Tektronix 2335 - Full function test and value - Page 1
Forum section: electronics / testgear

author: M15H
author_rank: Newbie
timestamp: January 28, 2016, 03:07:57 am
content: Hi,I have an opportunity to purchase a Tektronix 2335 for $250. The owner is not versed in the usage and has only turned it on to test it. Other than simply using the reference functions to test it what should I do to fully put the unit through it's rigors to be sure that it is fully functioning.The cheapest one I see on ebay is ~$300. Should it be functioning properly is it worth spending $250 on an analog scope vs some of the cheaper $300+ digital scope? I like having 100 MHz available but I doubt I would be exceeding 50 MHz usage and I can see the benefits of digital signal output.Thanks for your input.

author: Muxr
author_rank: Super Contributor
timestamp: January 28, 2016, 03:25:46 am
content: The problem with old analog scopes is you never know how long it's going to last. If it's your only scope it might be quite difficult to troubleshoot and repair it if you don't have another scope. Furthermore 2335 has some proprietary ICs which can be unobtanium. If you're going to go analog vintage route, then might as well get a 4xx series scope.The other thing is, today's entry level digital scopes have single shot digital storage capability. Which makes them far more useful. That coupled with reliability, really makes a new or a recent digital scope a much better proposition.

author: SAGOLSEN
author_rank: Contributor
timestamp: January 28, 2016, 05:26:27 am
content: I have to agree with Muxr. It's not worth it. There must be a reason people pay >$300 for an older CRO but I'm not hip to those niche needs. It's too bad the DSOs look like lollipop wrappers but what are you going to do.For some people a few hundred dollars is nothing for a useful tool and if they come across the tool they want, then paying $200 or $300 is no problem for them, I mean what's $100 extra when it's a tool you need in good condition from a good seller?But that's not what you're asking, you're asking about market prices or "going rates" for these scopes. For me, looking over this seller's wares gave me some perspective on what "probably working" scopes are worth. This is the Tek store for shorewa8. Beware the word "calibrated" but I still think he's one of the better sellers. 100 percent ratings mean nothing to me. Well almost nothing.http://stores.ebay.com/Tektronix-Oscilloscope?_trksid=p2047675.l2563As for people who don't know anything about what they're selling, keep in mind that one of the reasons you have this opportunity is that no one else has bought the item. This could be because you're extraordinarily lucky. Or it could mean bad news.Lastly, there are 1001 alternatives to the 2335 that will fit your needs, whatever your needs are.-Mike

author: Muxr
author_rank: Super Contributor
timestamp: January 28, 2016, 05:52:40 am
content: People buy old analog scopes for novelty, nostalgia, familiarity, or just for the controls. It's partly the reason why their prices are a bit inflated. Analog scopes, the good ones at least were designed by engineers and techs who used them on a daily basis, which I doubt can be said for many scopes now days.Just looking at my Rigol DS2072A. The biggest knob, the navigation knob on this scope I rarely ever use, yet the smallest encoder that flexes under pressure, the intensity knob is overloaded with secondary functions.There is also the tactile feedback of Analog scopes that's very seductive, the clicking of knobs and buttons, with instant feedback from the screen, with no lag. New scopes are sterile by comparison.But when it comes to capability, the old CROs can't hold a candle to even the entry level scopes of today. The ability to capture single shot events is probably the biggest advancement, ability to display measurements, advanced triggers, FFT, bus decoding.. the list goes on.

author: M15H
author_rank: Newbie
timestamp: January 28, 2016, 06:13:03 am
content: Thank you both for your honest opinions. I initially thought that it would be a good deal but after doing the research I started to feel like a MFG warranty would be worth a hell of a lot more than the $100 I would save over a new unit.I wasn't even thinking about the additional functionality I would gain from a digital scope. I have an EE degree but have been toiling away for almost the past decade in an unrelated field. The 2335 is very similar to what I used in college, I don't remember model numbers but our labs had Tektronix scopes.Now I just need to figure out which digital scope to buy. There seem to be plenty of threads on that and even more opinions.Thanks,Jason.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: January 28, 2016, 06:39:01 am
content: Quote from: M15H on January 28, 2016, 03:07:57 amDon't do it, just don't. It's a waste of money. As the other posters said, it's really a waste of money.Quote from: Muxr on January 28, 2016, 05:52:40 amThe main reason why analog scopes go for inflated prices is mainly because the myth that to get into electronics one should always start with an analog scope is still going strong, although that hasn't been true for aeons. Even Dave has stated long ago that his old advice to get an analog scope as starter scope is no longer valid.There also are lots of people who are willing to pay almost anything which is labelled 'Tektronix' which also contributes to the excessive prices. Just look at for how much many old Tek DSOs scopes go for.The other factor is that analog scopes are still highly valued in certain sectors of audiophiles because they believe that only an analog instrument should be used to repair their analog HiFi equipment. This is the same audiophiles sector btw that buys oxygen-free cross-polarized and molecularly degaussed speaker cables for $200 a meter, or spends a $1000 on a 3ft high end HDMI cable to improve image and sound qualityThis probably explains why they are often called 'audiophools' although for a clever businessman they can be a great marketQuoteI can see that this is probably true for scopes from the cheap Chinese B-brands (I doubt Siglent has ever used their SDS2000 themselves, otherwise they could have found most of its bugs instead of waiting for users to report them; instead, Siglent uses LeCroy scopes) but the big brand scopes are most certainly still designed by engineers who use them and similar scope on a daily basis.QuoteFunny you say that, as 'sterile' and 'bland' are exactly the feelings I have when I sit in front of an analog scope these days. It's a bit like using a light bulb to check voltages instead of a DMMCan't say that the tactile feedback is much different to a decent digital scope, and the lack of unreliable mechanical switches for many functions is actually a plus in my book.

author: Muxr
author_rank: Super Contributor
timestamp: January 28, 2016, 06:52:40 am
content: No problem. Just to give you a few pointers and some usual suspects. In your price range for a decent entry level scope your choices boil down to these manufacturers from China: Rigol, Siglent, Owon, Gw-Instek and Hantek. The entry level scopes from LeCroy, Agilent/Keysight and Tek are just rebranded scopes from one of the Chinese companies I mentioned (with a hefty markup).Tequipment is a major distributor in the US and they offer discounts for EEVblog members, I believe that's still in effect, so take advantage of that if you can. Once you decide on the scope and you are ready to get it, post in this thread and request a discount code:https://www.eevblog.com/forum/testgear/eevblog-members-discount-at-tequipment/msg852408/#msg852408someone will respond and send you one.Take a look at the Rigol DS1054Z. It's the most popular entry level scope in the past year or so and it's sort of a benchmark of what you can get for less than $400. It's a 4ch, 50Mhz scope, with 1Gs/s. A well documented and easy hack exists that unlocks all the options including the bump to 100Mhz on this scope, so if you get one, hacking it is a no brainer.All these scopes have their quirks and minor annoyance type issue. That just comes with the territory. Their hardware is pretty good, but the software can be buggy or poorly implemented. But do also take a look at other brands and compare. Siglent has the 1000x line. Recent gw-instek scopes seem to have a leg up in FFT capability (based on EEVBlogs latest comparison). And Owon can have some bargains as well.

author: Muxr
author_rank: Super Contributor
timestamp: January 28, 2016, 07:15:46 am
content: Quote from: Wuerstchenhund on January 28, 2016, 06:39:01 amThat's true as well, haven't thought of that one.Quote from: Wuerstchenhund on January 28, 2016, 06:39:01 amThat statement was a bit of an exaggeration on my part, but if you think about it, how many UI programmers do really use scopes on a day to day basis. They don't need to use them to implement the UI. They type on a keyboard and use the mouse to implement the UI.I mean they might be enthusiastic about scopes and they might even use them, or they are just very good designers who do the proper research or go back in history of their own product portfolio and draw inspiration from earlier designs. But my point is, they don't use the scopes to write software. Whereas the guys who designed those analog scopes probably used an analog scope on a daily basis in order to prototype or test their designs.However you're right, there is a world of difference in UI implementation between scopes coming from China and some of the mid tier plus scopes from the west.Quote from: Wuerstchenhund on January 28, 2016, 06:39:01 amThere is definitely something special to tactile feedback in an analog scope, when you reach a limit the knob doesn't just spin endlessly, you hit a stop and you know you did. The software driven rotary encoders often have no predictability, you can't build muscle memory from them like you can on the old scopes with clear notches and stops where the distance turned always consistently results in the same setting. If you ever watch an old tech use his analog scope for a minute you can tell he's operating it from muscle memory, he doesn't even have to look at the screen to know which time division he's on. Same is true for mechanical buttons and toggles. And while you're right about reliability, there is definitely a difference. That's what I mean by tactile feedback.

author: bazsa56
author_rank: Contributor
timestamp: January 28, 2016, 08:04:48 am
content: 250$ is way overpriced. You could get get a brand new Rigol DSO for not much more.If you really spend some time looking you could get something similar like that TEK for less then 100$.I scored a fully functional 2213A for 50+shipping last week. Arrived this Monday and am very happy with it. Needs a bit of cleaning but otherwise works great.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: January 28, 2016, 03:26:00 pm
content: Quote from: Muxr on January 28, 2016, 07:15:46 amAt least for the big brands that isn't how this is done. Yes, the basic UI is developed on a standard PC but then the UI is put on the actual scope hardware which then goes through various functional and usability tests with experienced engineers and UX/HF experts. Flaws (not just software bugs, but also functional and ergonomic/UX issues) are recorded and subsequently fixed/changed, tested again and so on. Before a scope comes to market a lot of people will have used it, and amongst them are many experienced engineers who use scopes on a daily basis. There really goes a lot into the UX design of big brand scopes (although not necessarily in the low end models, which are often bought in from a Chinese B-brand).Having said that, having a just few software developers sitting on their PCs might very well be how the B-brands do their firmware development. It would also explain the sometimes awkward UI design choices and the generally high number of bugs. Proper UI development costs money, and considering the low prices the B-brands are asking for their kit I doubt they have the budget for that.QuoteA lot of the software development for a modern scope actually happens on the scope, especially when the UI is concerned. A desktop PC or laptop is good enough for a lot of steps but at some point the software has to go on the scope, usually with a debugging software running on a connected PC or on the scope itself (usually on a 2nd monitor).I understand what you're saying, and I agree that there are many scopes (especially at the entry level) which show that not much engineering 'love' went into them, but that isn't the norm. You simply can't come up with an intuitive and easy to use scope user interface like MAUI or even the one on Keysight's scopes without 'scope-seasoned' engineers involved, at pretty much all stages of development.Also, most big brands "eat their own dog food", i.e. they use their own products in-house. LeCroy's labs are full of LeCroy scopes, Keysight's labs are full of Keysight/Agilent/HP kit, and R&S uses R&S kit to develop new R&S products. Which is not much different from your example of an analog scope designer, who, although using some analog scope to develop a new analog scope, will also have used a previous model (i.e. the designer of the Tek 2335 will most certainly not have used a 2335 to develop the 2335 but some previous model).QuoteYou're right of course saying that encoders lack the mechanical stop, but I can't really say the encoders on a decent(!), working scope are unpredictable (but how much depends a lot on the software processing encoder input). Plus they don't suffer from the same ailments that the mechanical parts in analog scopes often suffer from, although encoders do fail occasionally (but are generally easy to replace).QuoteI'm not sure that's really 'muscle memory', back in the old days it was merely a thing of twiddling the knob until the waveform on the screen turned out the way you want it. I've grown up with analog scopes (digital scopes were in their infancies back then), and despite using them extensively I certainly couldn't blindly select a specific time base setting (although I might have gotten close by feeling), and I can't remember any other engineer who could. If the problem required for a specific timebase setting then looking at the knob was pretty much inevitable.The other thing is that even if you did remember the settings, an encoder isn't stopping you to do the same on a DSO (just turn it in the opposite direction often enough to make sure you reached the limit, then dial forward the required number of steps). But as using a scope means looking at the screen, with a DSO I find it easier to just look at the corner which shows the relevant parameter when making a settings change.