you your career's worth of time. I got tired of buying and rebuying modern crap and so I did invest in older gear that I could not afford back then at the new price but I surely can, now, at the used price.

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 04:04:35 pm
content: Quote from: sync on March 22, 2014, 03:42:56 pmThats a good point, especially for LFO's too I would guess. So maybe there is a case for both after all!

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 04:10:58 pm
content: oldway makes a good point too. The Hameg manuals you can DL from their site include schematics. I'm not that confident poking around high DC voltages in a confined space so I wouldn't fancy embarking on repairs but its good to know they are fairly easy to repair. 50v DC wet cell cubicles can be scary enough, especially with no isolation on the load side!

author: oldway
author_rank: Super Contributor
timestamp: March 22, 2014, 04:14:18 pm
content: Quote from: Bunk on March 22, 2014, 04:04:35 pmFor this application (low frequency stuff), you can choose a P7 phosphor crt.I have a PM3233 Philips with such P7 phosphor I use as curve tracer.NB: HM605 is also available with P7 phosphor instead of P31.

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 04:17:59 pm
content: Sounds good, especially if that means I can do the LF stuff without the initial outlay of 2 units. Thanks.

author: nctnico
author_rank: Super Contributor
timestamp: March 22, 2014, 04:19:48 pm
content: Quote from: oldway on March 22, 2014, 03:57:07 pmYou could always come up with an alternative. I have fitted an HP800 series scope with a completely new 300MHz front end because the old one was build around a piece of unobtanium.@linux-works: there are lots of people fixing TDS scopes. Especially the 500, 600 and 700 series. I fixed a few myself. Depending on the problem I don't see why you wouldn't be able to fix a Rigol scope. There are so many teardowns of those that the inner workings are very well known.

author: oldway
author_rank: Super Contributor
timestamp: March 22, 2014, 04:21:27 pm
content: Quote from: Bunk on March 22, 2014, 04:17:59 pmCRT's with P7 phosphor have a yellow plastic shield instead of a green one.This is an Hameg HM605 with P7 phosphor:http://commons.wikimedia.org/wiki/File:HAMEG_HM_605_60_MHz_Oscilloscope.jpgAnd this is another HM605 but with a P31 phosphor.http://www.radiomuseum.org/r/hameg_oscilloscope_60_mhz_hm605.html

author: sync
author_rank: Frequent Contributor
timestamp: March 22, 2014, 04:24:01 pm
content: Quote from: Bunk on March 22, 2014, 04:04:35 pmYes.But there are cases where an analog scope is better than a low-end digital one. For example looking at a modulated signal from a VCO or VCF. Look at my posts in this thread:https://www.eevblog.com/forum/testgear/hello-looking-for-small-digital-oscilloscope-for-use-with-analog-synthesizer/For analog synth stuff a 50$ dual channel 20MHz analog scope is enough. No need for a high-end analog one. Make sure you can get the service manual with schematic for it.

author: sync
author_rank: Frequent Contributor
timestamp: March 22, 2014, 04:25:38 pm
content: Quote from: oldway on March 22, 2014, 04:14:18 pmHow good is P7 for fast changing waveforms?

author: linux-works
author_rank: Super Contributor
timestamp: March 22, 2014, 04:28:23 pm
content: are schematics availabe for tds scopes? I have not looked since I was advised to avoid them and they came well after tek stopped releasing schematic and service manuals. the common wisdom (which may be arguable) is that the scopes after the mid 90's are 'not repairable' in any meaningful way. you can fix obvious things, of course, but unless you have a good service manual, there's only so much you can do. these are more meant for corporate consumption than end user hobbiests.I still stand by my statement that tds scopes are to be avoided if you want to invest in them and have them last a long time and be repairable without special abilities (those high density smd chips are not for mere mortals to replace; those scopes are better fixed at the whole board-swap level and that's just not economical).I really like the tek digital scopes, at a certain level; and if someone else was buying and maintaining them for me, I'd be very happy about that! but if its me having to buy and keep them running, that's a total non-starter for me. I just don't recommend others start off with a tek digital. once a corp has expensed it and its beyond support time or warranty time, they are like high end bmw's; not cost effective to fix and best used during the 2-4 yr lease period and then let go after that! its quite a different mentality of buying a modern piece of test gear vs the older classics. modern stuff is not meant to be supported (for repairs) by end users anymore. it will be very frustrating to find that your expensive tek tds is now a dead-end or too expensive to send out to a real tek-qualfied shop.

author: oldway
author_rank: Super Contributor
timestamp: March 22, 2014, 04:29:21 pm
content: Quote from: sync on March 22, 2014, 04:25:38 pmI don't like it...

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: March 22, 2014, 04:42:28 pm
content: tl;dr have you considered a new analog scope? There are still new analog scopes available. I'm sure there are people here that can point the way to those still selling new scopes. I think Hameg does and BK+Precision does and there are others. Instek??

author: sync
author_rank: Frequent Contributor
timestamp: March 22, 2014, 04:43:27 pm
content: Quote from: oldway on March 22, 2014, 04:29:21 pmThen it's not good for analog synth stuff. Maybe an analog/digital combo scope. It has the fidelity in analog mode and for the slow frequency stuff the digital mode. Or a DSO with intensity grading and a decent wfrm/s.

author: sync
author_rank: Frequent Contributor
timestamp: March 22, 2014, 04:47:24 pm
content: Quote from: linux-works on March 22, 2014, 03:54:57 pmOr just buy another working one. The hybrids and boards aren't cheap as you say. Then you need expensive test equipment for the calibration after repair. So buying another one is maybe cheaper.

author: linux-works
author_rank: Super Contributor
timestamp: March 22, 2014, 04:49:45 pm
content: again, for slower moving things that you want to graph, why not just use a dmm that has computer control?you get (time,value) pairs that can be sent to any graph display, even simple spreadsheets can do graphing for this kind of data. you can import into mysql (for example) and so analysis on it. WAY more power than any scope will give you.if the data rate is too high, dmm polling won't work but for slower moving data collection jobs, an rs232 or gpib meter is the best way to do this. and this is why, when it comes to dmm's, I recommend only computer-controllable (serial i/o port on the back) DMMs.

author: nctnico
author_rank: Super Contributor
timestamp: March 22, 2014, 05:03:08 pm
content: Quote from: linux-works on March 22, 2014, 04:28:23 pmThere are schematics available for the TDS500,600 and 700 series. Look for the TDS520B component service manual. Besides that most of the problems are in power electronics and analog inputs. The digital part usually is OK.Then again: you don't buy a scope to fix it but to use it. IMHO you can't go wrong on a cheap Rigol or Siglent scope. I used to have digital/analog scopes (Tek 2230 and an Iwatsu) but in the end I never used the analog mode because the digital mode was much easier to use. And those scopes are from the 80's. Technology has advanced a lot since then.

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 05:07:47 pm
content: Quote from: linux-works on March 22, 2014, 04:49:45 pmI don't have a PC and I don't want one again! (read upgrades, downtime, failures etc etc) I went over to Mac 10yrs ago and I don't want to go back! I know, Mac's don't have the software out there that is available for PC but 99.9% of the time my Mac's do everything I need!

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 05:12:34 pm
content: Quote from: sync on March 22, 2014, 04:24:01 pmi had a look there. thanks for the link!

author: sync
author_rank: Frequent Contributor
timestamp: March 22, 2014, 05:30:06 pm
content: Quote from: linux-works on March 22, 2014, 04:49:45 pmThese slower things can have rise times of a few ms. Look at the attachments. This is the audio out of a note played with an analog synth. Unfortunately it doesn't has outputs for the control voltages. But the envelope of the waveform is one of them. A scope is much more versatile for this. And you maybe want to zoom into the waveform. Here a DSO wins.

author: linux-works
author_rank: Super Contributor
timestamp: March 22, 2014, 05:43:01 pm
content: oh yeah, go ahead and bring fast rise-time into it. lol. on that, yeah, the scope clearly wins as you see fast edges due to fast 'self polling' (the gear is polling instead of the remote pc).this is why you need an array of tools. having just one kind of scope or data logger is not enough, today, unless you have very high end and high priced gear.

author: sync
author_rank: Frequent Contributor
timestamp: March 22, 2014, 06:06:30 pm
content: Yes you need an array of tools. A good analog scope, a good DSO, a few bench DMMs with 1000 samples/s or more and a PC in the lab.Back in the days when I was into synthesizer stuff I only had a very basic 15MHz two channel analog scope and a crappy DMM. It worked. Of course the scope didn't well on the slow things and debugging the microprocessor stuff.I think today I would prefer my Rigol DS1074Z over my analog Tek 2246A for this. But a basic two channel analog scope is enough. A DSO has advantages.

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 06:19:28 pm
content: The 1074z was first on my list to be honest!I know I'm being stubborn about the PC; like everything, I'll end up giving in in the end..

author: MarkL
author_rank: Unknown
timestamp: March 22, 2014, 06:38:28 pm
content: Quote from: Bunk on March 22, 2014, 01:51:56 pmWell, I don't agree with that assessment, or the thing about bits and rise times. Rise times are rise times, analog or digital. And if 8 bits is insufficient, boxcar (aka high res) or waveform averaging is available on many scopes which increases the effective number of bits. Intensity grading on digital displays is also a valuable way to convey additional information on waveform stability. (I would add that, in this regard, the old Tek TDS3000 series had the best emulation of real phosphor, at least in my opinion.)But based on what you were looking to do, my point was that I think you might find more utility in a digital scope. "sync" already posted some photos of envelopes, which I had mentioned, and below is an example of an FFT.The first photo is a 900Hz sine on everyone's favorite analog scope (mine too, by the way). At a glance, it looks pretty good and not worth tweaking.But wait, look at an FFT of the same signal. You can see the main peak at 900Hz in the center. Off to the right, there's a strong peak at the 2nd harmonic indicating there's some asymmetry. And off to the left, a 120Hz peak which could be introduced by the power supply. Now these anomalies are pretty far down from the main signal, and maybe too far down for you to care in your application, but my point is on an analog scope they could be overlooked very easily or be completely invisible no matter how long you stared at it.Admittedly, a scope's FFT doesn't have a lot of dynamic range and it has a lousy noise floor. But it is a useful tool available at the touch of a button on digital scopes.

author: eurofox
author_rank: Unknown
timestamp: March 22, 2014, 06:44:59 pm
content: Hi,I have a Tek 2465 400 Mhz version, I think one of the best analog scope ever build. It trigger up to 2 ns rising edge, below it is not.I was convince that some events can only be visible on an analog scope but since I got my Agilent MSOX3104A I have changed my mind.eurofox

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 06:52:38 pm
content: Thanks for clearing that up Mark and taking the time to take the photo's! I really appreciate all the posts one here, I'm learning a lot!

author: sync
author_rank: Frequent Contributor
timestamp: March 22, 2014, 06:58:28 pm
content: Quote from: Bunk on March 22, 2014, 06:19:28 pmThen buy it!It's the cheapest DSO for this kind of stuff. It doesn't have a great fidelity. But analog synths aren't high fidelity anyway. It has more advantages than an analog one.Don't buy a cheaper DSO like the Rigol DS1052E. You will need intensity grading and a high waveform update rate for an analog like display.

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 07:07:43 pm
content: The intensity graded display was one of the main selling points of me after watching Dave's video.

author: linux-works
author_rank: Super Contributor
timestamp: March 22, 2014, 07:15:24 pm
content: what is the longer term cost of ownership of that rigol? anyone have any guesses?when will the company abandon it? you know it will happen. at what point will it truly be unfixable, even by rigol?what is the warranty period? and even then do you have to spend a lot mailing it out far away or is it locally mailable for in and out of warr service?sure, its a good price and it looks attractive, but my bet is that it will be abandoned by the vendor in a few short years and after that, it will be 100% worthless if it breaks in any serious way. throw the whole thing out and rebuy it, that's the new style ;(so, while its covered by the first warranty period, how much use do you want or plan to get out of it? how many years can you get before you can 'write it off' like a company would?I think people are not looking at the longer term C.O.O.

author: G0HZU
author_rank: Super Contributor
timestamp: March 22, 2014, 08:03:19 pm
content: QuoteI don't think it is that significant an issue. It costs about the same as a laptop and you can guarantee that the laptop will be obsolete in a few short years.If I had to choose between the Rigol and the 2465 I'd take the Rigol in a heartbeat. I do RF design for a living but I still don't want the 400MHz 2465. At my place of work I haven't seen anyone use a 2465 professionally in over 20 years. The demand for these scopes died 20 years ago. I know a lot of hobbyists buy them and love them but it is the equivalent of a sprightly grandad at a disco... he knows a few quick and exclusive moves but at the end of the night nobody (in industry) wants to take him home... If they did then scopes like this would still be mainstream today.QuoteExactlyI agree with sync and MarkL. You 'can' use an analogue scope for this stuff and there's no need to buy anything special. But I can guarantee that if you spent an afternoon with a reasonable DSO the analogue scope would begin to look and feel very dated and limited. Don't spend big money on an analogue scope to find out this lesson. My last two analogue scopes cost £52 and about £30 each.

author: KJDS
author_rank: Super Contributor
timestamp: March 22, 2014, 08:17:19 pm
content: I've had a rummage round my storage lot and found a couple of Kikusui scopesA COS5020, 20 MHz analog two channel, £45 plus £10 shippingA COS5060A 60MHz analog two channel with delayed trigger, £75 +£10 shippingI'll add in a working probe too. I've tested them and they are ok, though I need to clean the switches on them as they are a little intermittent.Message me if you're interested.I don't believe that the high end analog scope is completely dead, I still prefer one when an oscillator is doing odd things, though I also want a decent DSO as well.

author: Bunk
author_rank: Contributor
timestamp: March 22, 2014, 08:32:04 pm
content: Quote from: G0HZU on March 22, 2014, 08:03:19 pm

author: linux-works
author_rank: Super Contributor
timestamp: March 22, 2014, 09:33:47 pm
content: Quotein the industry, is key. again, this discussion is about HOME USERS. therefore, what you said completely does not apply.'industry' can afford new things and can even rent things for spot purposes or short durations. industry can play bookkeeping games and make expensive stuff affordable.I still maintain, for home users, a very good, well engineered, well documented and well supported analog scope is prio #1. digitals will come and go and those are more short-term buys. the tech changes so fast. older used classic analog scopes are what they are and don't need 'firmware updates'. once you buy a good one, you own it for life. if you are going to own analog for life, why not get a classic that has a ton of support, etc?

author: nctnico
author_rank: Super Contributor
timestamp: March 22, 2014, 11:27:17 pm
content: I assume you still drive around in a model T Ford with no airbags, cruise control, ABS, airconditioning, navigation, ESP, windscreen wipers, an electric starter, etc?Buying an old scope is just like buying an old car: you miss out on all the good stuff advances in technology have brought along. Good oscilloscopes are finally affordable for the home user. So why insisting on using old crap?

author: linux-works
author_rank: Super Contributor
timestamp: March 22, 2014, 11:33:21 pm
content: I see it 100% the other way.you can own a used, classic ferrari (maybe it wont have air bags) or a new hyundai.I see the modern lower and middle end digitals as throw-away engineering works. get the firmware good enough to sell enough in 6mos to 2 yrs, then EOL it and start on a new project.if you like that, fine. not everyone wants 'teh new shiney!' and we like our old classic reliable stuff that was done right, rather than done in a hurry.

author: G0HZU
author_rank: Super Contributor
timestamp: March 22, 2014, 11:54:08 pm
content: An analogue scope is a useful thing to have on any test bench but experience and common sense has taught me that you don't need to spend a lot of money to get a perfectly adequate analogue scope. £50 will get something really nice if you are patient,otherwise spend/risk maybe £100.However, even my crusty 8 bit Tek TDS2012 will totally outclass my 465 (or even a 2465) for accuracy when it comes to measuring simple and repetitive waveforms. It will be quicker, easier to use, it offers far more versatility (eg maths routines)it can do a spectrum analyser display and see distortion down to -60dBc at AF.I can ask it for all kinds of automated measurement such as rms voltage, period, frequency, Vpkpk, pulse width etc etc. and it consumes about a tenth of the power of a 2465 and is small, light, very portable and is silent in operation. (no fan noise!)With a modern digital scope you can capture data and post process it and store it on a PC. With a typical analogue scope you canonly look at the screen or take a photo of it.However, my old 465 is great for looking at complex waveforms. eg modulated RF waveforms. The TDS falls over badly here due to annoying alias issues. So the old 465 is safe on my bench for a good while yetHowever, digital scopes are getting better in this respect every year and when I do upgrade the TDS2012 I expect that thecapabilities of the new DSO will mean I use the 465 even less. I would expect that many people will have a similar experience.

author: G0HZU
author_rank: Super Contributor
timestamp: March 23, 2014, 12:01:02 am
content: QuoteIn the case of the classic 2465 I can only offer my own opinion... I last used one nearly 25 years ago at my first job. The headof the department insisted on having the best scope so he made sure he had a brand new 2465. I had an old 465 as did most of thestaff there. When he went on holiday he used to offer me the use of the 2465. I felt blessed...But the first day I used it I quickly put it back on his bench because it had loads of annoying winky LEDs in the front panel user interface and the trace wasn't as sharp as my 465. It was also bigger than the 465 and couldn't fit as neatly on the shelf. The controls were too small and cramped and fiddly and it basically looked plastic and cheap. It took me less than a day to realise that this scope was better off on the boss' bench as a status/trophy scope.None of the stuff I was doing needed the bandwidth. Today, if I need to look at a modulated RF signal at 400MHz or even at several GHz I can mix it down to a low IF and look at it on my little 465.The 2465 would be better at looking at fast risetimes of waveforms and for looking at (obsolete?) stuff like HD video but I can't really think of a practical use that justifies the cost/risk of ownership of an old £££ analogue scope that is well known to be unreliable and has probably already had more bodger/tech fingers inside it than a vintage SW radioIt's a legendary and very capable scope that attracts hobbyists like moths to a flame but I would not want to see one where my 465 is currently located. I guess I'm immune to the hype

author: linux-works
author_rank: Super Contributor
timestamp: March 23, 2014, 12:18:30 am
content: I can't get onboard your comment about 'well known to be unreliable'. that sounds a lot like opinion and not fact based, unless you know of people who have had them break on them numerous times.I'm aware of what goes wrong on these and they are in a league entirely above the chinese rigols. those will have cap failures in 2 years or so, time (my guess, fwiw). the tek's have been running for 20 yrs before needing an overhaul. that speaks well of the tek design and build. there isn't enough longevity data on rigol but by all accounts, its NOT meant to last 5 yrs, even. I'm sure some will, but I'm sure a lot will have failures before then. and when they break, good luck getting them fixed.its cool that you used the tek scopes so many years ago, but because they are old does not make them any less desirable in the used market, for home EE lab guys.as for the user interface, you complain about this and yet you enjoy using digitals of today?? boggle! digitals of today SUCK in user interfaces. they reuse controls over and over, you have to menu thru things to get to what you want and they tend to have less knobs to turn and more overloaded functions on each of the knobs they do have.

author: Nerull
author_rank: Frequent Contributor
timestamp: March 23, 2014, 12:20:58 am
content: Frankly its pretty obvious that you've got a major axe to grind. You throw out conjecture and BS and then accuse other people of stating "opinions and not fact".

author: linux-works
author_rank: Super Contributor
timestamp: March 23, 2014, 12:29:06 am
content: my axe to grind (if you want to call it that, I guess) is from modern product engineering that does a fast 'time to market' and cost reduction and everything else is 2nd. I don't like test equipment to be designed and built that way. its fine for commodity things like mp3 players and home stereos, but does not fly when it comes to test gear that we should own and use for a long period of time.

author: G0HZU
author_rank: Super Contributor
timestamp: March 23, 2014, 12:33:51 am
content: QuoteThe only DSOs I have used are the old Tek TDS2012 series and the big Tek MSO/DSO 4000 because those are the most common scopes at work and I only ever need a basic DSO anyway.We have some huge high cost Tek and Agilent DSOs (with rows of cooling fans down the sides) but these are aimed at different type of user. So I've never tried one and I don't have a clue what model they are.The only scope I've seen at work that is as visually annoying as the 2465 is a 20Gs/s R&S RT1044. It's supposed to be the top model in their range. We have one on loan and the multi-coloured lamps behind the front buttons are incredibly bright. Apparently these are adjustable but it also has a row of distracting onscreen user icons that look like something from a freeware GUI.

author: Nerull
author_rank: Frequent Contributor
timestamp: March 23, 2014, 12:40:30 am
content: Rigols have been out for a while now, well past your two year estimate. Is there any evidence of this "disposable" high failure rate? No one should have any left working, by now!

author: Kilroy
author_rank: Regular Contributor
timestamp: March 23, 2014, 02:57:40 am
content: Quote from: nctnico on March 22, 2014, 03:17:44 pmNo...not impossible.Quote from: sync on March 22, 2014, 03:42:56 pmNo...not necessarily true.The two HP analog storage scopes I use have no trouble displaying accurate, real time low frequency waveforms with sharp, solid traces....and have done it for years and years.

author: EEVblog
author_rank: Unknown
timestamp: March 23, 2014, 03:36:06 am
content: Quote from: linux-works on March 22, 2014, 09:33:47 pmI disagree.A modern deep memory digital scope should be the #1 requirement of any lab, beginner or otherwise, unless you absolutely cannot afford the $300 or so for a modern entry level DSO, in which case a <$100 analog is a good choice.People think that I recommend an old analog scope over a modern digital - no way. A modern digital scope is a far more useful and versatile tool than any analog scope ever made.And as I've mentioned in my often quoted rant video on the top, an old analog is still a better tool than one of those cheap toy handheld or kit DSO's.

author: vk6zgo
author_rank: Super Contributor
timestamp: March 23, 2014, 03:40:30 am
content: Quote from: G0HZU on March 23, 2014, 12:01:02 amWhat's obsolete about HD video?It is the standard for Terrestrial Digital TV-----did you mean analogue TV?Quote from: G0HZU on March 23, 2014, 12:01:02 amI can't actually place the 2465 in terms of time,but I do remember that the last model analogue Tek we had at the TV station (which may have been a bit later generation),kept failing & being fixed under warranty.Tek tried to swap it for some of the (very inferior) early DSOs,but got sent home "with a flea in their ear".Eventually,they came up with one which,although it looked like it was made by Mattel,wasjustcapable of displaying a PAL field which still looked like video,although there was a nice "beat note" against the 4.43 MHz chroma subcarrier.Itwasuseable,however,& it didn't croak all the time like the analogue,so we accepted it.Those of us who tried to use the early DSOs from both Tek & HP for general Electronics maintenance & repair tend to have a rather jaundiced view of DSOs from that experience.

author: EEVblog
author_rank: Unknown
timestamp: March 23, 2014, 03:51:28 am
content: Quote from: vk6zgo on March 23, 2014, 03:40:30 amFor sure. Almost all of them were pretty horrid. It wasn't until the real-time TDS200 series did DSO's get the rep of being actually usable for general use.

author: oldway
author_rank: Super Contributor
timestamp: March 23, 2014, 04:06:44 am
content: Who is clever, has good knowledge of electronics and experience can do a lot of great work with an analog scope.http://www.linear.com/williams.php

author: EEVblog
author_rank: Unknown
timestamp: March 23, 2014, 04:30:26 am
content: Quote from: oldway on March 23, 2014, 04:06:44 amSure, but you can do even more with a digital storage scope.

author: oldway
author_rank: Super Contributor
timestamp: March 23, 2014, 07:57:34 am
content: That's only true if what you are doing requires it.And mostly, that's not the case with hobbyist.

author: EEVblog
author_rank: Unknown
timestamp: March 23, 2014, 08:21:24 am
content: Quote from: oldway on March 23, 2014, 07:57:34 amThe ability to capture and store a waveform is the biggest advance in oscilloscope usability since it's inception. So much so that the pinnacle of analog oscilloscope design was the microchannel plate design (Tek 2467) that allowed the viewing of fast single shot events, something that any modern $300 DSO does with the utmost of ease and to even greater usability (with deep memory). To imply that ability is not generally important is simply crazy.Of course some requirements are entirely met by an analog scope, and a digital is not required. But we are not talking specific usage scenarios here, so the only thing we can talk about is general usefulness. In which case any modern digital oscilloscope offer many very important and useful features simply not afforded by analog scopes. There is no contest.Anyone who could pick only one scope to have in a general purpose lab would be a fool to pick an analog scope.IMO, the storage ability of a modern DSO is even more important to a beginner, because it lets them capture and freeze single shot event and analyse what is happening , without any interpretation or limitations you would have to do with an analog display.

author: tautech
author_rank: Super Contributor
timestamp: March 23, 2014, 08:35:42 am
content: Dave stole a little of my thunder, but I agree.....I've spent so much time repairing the many CRT scopes i have owned, even bought faulty ones to repair and flog off. Telequipment, BWD, HP, Tek and another UK brand I have forgotten.Mostly faults in the HV as most components there are under stress, thermal and electrical, but not confined to HV. Defection amps, linear PSU's SMPS, timebases, crook pots, skeletal presets, popped tants, electrolytic's etc etc.Oh and a Tek TDS210 with a dead LCD backlight inverter, believe it or not, bought from an EE.There is so much more to go wrong with a CRT scope.And when it does, the first thing you will need is another scope!!!!Learn how to use a DSO to best effect and stick with it.All scopes will display spurious waveforms, it is for the operator to interpret that what they see is actually happening. Be confident before you hook up of what you expect to see and if it is not expected, firstly question your setup. Learning how to fully drive a DSO demonstrates your full understanding of the DUT and your instrument.EDITDon't get me wrong, I am thankful for the time spent and consequent knowledge gained while owning CRT scopes, but now I can pursue my projects without the frustration of dead test gear!!!

author: oldway
author_rank: Super Contributor
timestamp: March 23, 2014, 12:12:44 pm
content: QuoteFor sure, you write about something you don't know.Hameg has sold more than 300.000 units of the HM203 model...And most of them still work.Some analog scopes are older than 30 years, have been used for thousands of hours and are still working.If you could have some experience in repair of analog scopes, you would know that most failures have 3 origins:- front end pre-amplifier: you have the same risk on digital scopes.- power supply: you have a higher risk of failure on digital scopes because they use SMPS which is not as reliable as the linear power supplies of most of the analog scopes. (not for the 2445/2465)- HV oscillator and HV multiplier...that do not exist on digital scopes, but it does not fail as often as you seem to think.

author: Bunk
author_rank: Contributor
timestamp: March 23, 2014, 01:14:08 pm
content: Thanks again everyone for their contributions. I think I'm gonna go with the Rigol 1074z as soon as they are back in stock here in the UK. I weighed up 2000 range but they come in above my budget by a fair margin. the way I see it with the trade off of lower BW (not a problem for me) I get the bigger display (than the cheaper still 1052e) with intensity grading and 4 channels. I'm also gonna pick up a simple analog scope to play with and learn with. Maybe a Hameg or older Tek or something similar.As I have already said I used to use the Fluke 123 but that was pretty much in auto mode and I used the multimeter aspects as much as the scope itself. It's a shame its fallen over but I just can't rely on it anymore (freezing, some modes randomly not available etc not to mention the nicad pack wants replacing). I've not drilled right down but I wouldn't be surprised if the Rigol has better spec's than the 123 as the Fluke is well over 10yrs old now.

author: G0HZU
author_rank: Super Contributor
timestamp: March 23, 2014, 02:30:08 pm
content: QuoteYes, sorry for any confusion. I was loosely referring to the various HD video formats of the 70s, 80s and 90s. One of the key selling points of the 2465 (compared to digital scopes of the same era) was that it could display HD video and show any subtle video problems as a change in the 'intensity' of the scope display. It could also trigger and display waveforms at an extremely high rate.

author: nctnico
author_rank: Super Contributor
timestamp: March 23, 2014, 03:03:52 pm
content: Quote from: oldway on March 23, 2014, 12:12:44 pmYou are forgetting about worn switches and potmeters. A major nuisance with any well used analog scope.

author: KJDS
author_rank: Super Contributor
timestamp: March 23, 2014, 05:43:37 pm
content: Quote from: nctnico on March 23, 2014, 03:03:52 pmI find that the biggest issue with scopes is intermittent switches on those that haven't been used much, or at least the switches haven't been used much. Fortunately a quick squirt is all that is required to sort these.

author: sync
author_rank: Frequent Contributor
timestamp: March 23, 2014, 07:35:33 pm
content: I done some probing in my synth (Arp Odessy) for comparison. The DSO is a DS1074Z, the analog is a Tek 2246A. On both the bandwidth was limited to 20MHz. You can see a weakness of the DS1000Z. It's sometimes more like a 7 - 7.5bit scope. So the horizontal traces are thick. On repetitive waveforms the averaging acquisition mode helps here.Here the VCO outputs for sawthooth and square wave. The first DSO picture is from normal acquisition mode, the second from averaging acquisition mode.

author: sync
author_rank: Frequent Contributor
timestamp: March 23, 2014, 07:37:19 pm
content: Here the VCF output from the sawthooth with a bit of resonance.

author: sync
author_rank: Frequent Contributor
timestamp: March 23, 2014, 07:41:39 pm
content: Here examples for control voltages. First is an output of the ADSR evelope generator. Second is a sample-and-hold output from noise, triggered by LFO. It's a analog random generator. Both are too slow for the analog scope.

author: linux-works
author_rank: Super Contributor
timestamp: March 23, 2014, 07:49:07 pm
content: Quote from: KJDS on March 23, 2014, 05:43:37 pmthat's why I suggested the 2400 series scopes. they are relay-driven with the switches and pots on the front panel being ONLY control elements to a cpu and not passing any signal thru them or any current that would cause pot noise or switch arcing. the 2400 has cursors which I won't want to live without (my 2225 has no cursors and I miss them when I switch to that scope).so, while the 2400 may be 'overkill' for some tasks, it has enough features that make it very reliable and usable. it won't be the best for every task, but even though I have both the rigol digital and tek analog here, I'm usually turning the tek on instead of the rigol for most things. I would not get rid of either of them and I do suggest owning both kinds, but I'm not one of those guys who prefers the digital display and 'modern' menu based style over the 'each knob does one thing and does it well' UI style that the analog scopes have.if the 2465 is too much money, there is a lower cost and lower BW version, the 2445 and you still have the same nice UI and relay/control interface.

author: Bunk
author_rank: Contributor
timestamp: March 23, 2014, 09:06:44 pm
content: Thanks sync for posting those examples! Real world stuff like that helps me understand the some of the tech terms I've encountered.

author: Bunk
author_rank: Contributor
timestamp: March 23, 2014, 09:14:45 pm
content: Anyone have any experience of these?http://www.jameco.com/1/1/24635-os-5020-20mhz-2-channel-oscilloscope-test-measurement.htmlThere is one over here for sale for £149 but he'll accept an offer.Pro's - It's a recent model compared to some of the older 'scopes out there ergo it'll have less hours on it, Its got all the gubbins with it including printed manual and delayed sweep lead.Cons's - It's a recent model compared to some of the older 'scopes out there ergo it'll be built cheaply with custom ic's, It's prob pricey for a 60Mhz scope with a fairly basic spec?? I've not found a schematic yet but I've read that Jameco can provide a pdf.Any thoughts? Just throwing it out there as someone mentioned buying a new scope earlier in the discussion.

author: oldway
author_rank: Super Contributor
timestamp: March 23, 2014, 09:20:44 pm
content: Quote from: nctnico on March 23, 2014, 03:03:52 pmWorn switches are not commun....sometime worn rotary switches on 465/475/22xx.Bad contacts on switches are more commun, mainly if the scope has not been used for a long time.It's easy to solve with contact cleaner.There are bad contacts on rotary switches of some scopes as Philips PM326x , (other models of Philips use reed relays).For the potmeters, there are very few worn potmeters because they are not extensively used.http://www.jameco.com/1/1/24635-os-5020-20mhz-2-channel-oscilloscope-test-measurement.htmlLow end analog scope of the same (low) level of quality as Hung Chang...http://www.radiomuseum.org/r/hungchang_oscilloscope_os_620_depos.html

author: MarkL
author_rank: Unknown
timestamp: March 23, 2014, 09:42:18 pm
content: Quote from: sync on March 23, 2014, 07:35:33 pmI notice there's a little non-linearity showing up on the analog traces, circled below, that do not show up on the Rigol. Which is right? Perhaps a mis-adjusted probe? A straight coax connection (no probe) might settle that at least.But this also got me thinking, along with another post in this thread referencing rise times, that in analog scopes there's a lot more to the signal path that has to be just right to keep the signal-to-eyeball fidelity. Everything from the front BNC to the vertical deflection plates has to be perfect.I recently recal'd my 2465, and to tweak the high frequency response there are no less than 7 pots/caps/inductors, one selected value inductor, and two wires you need to squeeze together. They all interact, and in the end it's a compromise on what you'd like your distortions to look like inside a 4% spec. It's very subjective and 4% is very visible. And to be extra annoying, the two main channels were slightly different, so it was also a compromise between all those adjustments *and* the two channels. Neither a Tek 3054 or Agilent X3104 showed any of the distortions I was seeing; it was all inside the 2465.Contrast this to digital scopes, where the signal is gotten into the digital domain as quickly as possible. The physical length of the signal path where distortions could be introduced, I would venture a guess, is about a magnitude less. There's also no shared analog circuitry, delay lines, analog channel switching, etc. which can only detract from signal integrity. And calibration? Reduced to a button in many modern scopes.I'll probably never give up my 2465. It and the other high-end scopes of the day are technological masterpieces, and it's a lesson in engineering design every time I open it up. But it's just not the one who's power button gets pushed when it's time to get work done.Edit: I'll take back that part about digital scopes not doing analog channel switching. Many, but not all, digital scopes will share a common ADC by switching between analog channels. But still, the point is the analog signal path is much shorter in digital scopes.

author: vk6zgo
author_rank: Super Contributor
timestamp: March 23, 2014, 10:20:25 pm
content: Quote from: Bunk on March 23, 2014, 09:14:45 pmDoubtful if it will have custom ICs---these were used by Tek & HP because they could afford it.This probably uses mainly generic components,like the little single channel Jaycar one I have sitting in the shed.The HT supply for the tube died----one transistor in the HV inverter failed.I didn't have the correct part,but I did have one in the same package,removed from a TV set SMPS.Chucked it in,& the thing worked OK for years.Any'scope is better than none,but an old Tek, HP or similar is light years ahead of these beasts.

author: sync
author_rank: Frequent Contributor
timestamp: March 23, 2014, 10:34:52 pm
content: Quote from: MarkL on March 23, 2014, 09:42:18 pmI noticed it too. I had adjusted the probe compensation directly before the measurements. I test the probe again (1st picture). It's a Tek P6109. There is a little bit overshot. But there is also a dip after the edge. The adjustment is a compromise. For comparison I use a DIY Z0 probe (2nd picture). There is a tiny overshoot.The overshoots of the synth measurements are higher. I don't know the cause. Maybe bad ground connection. I connected the ground clip to the chassis.

author: Bunk
author_rank: Contributor
timestamp: March 23, 2014, 11:45:56 pm
content: Well I I've taken the plunge. I've got a Tek 468 on the way. Overkill I know but hey ho. It wasn't that expensive.

author: linux-works
author_rank: Super Contributor
timestamp: March 23, 2014, 11:51:22 pm
content: the 400 series teks had a really classic and easily recognizable interface. if yours is in good condition, you should be happy with it.you're still going to get a cheapie digital, though, right?

author: c4757p
author_rank: Super Contributor
timestamp: March 23, 2014, 11:51:40 pm
content: sync, that distortion on your analog scope - it does look like poor compensation. Might not be the probe though. I'm not familiar with the 2246A, but it probably has a few compensation adjustments internally in the various amplifier circuits. Maybe it just needs a cal?

author: Bunk
author_rank: Contributor
timestamp: March 24, 2014, 12:01:19 am
content: Quote from: linux-works on March 23, 2014, 11:51:22 pmI'll see. No doubt it (the digital) will come in handy (possibly more than I realise now) so yeah, more than likely the 1074z wen the time comes.I want to learn properly with the tek and get a good grounding (pun alert). Th listing says its fully working, there are waveforms displayed, its got probes with it but it needs calibration according to the seller. The waveforms on the images look ok so who knows. i decided to stop messing about and take a punt. Here goes….

author: sync
author_rank: Frequent Contributor
timestamp: March 24, 2014, 12:52:38 am
content: Quote from: c4757p on March 23, 2014, 11:51:40 pmI just made a test with a function gen with the same scope settings as in the distorted synth measurements, but using coax + termination. The linearity error is about 0.1 - 0.2mm using a 6 div p-p sawthooth signal. Very hard to see. No over- or undershoot. At the edges of the screen the scope has a little geometry error which can't fixed by adjustment. I tried it. But this error is within spec.

author: PaulAm
author_rank: Frequent Contributor
timestamp: March 24, 2014, 01:22:07 am
content: The 468 is essentially a 465 100 MHz scope with a DSO option added. The digital side is good for 10 MHz and, if I remember correctly, has around 512 sample points. It does give you cursors for time and voltage measurement while in DSO mode.The CPU chip in the digital section is the single largest IC I have ever seen, anywhere.There are two volumes for the manual for the scope, both are available free online. Be sure to get both of them.

author: Bunk
author_rank: Contributor
timestamp: March 24, 2014, 06:17:59 pm
content: Quote from: PaulAm on March 24, 2014, 01:22:07 amThanks Paul. I downloaded the user and service manuals last night. The service manual is a 65Mb file!

author: David Hess
author_rank: Super Contributor
timestamp: March 28, 2014, 06:28:00 pm
content: Quote from: MarkL on March 23, 2014, 09:42:18 pmI noticed the same thing.It is too slow to be a transient response problem but it could be the probe compensation, attenuator compensation, or compensation of the input buffer.QuoteI have occasionally seen similar problems with modern DSOs where the transient response of the signal was obviously wrong and uncorrectable so this is hardly a unique issue with analog oscilloscopes.QuoteThe DSO problems I have seen were on the digital side. In one case it was aliasing caused by the interleaving of the digitizer which showed up after sin(x)/x reconstruction. Agilent has a good application note which mentions this. In another expensive DSO, it was the DSP bandwidth limiting which caused unacceptable transient response.QuoteThe trend has been to go to one unshared digitizer per channel but at the highest sampling rates interleaving is needed. Even the venerable Tektronix 2232 uses one digitizer per channel and that is the second to the oldest general purpose DSO that I would consider worth using.

author: David Hess
author_rank: Super Contributor
timestamp: March 29, 2014, 04:10:22 pm
content: Quote from: PaulAm on March 24, 2014, 01:22:07 amI finally had to look at the details of the 468 design.The digital storage bandwidth is limited to roughly 10 MHz by the analog to digital converter which was intended for video applications. Later Tektronix DSOs include a sample and hold to get the full oscilloscope bandwidth. The design looks very much like it is the predecessor to the Tektronix 2230.QuoteThe flash analog to digital converter is uses was made by TRW and sure is big. More than half of the pins on the 64 pin DIP package are not connected.

author: vk6zgo
author_rank: Super Contributor
timestamp: March 29, 2014, 04:30:44 pm
content: Quote from: EEVblog on March 23, 2014, 08:21:24 amI can count on the fingers of one hand,the number of times I've really needed a storage function.Maintenance & repair of equipment isn't really a " specific usage scenario"----it is more like mainstream!EEs definitely have different requirements than people repairing stuff,so DSOs are a boon ,as they can characterise the performance of their projects & save the displays to a PC.People trying to fix something usually don't need to do this,---they just need to repair the faulty thing.

author: David Hess
author_rank: Super Contributor
timestamp: March 29, 2014, 06:29:14 pm
content: For general purpose troubleshooting I do prefer DSOs but I have analog oscilloscopes to fall back on when they will perform better and the applications that absolutely require the features of a digital storage oscilloscope are in the minority. My go-to oscilloscope is a Tektronix 2230 which is both.Digital storage oscilloscope advantages include:Automatic measurements - although some analog oscilloscopes feature automatic measurements in one form or another.Pretrigger record - analog random sampling oscilloscopes have this in a very limited and specialized form.Variable or infinite persistence - analog storage oscilloscopes have this but I would not recommend one.Analog oscilloscope advantages include:Lower perceived noise level - quantization noise can completely hide low level signal details and higher resolution DSOs are expensive. This is a solvable problem but most DSOs get it wrong.Very high update rates - even DSOs with high waveform acquisition rates tend to have less than stellar display update rates.Invariably the one place where I find DSOs invaluable is low repetition rate signals or when I want to store or compare waveforms.

author: Vgkid
author_rank: Super Contributor
timestamp: March 29, 2014, 07:06:45 pm
content: @ Sync : How do you like your 2246, I own one as well.My only complaint on it is if Ch3/4 had more V/div settings.

author: David Hess
author_rank: Super Contributor
timestamp: March 29, 2014, 07:19:24 pm
content: Think of channels 3 and 4 on the 2246 as external trigger inputs with improved trigger view compared to the 465 series. They have two attenuator settings which are appropriate for logic and control signals, have independent position controls, and seamlessly operate in ALT or CHOP mode with channels 1 and 2.

author: linux-works
author_rank: Super Contributor
timestamp: March 29, 2014, 08:32:51 pm
content: same deal with the 2465 series. it does bug me that they are full analog channels but have only 2 atten settings.

author: grumpydoc
author_rank: Super Contributor
timestamp: March 29, 2014, 09:56:35 pm
content: QuoteIt's odd that Tek never did the "logical" thing of building the series with a full 4 channel variant.

author: linux-works
author_rank: Super Contributor
timestamp: March 29, 2014, 11:31:10 pm
content: with the 246x series, at least, the front panel is not 'real', its just control. all signals pass thru relays and boards; and so the front atten knobs could have doubled up. or at least have a 4 way switch for atten for ch 3,4.worst case, you can always atten outside the scope, but you lose the nice direct reading legends.

author: nctnico
author_rank: Super Contributor
timestamp: March 30, 2014, 02:20:07 am
content: A 4 channel scope with 2 half-baked channels is just useless. Maybe nice as trigger inputs with a visual check. I had such a scope and I have learned the hard way to never ever buy a 4 channel scope which doesn't have 4 full attenuators again.

author: David Hess
author_rank: Super Contributor
timestamp: March 30, 2014, 03:06:58 am
content: Quote from: linux-works on March 29, 2014, 11:31:10 pmThe 2246 series is the same way. Some of the late 22xx series are at least partially designed like this but documentation is thin on them. The other 22xx series oscilloscopes which include readouts work more like the 7000 series with a parallel set of readout switches on the cams.The 2246 and 2465 series are pretty crowded both on the front panel and inside so I am not sure a full set of attenuators would have fit anyway. Having an improved trigger view was basically free.

author: Vgkid
author_rank: Super Contributor
timestamp: March 30, 2014, 03:17:35 am
content: I will agree that the ch 3/4 have a use for digital.For the 2246 owners, do your units have a fwn in them?

author: edavid
author_rank: Super Contributor
timestamp: March 30, 2014, 03:18:46 am
content: Quote from: nctnico on March 30, 2014, 02:20:07 amWell, I disagree. I find the extra 2 channels on the 2465 very handy. Usually when I'm looking at 4 signals, 1 or 2 of them are logic anyway.

author: David Hess
author_rank: Super Contributor
timestamp: March 30, 2014, 03:38:15 am
content: I agree. The deflection factors work out to 1 volt/division and 5 volts/division with a x10 probe which is fine for logic and control signals.

author: c4757p
author_rank: Super Contributor
timestamp: March 30, 2014, 03:57:05 am
content: The limited attenuators on Ch 3 and 4 only bothered me on my 2445A for the sixty seconds it took me to complain about them, when I first got it. I don't even think about it any more, 1V and 5V/div are quite good for anything I've ever had to put on them.

author: David Hess
author_rank: Super Contributor
timestamp: March 30, 2014, 06:16:33 am
content: I am usually either using them as external trigger inputs, a much under appreciated feature, with or without displaying them or to watch logic level signals in a mixed signal design.If I need 4 full channels then I either have to break out one of my 7000 series oscilloscopes or use both of my 2230s. A couple years ago when I went hunting for a 4 channel DSO, I concluded that buying and refurbishing a pair of 2230s was the most cost effective option. The only thing which I find lacking about the 2230 as a DSO is its lack of variable persistence and bandwidth limiting.

author: MarkL
author_rank: Unknown
timestamp: March 30, 2014, 06:56:23 pm
content: Quote from: David Hess on March 28, 2014, 06:28:00 pmI have seen that too, and I'd be the last to claim DSOs don't have some of the same problems. Plus their own unique problems, like interpolation, as you mentioned.I'm only saying in an analog scope there's more of an opportunity for distortions to be introduced. At a minimum, there's the amplifiers that drive the plates in the CRT, the CRT itself, analog switching between channels, and driving the delay line. There's simply more things that need to be matched perfectly and/or tweaked that don't exist in a DSO.

author: sync
author_rank: Frequent Contributor
timestamp: April 01, 2014, 08:58:02 pm
content: Quote from: Vgkid on March 29, 2014, 07:06:45 pmI love it. I was searching for a Tek with cursors and readout for a lot of months. The 2465 (2445) are too expensive and have their problems (lost of calibration, bad hybrids). Then I found the 2246A on ebay. I like that the signal path is separated from the front panel controls. No problems with bad switches or pots. I really like the automated measuring. It has hybrids too. But not as many and sophisticated as the 2465. What I don't like is the noisy fan.For me it's a two channel scope with two additional limited channels.

author: TVman
author_rank: Frequent Contributor
timestamp: April 01, 2014, 09:22:22 pm
content: Spend your money on analogue!

author: Vgkid
author_rank: Super Contributor
timestamp: April 01, 2014, 10:51:51 pm
content: Quote from: sync on April 01, 2014, 08:58:02 pmI dont believe mine has a fan, havent used it in 6 months.

author: David Hess
author_rank: Super Contributor
timestamp: April 01, 2014, 11:36:21 pm
content: Quote from: Vgkid on April 01, 2014, 10:51:51 pmAs far as I now all of the 2246A series include fans but usually they are quiet enough to to be unnoticeable.

author: TVman
author_rank: Frequent Contributor
timestamp: April 02, 2014, 12:08:53 am
content: Look on ebay....http://www.ebay.com/If you can't find one:https://www.eevblog.com/forum/blog/eevblog-498-how-to-get-a-$50-oscilloscope-on-ebay/GD luck!

author: Vgkid
author_rank: Super Contributor
timestamp: April 02, 2014, 12:25:15 am
content: Quote from: David Hess on April 01, 2014, 11:36:21 pmThat makes sense, I forgot that my fan would rattling unfrequently.

author: edavid
author_rank: Super Contributor
timestamp: April 02, 2014, 01:26:32 am
content: Quote from: David Hess on April 01, 2014, 11:36:21 pmOr sometimes they are completely quiet because they've seized up, or the driver is broken.

author: Seg
author_rank: Regular Contributor
timestamp: April 02, 2014, 03:30:17 am
content: Speaking as an owner of a LeCroy 9400A, it's cool if you can get one for $50-ish, any more than that and you're better off with a hacked Rigol DS1052E. The Rigol will out-perform the 9400A in every practical way. The 9400A is a HUGE, slow, hot, power sucking monster.Only plus is maybe the vector(!) CRT on the 9400A is a bit sharper than the Rigol's chunky 320x240 LCD...

author: David Hess
author_rank: Super Contributor
timestamp: April 02, 2014, 10:23:14 pm
content: Quote from: Seg on April 02, 2014, 03:30:17 amI would never recommend a LeCroy 9400A simply because of the lack of a peak detection mode.QuoteI always thought it somewhat odd that modern DSOs are only now catching up to early vector CRT DSOs as far as screen resolution. 1024x512 or higher was routine on 5 inch vector CRTs which is considerably higher than the 72 DPI on standard LCD screens. It makes sense from an economics perspective though since test instruments are largely stuck with display technology intended for monitors which are now largely stuck with display technology intended for entertainment displays. "Retina" class displays until recently have been limited to special applications that can afford the extra expense.Antialiasing and using subpixels in a low resolution LCD displays should help a lot with that but I have not seen it done in inexpensive instruments.

author: acbern
author_rank: Frequent Contributor
timestamp: April 02, 2014, 10:41:15 pm
content: @bunkin germany 2465b (400Mhz) do sell regularly at about 500 to 550 pounds st., I find this reasonably priced. the other interesting one I would recommend, suitable for all kinds of use, is the 7000 series from tektronix. the 7104 with a 7a29 plug in goes up to 1ghz, amazing. now of course you dont need this for audio and the like, but other plug ins such as differential do help a lot there sometimes. and the interesting thing is, they sell at pretty low prices sometimes in the us bay.

author: guido
author_rank: Regular Contributor
timestamp: April 02, 2014, 11:18:15 pm
content: I'm currently working on a 2465. It needs some repairs and i did a recap. Didn't pay much for it (80 euro including one brand new matching 400MHz probe). The switches panel was in a bad state, but i bought a working one from Israel. They sure do take apart a lot of stuff there, sometimes stuff that met a sledge hammer... But this panel was fine. Also recapping my 2430A while i'm at it, and a fresh battery.So old scopes do need some work now and then. Got 7000 mainframes too, same thing. But parts are usually available.You can load those with nice goodies like SA's and differential amps. But they take a lot of bench space, so i don't use them as 'regular' scope.As for my main scope, it's analogue. Digital controlled though, modern. It's an Iwatsu 100MHz (SS-7810). Love it. Got the schematics and made a calibration pod. It was also sold as LeCroy. I can recommend it. I don't have a modern digital one, don't miss it. If i want to decode serial busses, i use a logic analyser. Measure slow changing signals (let's say DC over time), a meter with PC connection does the job.If i needed a DSO, i would have bought one by now. Maybe if i didn't have the 2430A. Don't buy old DSO's, unless it's becomes a hobby

author: David Hess
author_rank: Super Contributor
timestamp: April 03, 2014, 12:10:54 am
content: Quote from: guido on April 02, 2014, 11:18:15 pmI would not buy any DSO which lacks peak detection but that excludes some recent Rigol models as well. Old notable DSO's which include it are the 2230 and 2430 series although the follow-on TDS units to the 2430 series with CCD based digitizers lack it.

author: KJDS
author_rank: Super Contributor
timestamp: April 03, 2014, 09:38:20 am
content: Quote from: acbern on April 02, 2014, 10:41:15 pmHow heavy is a 7104. Someone has offered me one but if I can't pick it up then it will be difficult.

author: David Hess
author_rank: Super Contributor
timestamp: April 03, 2014, 09:48:14 am
content: Quote from: KJDS on April 03, 2014, 09:38:20 amThe mainframe weighs 44 pounds according to the manual but a full set of 4 plug-ins will add about another 10 pounds.

author: eurofox
author_rank: Unknown
timestamp: April 03, 2014, 10:16:02 am
content: I have a Tek 5000 series with most of plugins (13 units), I bought it for the differential 10µV but I could finally find the Tek amplifier to connect to a normal scope with similar features.Only for local pick-up for a symbolic price and I add free a frame 5000 with memory but the CRT is dead.eurofox

author: Neganur
author_rank: Unknown
timestamp: April 03, 2014, 01:09:13 pm
content: Quote from: KJDS on April 03, 2014, 09:38:20 amThe one that I'm selling weighs 22.2 kg without plugins. The custom-made box it goes in is 6 kg.

author: KJDS
author_rank: Super Contributor
timestamp: April 03, 2014, 01:33:52 pm
content: Thanks for the replies, that's not too heavy so i'll buy it.I've also managed to buy a Tek 2465B today so it's been a good day for buying scopes.

author: N2IXK
author_rank: Frequent Contributor
timestamp: April 03, 2014, 02:12:41 pm
content: The 7104 is a great scope if you truly need the 1 GHz bandwidth and high writing rate. A true wonder of engineering, and would be a terrific subject for a teardown video (lots of geek porn inside).But the Achilles heel is the microchannel plate (MCP) tube. VERY susceptible to phosphor burn, and finding one that still has even brightness across the entire screen is becoming difficult. The readout areas in particular seem to dim out noticeably. The only source for replacement is another 7104, as this tube was unique to it.If you want a 4-slot 7000 series mainframe, the 500 MHz 7904/7904A might be a better candidate as far as spare parts availabliity, as there was a lot more parts commonality with other models.

author: edavid
author_rank: Super Contributor
timestamp: April 03, 2014, 03:24:15 pm
content: Quote from: N2IXK on April 03, 2014, 02:12:41 pmThe trick is to buy a broken mainframe that's been sitting around unfixed for many years

author: linux-works
author_rank: Super Contributor
timestamp: April 03, 2014, 03:47:24 pm
content: I was very close to buying a used 7104. I posted a whole thread on it. the local store wanted $500 for the scope and 4 plugins (and manual AND cart), but they were 200mhz plugins, not the nice 1ghz ones. scope was in decent shape but the size was a showstopper for me and the display is a 'time bomb' that will stop working more and more as you use it. I didn't like worrying about USING the thing; reminded me too much of LP records in that the act of using them is destructive.I also really enjoy having cursors on the scope screen and you really should avoid any writing to the screen with a 'bright eye' tube.

author: David Hess
author_rank: Super Contributor
timestamp: April 03, 2014, 04:59:18 pm
content: Quote from: N2IXK on April 03, 2014, 02:12:41 pmNot only is the MCP CRT very susceptible to phosphor burn, but every cell in the micro channel plate itself has a limited operating lifetime and they continuously degrade as they are used. There are a finite number of electronics available from each cell.Quote11 years separate the 7904 from the 7904A which replaced it and they share very little in common. The 7904, 7844, 7834, and 7854 make one self similar group while the 7904A, 7934, and 7104 make another later group.

author: guido
author_rank: Regular Contributor
timestamp: April 03, 2014, 07:56:20 pm
content: Quote from: eurofox on April 03, 2014, 10:16:02 amI'll bite if you have a 5CT1N plugin

author: acbern
author_rank: Frequent Contributor
timestamp: April 03, 2014, 08:41:42 pm
content: I own a 7104 since more than 5 years now and i cannot complain. clearly, this was well used by the owners before me, but the screen is still bright (much brighter than I need), and I am sure, if I do not abuse it but use it in a normal way, it will work for another 5 to 10 years (at least as far as the crt is concerned). also, if set a little brighter, it switches off automatically after a while. so not a high risk there to abuse its screen when working with normal care. what I am more concerned, frankly, are the el. caps.given the price you can get those, they are a bargain. and I do not share the concerns mentioned here.

author: eurofox
author_rank: Unknown
timestamp: April 04, 2014, 09:38:46 am
content: Quote from: guido on April 03, 2014, 07:56:20 pmNot this one, there are better tools now and not expensiveCheck the pictures for plugins + the modules in the frame not in the picture.