Oscilloscope Recommendations - Affordable yet repairable? - Page 1
Forum section: electronics / testgear

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 26, 2021, 03:38:43 pm
content: Hello all,I'm looking for a replacement oscilloscope since I had to flog my last one. It was an old cost-cut version of a Telequipment but the documentation and the boards were completely different so I was out without a paddle regards repair and maintenance.So I'm looking for something better documented and more open to repairability, but in an affordable range. I'm not looking for all bells and whistles, something with your standard controls would suffice for my purposes.Any informed recommendations would be greatly appreciated. Thanks.

author: Fungus
author_rank: Super Contributor
timestamp: September 26, 2021, 03:42:27 pm
content: Just buy one that's reliable - no repairs needed!

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 26, 2021, 04:09:27 pm
content: But that's not specifically what I'm looking for in this post.

author: Fungus
author_rank: Super Contributor
timestamp: September 26, 2021, 04:20:14 pm
content: Quote from: ChrisThePackRat on September 26, 2021, 04:09:27 pmOK, but what does "affordable" mean in that post?The Tektronix TAS 485 is maybe the most repairable old 'scope but a decent one will cost you as much as a brand new DSO.Quote from: ChrisThePackRat on September 26, 2021, 04:09:27 pmBasic stuff like number of channels and bandwidth would be good to know as well...

author: nctnico
author_rank: Super Contributor
timestamp: September 26, 2021, 04:36:41 pm
content: Quote from: Fungus on September 26, 2021, 04:20:14 pmAnd a budget! But then again, spending over 30 euro/dollar/pounds on an analog scope is a waste of money. Aliexpress is filled with small DSOs that cost very little and do a much better job compared to any old analog clunker scope.

author: Fungus
author_rank: Super Contributor
timestamp: September 26, 2021, 05:08:11 pm
content: Quote from: nctnico on September 26, 2021, 04:36:41 pmYep. Those things are old. We're at the point where no amount of "repairablilty" is going to save any money in the long term.Another thing is whether you're buying one just because you like the green glow, the clicky switches, the heat they give off, reading the service manuals, opening them up to poke around inside, etc. In that case just get an old Tektronix and ignore the prices.

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 26, 2021, 08:03:09 pm
content: Sorry, affordable would be ~£300 or under.Minimum bandwidth of 20MHz and two channels unless the budget affords for more.I understand the idea with getting something considered more reliable, better economy, but even reliable brands break.I just don't want to go through the whole "just buy a new one" malarkey.

author: nctnico
author_rank: Super Contributor
timestamp: September 26, 2021, 08:46:33 pm
content: Quote from: ChrisThePackRat on September 26, 2021, 08:03:09 pmAnd yet that is the most sensible thing to do. Spending £300 on an analog scope is insane if you just want to have an oscilloscope for making measurements. No offense intended but your question is like ' I'm looking for a model-T Ford to drive 50 miles to work every day'.Analog scopes went obsolete decades ago so everything on the market is more or less junk or some kind of restauration / museum piece. Even the early DSOs are not worth buying these days.

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 26, 2021, 08:53:51 pm
content: I do want to buy a replacement for my other unrepairable one.I'm not a purist for vintage equipment or anything. I'll buy modern and new if I can, I just want something that's also repairable.Surely just because something is brand new doesn't mean it can't be repaired if it breaks.By avoiding the "just buy a new one" malarkey, I'm talking about in the event that the scope that I buy breaks. I prefer to be able to fix it.

author: tautech
author_rank: Super Contributor
timestamp: September 26, 2021, 08:59:28 pm
content: Quote from: ChrisThePackRat on September 26, 2021, 08:53:51 pmAs admirable as this pursuit may be it's just not reality with any modern equipment.At a time when I acquired scopes to fix unless full documentation was available I wouldn't touch them with a barge pole yet in 8 years of selling so called modern crap not one has failed outside warranty.

author: MadTux
author_rank: Frequent Contributor
timestamp: September 26, 2021, 09:18:20 pm
content: Quote from: nctnico on September 26, 2021, 04:36:41 pmLOL, just earned 500$ fixing old machinery and used a Tek7854/7A22 for measureing signals on servo amplifierTry that with china aligarbage and have fun with your smoking pile of crap!

author: nctnico
author_rank: Super Contributor
timestamp: September 26, 2021, 09:47:52 pm
content: Quote from: tautech on September 26, 2021, 08:59:28 pmThe reality is that there is a lot less in a modern DSO that can fail. And if something fails, then it is likely power supply related and power supplies are easy to repair even without schematics. What is also a good way is to get datasheets for the chips used. Usually there is a schematic in there with the typical application. More often than not the circuit in front of you is the same.

author: MadTux
author_rank: Frequent Contributor
timestamp: September 26, 2021, 10:11:38 pm
content: Sure and if the PSU fails in catastrophic mode, like the one in HP9825 from Curious Marc and feeds overvoltage to all the digital stuff, because some beancounter saved a few pennies at the crowbar circuitry, you're in big trouble.Furthermore it's far from always PSU trouble, if it has corrupted firmware, dead flash/antifuse FPGA or some ASIC decides to fry, have fun with your $$$ brick, especially if it's made by Keysight, who is known to give a shit about people with their old instruments.If old school analog scope gets bricked, it's easy fix 99% of times. In the other 1%, I can get a new old one cheaply from ebay and use the other one as a source for parts. If recent, expensive DSO fries, not much source of parts, except you have 20'000$ BGA soldering machine to change ASICs.It's also that in maybe 80% of cases, an old analog scope is all that's needed, then maybe 10% where digital storage is handy and the other 10% where neither works, because you need a logic analyzer or you just can't probe the signals.But with old scope, you get reliability, price, fixability and great universal plugins (Tek 7000 and 5xx), which you don't have on new stuff.

author: BrokenYugo
author_rank: Super Contributor
timestamp: September 26, 2021, 10:26:11 pm
content: Do you want to repair scopes as a hobby, or own one as a tool?I'm reminded of the last few old guy holdouts who insist on driving pre EFI vehicles "I can fix points ignition or a carburetor roadside", they sure can, as can I, and I sure can drive on by in my more modern cars that have never stranded me due to an ignition or fueling problem.nctnico makes a very good point, failure in this stuff is likely to be power supply, and these modern DSOs run off a far simpler supply than an old analog scope.I wouldn't put more than $50 USD into a low bandwidth CRO to be used as a tool.

author: Runco990
author_rank: Frequent Contributor
timestamp: September 26, 2021, 11:05:47 pm
content: Well, you could pick up one of these. Stupid simple, very reliable, super simple to work on.Usually they develop a few cracked solder joints.A simple work horse. And still pretty cheap. As simple as it gets.

author: kcbrown
author_rank: Frequent Contributor
timestamp: September 27, 2021, 12:29:26 am
content: Quote from: ChrisThePackRat on September 26, 2021, 03:38:43 pmIt's not clear to me how this makes your scope irreparable. Can you post a photo of the scope so that we know what you're up against here?It's an old scope so at most I'd expect you'd have TTL logic chips to deal with for some of it, but more likely it's all just jellybean analog parts with the occasional opamp thrown in. If you've already found the dead component(s) then it's just a question of determining what they are and what the suitable replacements are.I likewise wouldn't expect it to make use of multilayer boards, which is about the only thing I can think of that would make tracing the circuits involved difficult.And seeing how you're looking for a scope that is going to require roughly the same level of skill to repair anyway, where theonlydifference is the availability of schematics, it seems reasonable that you should attempt repair of the scope you have.Of course, if you need another scope in order to be able to repair this one (a distinct possibility), then of course your question becomes rather relevant. But if that's the case, you can just as easily pick up something like one of the new Owon HDS242 scopemeters for less than $200. With that you get ahighlyportable (because it's handheld) 2 channel scope with basic triggering and 40 MHz bandwidth, which should easily be enough to make it possible to troubleshoot and fix your existing scope. And because it's handheldanda DMM, you may find that it's more useful than any old analog scope would be, just due to its convenience.Either way, you've got lots of options, but in the end I'm having trouble seeing why you can't just fix the one you've got.One other thing: if you can find another identical scope, you can just pick that one up and use the current one as a source of parts if nothing else.

author: Fungus
author_rank: Super Contributor
timestamp: September 27, 2021, 04:33:28 am
content: Quote from: MadTux on September 26, 2021, 09:18:20 pma) Nobody's suggesting the $50 crap DSOs. For a Budget of 300 pounds you can get a Rigol or Siglent.b) Maybe you need to revise your probing technique. A bit of basic knowledge goes a long way instead of crossing your fingers and hoping the 'scope can take it.

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 27, 2021, 05:07:01 am
content: It was an off-brand version of a Telequipment D54/55. Only label on it was Electroplan, which I couldn't even find any history for never mind a manual.I got the smudgy scans of the telequipment manual but the boards and components didn't match up at all between the scope itself and the manual from what I could make out. I figure it was cost-cut version of the original design.Along with the ropey documentation, there was no clear culprit to the issue. The trace was speed up on one side of the display and eventually the trace was gone entirely. Inspecting it on and off for a few days revealed nothing. I eventually gave up and flogged it online. I hadn't found one like it before or since.That's chiefly why I'm looking at a new scope with the capacity for maintenance and repair. Whether it's analog or digital doesn't much matter as long as it can be fixed if and when it's outwith warranty.

author: tautech
author_rank: Super Contributor
timestamp: September 27, 2021, 05:55:01 am
content: Quote from: ChrisThePackRat on September 27, 2021, 05:07:01 amAnd where you trying to diagnose such a fault without another scope ? Good luck with that !Sweep problems are not that uncommon especially in CRO's of that age however it's also uncommon to need a manual to fix them if you have a handle on the operating principles of a CRO for which a timebase sweep is just a timed linear ramp waveform driven to an offset and applied to the horizontal plates where in most points in the circuitry it can be quite simply be fault found from either the plates or the sweep gen......but you need a scope !My first scope was a Telequipment D83 and apart from its needle sharp trace I don't miss it a bit and have left CRO's behind where they belong ..... in scope history.

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 27, 2021, 03:42:55 pm
content: Yeah no luck, and I didn't have the money at the time for another scope.So now I'm looking for something better documented, so I don't have to go hunting for a blurry, tangentially related manual for something with no history.Any recommendations?

author: Keith956
author_rank: Regular Contributor
timestamp: September 27, 2021, 04:19:40 pm
content: Tek 465B? I have one I bought about 30 years ago, it was probably 10 years old then, and has been very reliable. And there are enough of them around that spares can be found. I have other scopes but it's still a workhorse.

author: Andrew_Debbie
author_rank: Frequent Contributor
timestamp: September 27, 2021, 05:56:05 pm
content: As others have said, you need a working scope to troubleshoot whatever you buy. So you need two, not one.Tex 465, 545, 535, 7000 series, -- whatever you find on eBay at a reasonable price and is inside your comfort range for repairs. They pretty much all have hard to find parts. Some more than others.Or you can buy a disposable Hantek as your 'second' scope.

author: PaulAm
author_rank: Frequent Contributor
timestamp: September 27, 2021, 07:04:23 pm
content: Heck, you could go older than that with a Tek 453 or 454. I have a 453 I still use often and I have NEVER had to open it up, it just keeps on running. My favorite of that series is the 454A and I managed to snag one off of craigslist for $25 a couple years back. I'll get around to restoring it one of these days.The only real unobtanium parts are tunnel diodes and a) they do not fail very often but b) you can find them if you look hard enough. Everything else is discrete. I've never had to replace any of those, either. The early ones used nuvisters, later ones used FETs if that makes any difference.I'm not completely in the dark ages, I have a LeCroy 1 GHz DSO which I love and wouldn't trade , but 90% of the time the cheap Tek is all I need.

author: tautech
author_rank: Super Contributor
timestamp: September 27, 2021, 08:56:03 pm
content: Quote from: ChrisThePackRat on September 27, 2021, 03:42:55 pmOnce I was in exactly your shoes and quickly learnt that despite the great old manuals available there was only so far you could go fixing a scope without another one.Schematics with DC voltages listed really help but only so far as things like sweep linearity can only be checked with another scope......as you discovered.So after investing in my first DSO many more scopes were able to be taken on for repair however the reliability of older scopes was always a problem however many owners of them probably didn't have the sad run I saw with many but you have to decide if you wanna have to repair your scopebeforeyou can tackle a project which only adds to blood pressure and frustration in your pursuits in the fabulous industry.Your budget is quite sufficient to get you a quite reasonable DSO which will give many years of trouble free service.Dip your toes in the water and come on in, the water's fine.

author: DBMandrake
author_rank: Contributor
timestamp: September 27, 2021, 10:15:48 pm
content: Quote from: Fungus on September 26, 2021, 04:20:14 pmQuote from: tautech on September 27, 2021, 08:56:03 pmI can relate to the sentiments of the original poster, but time has really moved on in scopes...In the 80's through to early 2000's I used a variety of reasonable spec analogue scopes for repair/project/ham radio uses - the usual suspects like Philips, (PM3262) Tectronics, (can't remember the model numbers of those) dual channel delayed timebase 100Mhz etc etc, for their day they were decent and worked fine, certainly for repair/troubleshooting work on mostly analogue circuitry.Then in 2009 I packed my bags and moved across the world and the bench Tectronics scope I still had at that time had to be let go as it was too bulky and expensive to ship overseas in relation to its low value by that time... the only scope I kept, which surely must be a curiousity item / museum piece now, (and a feat of miniaturisation in 1979) was a battery powered Non Linear Systems MS-215:http://www.byan-roper.org/steve/manuals/NLS/Non-linear_Systems_MS215_Miniscope_Manual.pdfDespite now being 42 years old (and over 20 years old when I first came into possession of it) it still works fine, aside from the sealed gel cell batteries which have failed for a 2nd time in the 20 years I've had it due to lack of use letting the cells discharge and sit discharged.So someone wanting an old analogue scope to "play around with" which has a schematic which is easily understood and repaired might have fun with one of these - it even has a full circuit diagram in the owners manual!For the last 10 years I haven't had much need for a scope so I've made do with the MS-215 for the occasional mostly audio work on my own equipment, but obviously there is only so much you can do with a 2" screen.Recently I needed to repair some audio equipment and realising the gel cells in the MS-215 had failed again and I couldn't be bothered trying to source replacements I decided it was finally time after about 15 years to treat myself to a half decent new scope (and try to get back into electronics more as a hobby) and had a look to see what was available.That's when it really hit me how much scopes have moved on in the last 20 years and that analogue scopes are basically dead and buried during my absence.Of course there were digital scopes 20 or more years ago but not in the price range of your average repair technician, (you looked at them in glossy magazines but didn't own one...) they had significant limitations for analogue signals, and were more useful for their storage / single shot capture abilities but weren't ideal for analogue work especially high RF.That has all changed. I started out looking at the ubiquitious Rigol DS1054Z as a friend has one, then I found out about the Siglent SDS1104X-U which is basically the same price but arguably a better device, then finally I stretched myself to the SDS1104X-E on the basis that it had additional features that could be unlocked over time that the SDS1104X-U didn't have, as well as better sampling with multiple channels and a few additional features.So while it was undoubtedly massive overkill for the specific use I had in mind that pushed me to buy a new scope, I was thinking ahead for other things I could use it for and I have already used it for several other applications with great success.Even though it's still only a low to mid "entry level" scope I'm in love with it and it blows me away what it can do compared to the scopes I've owned in the past that have all been analogue. Even simple stuff like single shot capture and hold or roll mode for very slow signals (which can't be shown on standard persistence analogue scopes) are features that I would have killed for 20 years ago. There are so many features packed into this device it's an unbelievable bargain.Of course lower end digital scopes do still have some minor drawbacks - the 8 bit A/D resolution can bite you if you're not aware of it - particuarly apparent in X-Y mode, and you need to learn and understand the relationships of sample rate, memory depth etc, to get the best out of it vs an analogue scope where you're really only thinking about timebase and risetime performance of the scope/probe. So there is a learning curve, but it didn't take me long.This scope will do everything that any scope I've owned before will, do it better and do 10x as many other things on top of that. In some ways I wish I'd made the jump a few years ago, on the other hand I didn't really have a need until more recently and the last 5 years seems to have been a particularly good time for entry level DSO's where the prices have come down dramatically and performance has gone up dramatically to the point where it becomes a no-brainer.To the original poster - by all means find a cheap analogue scope as something to play around with - I won't be getting rid of my MS-215 any time soon, and one day I will replace its faulty gel cells to get it working again as I still think it's a kinda cool relic of the past due to its tiny size and portability, but for actual work and getting things done a modern DSO - even a good entry level one like the SDS1104X-E is simply amazing compared to any analogue scope you will have used and you won't be disapointed. It's a completely different world.

author: james_s
author_rank: Super Contributor
timestamp: September 27, 2021, 11:13:36 pm
content: Repairable in the sense of having schematics and service information available pretty much limits you to vintage analog scopes from companies like Tek and HP, you're unlikely to find much newer than about 30 years old that has the sort of documentation you're requesting. A Tek 465 or 465B is probably a good fit for what you want and you ought to be able to find a nice working one within your budget.It's hard for me to recommend that over just buying a new Rigol DS1054z which is can be found brand new within your price range and is not likely to need repair but if you are really set on getting a scope you can tinker with, Tek was the undisputed king of analog oscilloscopes.

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 28, 2021, 12:40:11 am
content: Can you recommend something more modern that boasts a similar level of repairability?I think I'm being misunderstood here. I'm not nostalgic about older scopes. I just happened to have one at the time because it was what I could afford.Old or new, I want something that can be fixed in the event that it breaks. If it's in warranty, sure I'll send it away but if it's not I don't want to be part of the throwaway culture. I'd rather be able to fix it.

author: james_s
author_rank: Super Contributor
timestamp: September 28, 2021, 12:52:19 am
content: The problem is that what you're asking for (and what I too would like to have) is not how the world works anymore, not for a long time. Most electronic equipment stopped being designed for component level repair around 30 years ago, my TDS3000 scope for example was a very expensive instrument when it was new and the "service manual" if you can call it that is very sparse, has no schematics at all, just some mechanical diagrams and troubleshooting flowcharts to help you figure out which board or subassembly to swap out. Modern equipment is highly integrated, full of custom and programmable components and it's very rare to find something that has a schematic available. The only reason people are suggesting vintage instruments is because those are what meet the parameters you requested. I'd love to give you a suggestion for a <10 year old scope that has a real service manual available but I don't know of one. In a nutshell, you're looking for a unicorn.

author: bdunham7
author_rank: Super Contributor
timestamp: September 28, 2021, 12:52:58 am
content: Quote from: ChrisThePackRat on September 28, 2021, 12:40:11 amWell, that's sort of up to you, isn't it? I work on a variety of scopes, nothing to exotic, and they all have their issues. If you are looking at something with complete schematics available as well as a wide enough following that you have some chance of finding parts for the next decade or so, than Tektronix 22xx or 24xx series scopes would seem to me to be the option that fits that goal the best. However, even though fixing more modern stuff often means making do without complete schematics, the scrounging for parts and troubleshooting isn't much different. Again, the key is to get something fairly popular so that there are both repair methods and parts available in some sort of community. And no matter which way you go, you have to live with the fact that some--many--things are just not repairable unless you have a donor.The only remaining question is do you want something that can be fixed or that needs to be fixed now? If you go with an old CRT analog scope, it is much more likely to be in the latter category--I simply don't see very much that is in good shape and the junk ones still go for way too much money.

author: bdunham7
author_rank: Super Contributor
timestamp: September 28, 2021, 12:59:01 am
content: Quote from: james_s on September 28, 2021, 12:52:19 amhttps://www.bkprecision.com/products/oscilloscopes/2120C-30-mhz-dual-trace-analog-oscilloscope-with-probes.htmlI believe BK Precision will still give you a service manual if you ask. This isn't a recommendation!

author: james_s
author_rank: Super Contributor
timestamp: September 28, 2021, 01:02:28 am
content: I think it's quite impressive that those are still available. I'm curious whether they're still actually made or if they just have a pile of old stock in a warehouse that they're continuing to sell. If they are still made, I wonder if they're still making the CRTs or whether they've got old stock of those that they're using up. I imagine basic CROs like B&K sells are slow movers, given what they cost they must only sell a handful of them a year, maybe schools still buy them?

author: tautech
author_rank: Super Contributor
timestamp: September 28, 2021, 01:09:01 am
content: Quote from: james_s on September 28, 2021, 01:02:28 amTake your pick from this lot and the few I priced from them recently would have you buying a far better DSO for less $http://www.pintek.com.tw/product_classify/landersound-tail/index.php?Product_Site_Classify_SN=16856&Company_SN=6002

author: tautech
author_rank: Super Contributor
timestamp: September 28, 2021, 01:27:58 am
content: Quote from: DBMandrake on September 27, 2021, 10:15:48 pmQuite so and a massive step up from early DSO's and so well featured they cover almost all use cases but in doing so are more than many customers need although your decision to go with an instrument you can grow into is wise.While that sounds like upsell talkthe X-U you mentioned is also a good choice and one we try to offer them first as X-U is somewhat cheaper but very likely to serve the majority of normal scope needs and save them a few bucks in the process.

author: kcbrown
author_rank: Frequent Contributor
timestamp: September 28, 2021, 03:09:49 am
content: Quote from: ChrisThePackRat on September 28, 2021, 12:40:11 amNo.Anything, and I meananything(well, aside perhaps from that BK Precision one that was linked to), later is going to have unobtanium magic ASICs that simply cannot be "repaired".QuoteOK, the deal is this: whether or not something can be fixed is more a matter of what specifically is broken in the first place than anything else. For instance, if the issue with a modern scope is in the power supply, it can almost always be fixed at the component level. If the issue is with the display itself, then the display can almost certainly be replaced (replacement LCD panels tend to be more or less widely available, and for some scopes there are even projects for upgrading them. See, e.g.,https://www.eevblog.com/forum/testgear/gw-instek-gds-1000b-7-inch-to-8-inch-display-upgrade/). The analog frontends tend to use widely available components so fixing them isn't a problem as long as you are willing to reverse engineer them, and honestly there's a chance that something like that has already been done and, if not, it's something that people here seem willing to assist with.There are other failures that obviously can render the scope irreparable, such as a failure in an FPGA. But aside from failures in the high-complexity components such as FPGA, CPU, RAM, etc., everything else is jellybean parts or otherwise relatively easily replaced parts (and even some of the more complicated ICs such as RAM are likely to be replaceable). Even things like the A to D converters can often be replaced if necessary, especially if you're talking about a Siglent or Rigol scope where they picked off-the-shelf components for these things.Perhaps the most crucial piece in these modern scopes is the flash ROM. Lose that and you'll be dead in the water unless you have backed up the data on it. But that's something that you can actually do if you really want to. Many (most? All?) of these scopes have JTAG headers and the flash ROM chips themselves are (at least that I'm aware) reasonably standard. You might even be able to attach a header to the chip and read its contents directly. Modern scopes are digital devices, so working on them is more like working on a computer than anything else, except when the failure is in something specific to scopes like the analog frontend or the data acquisition subsystem.What you obviously won't get for modern scopes is schematics from the manufacturer. But that's already true of pretty much every scope made in the last 30 years already. The Tektronix TDS-200 series scopes, for example, which are already nearly20 years old, don't have any such thing. Here's the service manual for those:https://download.tek.com/manual/071049203.pdfEven those few reasonably modern scopes that have schematics are going to have unobtanium parts, perhaps more so than even modern scopes from Siglent, etc. HP and Tek both made extensive use of their own custom ASICs back in the day because that was necessary in order to achieve any sort of reasonable performance. These were DSOs made back when the fastest CPUs available were running in the tens of megahertz.So the bottom line is this: themaindriving factor in how repairable the scope will be won't be the presence or absence of schematics, but instead will beyour own skill. And you have a wealth of experience and knowledge to draw on here in the forum.Now, if you insist on having schematics for your scope after all that, well, that's your call. But from where I sit, I see norealadvantage to itexceptif you go with a fully analog scope with no ASICs or anything else. And save for that BK Precision scope, that's almost certainly going to be something that's more than 30 years old.

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 28, 2021, 03:57:02 am
content: Oh well, I suppose my bubble is indeed burst. Can't blame me for wanting something new with longevity in mind.Hopefully the Right To Repair movement isn't just hollow and designers starts speaking up in favour of it.I suppose without the qualifier of repairability, what would you recommend for a dependable modern scope in my budget?I'm not looking for anything fancy. The less controls, nested menus with bells and whistles, the better.

author: bdunham7
author_rank: Super Contributor
timestamp: September 28, 2021, 04:09:08 am
content: Rigol DS1202Z and Siglent SDS1202X-E are within your budget.

author: Fungus
author_rank: Super Contributor
timestamp: September 28, 2021, 04:22:07 am
content: Quote from: ChrisThePackRat on September 28, 2021, 03:57:02 amIt's not about "longevity" or "throwaway culture".Modern 'scopes don't wear out. There are no Rigol/Siglent repair threads on here because the Rigols/Siglents aren't breaking. Those old scopesneededschematics because they were constantly failing due to heat, high voltages, CRT tubes and mechanical switching."Right to Repair" is all very well for things with batteries and screens that get dropped but that doesn't really apply here.

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 28, 2021, 06:27:12 am
content: Why doesn't it apply? If I own it, should I not be within my rights to service it?

author: kcbrown
author_rank: Frequent Contributor
timestamp: September 28, 2021, 06:41:21 am
content: Quote from: ChrisThePackRat on September 28, 2021, 06:27:12 amYou certainly should have the right to service it, but that doesn't obligate the manufacturer to assist you with that. Supplying schematics would be precisely that kind of assistance.You should have the right as the owner of the equipment to disassemble it, figure out how it works, alter it however you please, etc. That, of course, includes repairs. If you can get the parts (again, something the manufacturer isn't obligated to assist you with) then you should be able to repair it.I do think it's in our best interests to reward manufacturers for making their products more easily serviceable, but that's a separate question, and in any case is something that can obviously factor into the purchasing decision.

author: james_s
author_rank: Super Contributor
timestamp: September 28, 2021, 07:27:00 am
content: Modern test equipment is on average at least as reliable as it ever was. Maybe you can't fix it easily if something major breaks but in return it rarely ever needs to be fixed and you could buy about 10 Rigol or Siglent 100 MHz scopes for what a single 100 MHz Tek scope cost back in its day even before you factor in inflation. It's just not really possible to get something that meets modern expectations for performance without it being so complex and tightly integrated that old fashioned component level repair with schematics and circuit theory is not feasible. And a lot of the stuff that breaks even today you can still fix if you are so inclined, whether there is a schematic available or not. For a scope the most common problems are things like the power supply and (if abused) the analog front end. I can guarantee you that any modern DSO is going to be much less likely to break down than any analog scope you can get.

author: 2N3055
author_rank: Super Contributor
timestamp: September 28, 2021, 07:42:11 am
content: Quote from: ChrisThePackRat on September 28, 2021, 03:57:02 amAs many here already said, new modern scope are much more reliable compared to old ones. Once in a discussions here, over 1 milion hours MTBF was mentioned from one manufacturer. Looking at how many are out here and general lack of problems I would presume that would also hold for most of them, including Rigols and Siglents.Reason for it is that today scopes are much better integrated, no mechanical switches and pots, no high voltages, and no parts like CRT that dies a little every day of use..All that means that in average hobby use, they will last for 20-30 years with no user effort at all.And after 10-15 years you can afford to buy new one for another 300-400 USD, which is going to be smaller, faster, better and smarter than new one (15 years of progress ..) and those 300-400 USD for a new one will be less than what you will spend for parts repairing the old one in that time.Also to point out the bad math: If you want to keep the scope for, say, 20 years from now, how old it will be then if now it is 20, 30 years old allready? How will you get parts then, when it is starting to be hard to get parts already, and people already ask high prices for parts and scopes.Also there is this "vintage" movement crap, where old crap is called "vintage gold". With prices to match.I would be glad if you could do what you want. And, maybe 10-15 years ago what you asked would make perfect sense.But, I'm afraid, today, that is one of those dreams that died in meantime and it is time to wake up.Right to repair means squat when it is cheaper and smarter to buy new, better one, than repair.There are no GOOD old scopes to be had. Reparability of 40 year old equipment is very bad despite available schematics.Things that are failing are mechanical (those are custom and no new replacement is available), old semis are not available (not being made anymore). Even then there are many scopes with custom hybrids and chips. No source for these either.CRTs are not available new.So you end up repairing stuff with parts from sketchy sources or with reclaimed old crap that might not be in much better shape than the broken one. Many parts are tired and insulation starts to breakdown, semis have suffered electromigration for 40 years etc etc.All the while, new inexpensive scope will be much smarter, with bigger screen, measurements and such. It will be the size of the loaf of bread and have 2 kilos, or the size of thick 10" tablet, also 1-2 kilos and will have battery and you could carry it around in one hand.You will get 3 years of warranty and it will last for at least 10 years without any effort on your side. If you do break or burn it, you can get a brand new one for the price that you will spend for parts repairing old clunker. Not to mention used time, and the fact that you don't have scope to repair broken one....Look around here, most of the people that own CRT scope today are those that have one or two and didn't use it in 10 years and keep it for nostalgia reason. And do all the work with modern DSO. I can relate..Other CRT owner group is people that have 4-5 or 20-30 of those, and they basically run a museum and spend most the time catering to the scopes. They don't use scopes for their electronics hobby, collecting and repairing the scopes IS their hobby.And there is nothing wrong with either of those two options.If you want to play with "vintage" scopes, then by all means, have fun.It's just you say you want a scope to do other things. In which case just go out and buy one of those DSOs people here recommended. They will do much better job than you need, they won't NEED any repairs for many, many years, and you will be able to do your hobby.Best,

author: Fungus
author_rank: Super Contributor
timestamp: September 28, 2021, 07:51:38 am
content: Quote from: ChrisThePackRat on September 28, 2021, 06:27:12 amSave your fight for the fragile, mass-consumed devices that are glued together with non-replaceable parts and one-off, limited-lifespan batteries.It doesn't really apply to a DSO which will last for decades if you treat it well.

author: Neutrion
author_rank: Frequent Contributor
timestamp: September 28, 2021, 10:34:47 am
content: I was wondering if the LCD backlight and its driver, or the hot running AD could be a weak point with modern scopes. Did anyone ever measured what temp. the AD's have in the cheaper Rigol, and Siglent products? In its datasheet there is no thermal data aviable, and most of the case they are not used with a heatsink.This is what it would make me think twice before slowing the airflow for the sake of some silence.

author: nctnico
author_rank: Super Contributor
timestamp: September 28, 2021, 10:49:39 am
content: Quote from: Neutrion on September 28, 2021, 10:34:47 amNot really. It is all LED backlight nowadays with very long lifespans. And the screens used are bog standard screens so replacements are easy to get for little money.

author: DBMandrake
author_rank: Contributor
timestamp: September 28, 2021, 11:30:32 am
content: Quote from: 2N3055 on September 28, 2021, 07:42:11 amWhile most of the components in a modern DSO outside of the large electrolytics in the power supply should have a relatively unbounded lifespan and don't really have a wear and tear failure mode as such, the one area of concern mentioned already in another post that I agree with is the nand flash memory, and this does suffer from wear and tear as nand flash memory has a limited write cycle life and will eventually fail when it has been written to too many times.This will render the device inoperable and potentially irreperable unless the chip can be replaced and some way to manually rewrite the OS directly to the chip can be found. (While some devices may have rom based flashing bootloaders that can re-flash a completely blank nand chip via normal user upgrade mechanisms there is no guarentee of that)I've worked with and helped develop other embedded arm based devices that use nand flash memory for their linux based OS and have seen the odd nand chip fail. One development device in particular the nand failed on me after 2 years but that device was constantly having the entire OS reflashed onto it for testing purposes which would have been more than 10x the normal write load of an in use device, so essentially an inadvertent accelerated lifetime test of the chip.How long the nand chip lasts will depend on the quality of chip used and how often the OS writes to the chip, which is partly up to the way in which the user operates the device. While I would expect it to last 10 years of regular use without issues I don't think we could safely assume it would last 20 or 30 years.A well designed system is going to have most of the filesystem read only with a small user data partition that is writeable which contains only user preference/configuration settings - this is the way the Siglent I have is set up for instance. So the write load is very low, largely just the scope saving the user settings when you do a soft shutdown, and things like screen grabs are being saved on external USB media rather than using up the write life of the nand. Unnecessarily doing frequent firmware upgrades/downloads of course would put a lot more stress on the nand chip.So while there is no specific lifespan of 99% of the components in a DSO, the nand definitely is a device that has a limited lifespan and will not last forever.

author: DBMandrake
author_rank: Contributor
timestamp: September 28, 2021, 11:47:15 am
content: Quote from: tautech on September 28, 2021, 01:27:58 amWhile I only occasionally dable hands on with electronics as a hobby these days, I did work professionally at it years ago so I think it's partly just me buying a scope now which has all the features I would have killed to have 20 years ago when I was doing it for a job...I came very, very close to buying the SDS1104X-U but changed my mind pretty much at the last minute. So the only one doing upselling was me, on myself.The main things that swayed me were the 1Mpt vs 128kpt FFT for the spectrum analyser mode, the option to add the digital inputs later, the web interface, the improved sampling rate with 2/4 channels in use, and the ability to hack it to 200Mhz (which I've done) that isn't possible with the SDS1104X-U due to the different front end.You're right, the SDS1104X-U is more than enough scope for nearly any hobbyist and I'm sure it would have done me fine, but I usually like to go one step above what I think I need to be future proofed.

author: tautech
author_rank: Super Contributor
timestamp: September 28, 2021, 12:06:14 pm
content: Quote from: DBMandrake on September 28, 2021, 11:47:15 amThat's what we are finding, most seem to get the dearer X-E however we did have a run on the X-U earlier this year.Have you installed the latest OS and firmware to get the new NTP clock and logging features ?Had to for 2 we prepped for dispatch today and getting pretty quick at it now along with installing our local NTP server address and setting a time location. Haven't had a chance to play with the Logging yet which I'm looking forward to after being beta tester for these X-E some years back and continually amazed at the functionality that keeps getting added.Many here on the blog also like the WiFi capability although it got busted with the latest FW we do have a properly working beta that we install for customers presale.

author: 2N3055
author_rank: Super Contributor
timestamp: September 28, 2021, 12:06:47 pm
content: Quote from: DBMandrake on September 28, 2021, 11:30:32 amRead again: 1 milion hours MTBF...Urban legend of pervasive flash rot was caused be nobody else but glorious Keysight. They initially designed very well liked and admired series of 2000/3000/4000 Infiniivision scopes with a code defect that would eventually lead to flash rot. Once they realized it's there they made changes and if you upgraded to new firmware it would not have problem anymore. Even that problem wasn't so bad, only people which didn't keep up with firmware updates had real chance of problems.I don't think if i ever heard that newer 3000T series had problem.And for that particular problem Keysight lived up to good reputation and if that happened to you, they would repair it free of charge.For Rigols I didn't hear about problem, Siglent had some problems with early scopes, but they made repair USB stick that sorts it out...Again, for the price, if after 15 (care free) years you simply chuck it in a bin and get a new one, for the price that is less than one (of many) repairs you will have to do in meantime on now horribly old crap that is literally falling apart..Every now and than, a topic here appears that goes like this: " after I didn't use for some time, I recently fired up my old (your favorite brand here) and it was dead.... ". there are dozens and dozens of those here...All the while i never had problem wih any of my modern scopes (half a dozen of those, from Rigol, Micsig Picoscope to Keysight.)A Picoscope 212/100 I bought in 2001 still works ...

author: AaronLee
author_rank: Regular Contributor
timestamp: September 28, 2021, 12:23:20 pm
content: Quote from: kcbrown on September 28, 2021, 03:09:49 amWhich is where a new scope might be more repairable than an older scope, from say 10 to 20 years ago. Some modern scopes may have ASICs, I'm not sure, but looking at Dave's teardown of Siglent scopes, I believe they all use off-the-shelf FPGA rather than ASIC chips. Of course, if you don't have skills in replacing BGA chips, that's meaningless, unless you want to pay someone to do that for you.On the other hand, if the FPGA chip last for let's say 40 years, 40 years from now that FPGA might easily become unobtanium even though it's no problem to get now. So if you truly want something that's repairable, you'd better stock up on any parts before they're obsolete, which of course is foolish, because then you're defeating the whole purpose of saving money by repairing it yourself, if you have to spend a lot on single-quantity devices which are expensive.

author: AaronLee
author_rank: Regular Contributor
timestamp: September 28, 2021, 12:33:22 pm
content: Quote from: DBMandrake on September 28, 2021, 11:30:32 amYup, if they're using NAND flash, you can guarantee it'll eventually be a problem. Perhaps so long in the future that you won't care, depending on your usage, and if the firmware was well designed. But firmware engineers that truly understand about wear-leveling algorithms and how best to optimize NAND lifetime are quite rare. With eMMC, instead of NAND, a lot of that is offloaded to the chip, rather than in the firmware, but you still need to be very careful about how you code your firmware with respect to flash memory usage.And again, even if you have everything that's necessary to write the bootloader and firmware to a new NAND chip, will a new NAND chip even be available when that time comes? Parts that aren't self-destructing can be salvaged from old gear. For NAND, I wouldn't even consider salvaging it unless I was really desperate, being you have no idea how much life it has left in it.

author: DBMandrake
author_rank: Contributor
timestamp: September 28, 2021, 12:47:01 pm
content: Quote from: 2N3055 on September 28, 2021, 12:06:47 pmThanks, but I've helped develop and test several devices that use nand memory and I'm intimately familiar with how it works, what its limitations are, and how to avoid over stressing at at a software level. (And have even had to develop a patch for a buggy nand linux kernel driver on one device where it wasn't implementing trim properly)The devices I've worked with are nothing to do with oscilloscopes so "urban legends of pervasive flash rot with keysights" means nothing to me, I'm simply talking about nand flash in general.The problem with nand failures is that it is sudden and somewhat unpredictable - it works perfectly up until the point where it suddenly doesn't work anymore. The one that failed on me was literally working fine one day and dead the next. The same goes for microSD card failures due to write fatigue - I have a whole bag full of microSD's with write fatigue failure that were re-imaged a lot during the same testing and lasted on average a couple of years.1 milion hours MTBF for the device as a whole doesn't really mean much in the context of nand write fatigue because you could leave the scope turned on for a million hours without turning it off and the nand may never get written to as it is likely to only be written on shutdown. (Seems that way on the siglent anyway) Or you could turn it on and off many times a day and wear out that nand a lot faster. Subtle changes or bugs in the software can greatly affect the amount of writes the operating system makes to the nand thus affecting lifetime.I'm not saying there is a massive problem or that I expect the nand to die on DSO's when they're a day over 10 years old... I'm just pushing back a little on the assumption that we should expect them all to be working fine after 20 or 30 years, as that can't be predicted and shouldn't be expected. Nand flash hasn't even been around that long...

author: DBMandrake
author_rank: Contributor
timestamp: September 28, 2021, 01:10:07 pm
content: Quote from: AaronLee on September 28, 2021, 12:33:22 pmHere's what dmesg has to say about the nand chip in the SDS1104X-E including the part number....Code:[ 1.228468] nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xda[ 1.234783] nand: Micron MT29F2G08ABAEAWP[ 1.238737] nand: 256 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 64[ 1.246308] nand: WARNING: pl353-nand: the ECC used on your system is too weak compared to the one required by the NAND chip[ 1.257802] Bad block table found at page 131008, version 0x01[ 1.264063] Bad block table found at page 130944, version 0x01[ 1.270169] 11 ofpart partitions found on MTD device pl353-nand[ 1.276025] Creating 11 MTD partitions on "pl353-nand":[ 1.281219] 0x000000000000-0x000000780000 : "fsbl"[ 1.287166] 0x000000780000-0x000000b80000 : "kerneldata"[ 1.293445] 0x000000b80000-0x000000c00000 : "device-tree"[ 1.299730] 0x000000c00000-0x000001100000 : "Manufacturedata"[ 1.306406] 0x000001100000-0x000001600000 : "reserved1"[ 1.312563] 0x000001600000-0x000003e00000 : "rootfs"[ 1.318538] 0x000003e00000-0x000004800000 : "firmdata0"[ 1.324731] 0x000004800000-0x000007000000 : "siglent"[ 1.330792] 0x000007000000-0x00000d400000 : "datafs"[ 1.336898] 0x00000d400000-0x00000fc00000 : "upgrade_cramdisk"[ 1.343824] 0x00000fc00000-0x000010000000 : "reserved2"£3.56 to buy one today, but in 20 years ?

author: Kleinstein
author_rank: Super Contributor
timestamp: September 28, 2021, 01:30:16 pm
content: Repairs with a moden scope are a bit tricky. The main part where is may work is the power supply (e.g. bad caps,...) and in some cases the input stages. Some of the cheap ones e.g. Rigol1054 get a way with mainly standard parts and could be repaired. For the more ADC / memory part, the small cases and BGA foot prints makes this usually a no go. Those who can still repair this usually want more than the cheap Rigol entry class.One may also want to have a scope to find the fault. With a broken scope you start with a limited set of tools.

author: DBMandrake
author_rank: Contributor
timestamp: September 28, 2021, 02:35:37 pm
content: Quote from: tautech on September 28, 2021, 12:06:14 pmYes I updated it to the latest firmware and yes, I noticed WiFi is broken now - I have a generic £10 TP-Link TL-WN725N which does work with the previous version but where I normally have the scope set up I have ethernet so I'll just stay on the latest version until a fix comes out.I've tried the NTP feature and it does work, however it's a little disapointing that you can only enter an IP address not a hostname for NTP as it's not normal practice to hard code public NTP servers by IP address...However poking around in the device via telnet it seems that not only is no name resolver configured, (no /etc/resolv.conf and no way to set a dns server via the UI) it does not even seem that there is any OS level name resolving compiled into the system:Code:ping google.comping: relocation error: /lib/libresolv.so.2: symbol __sendmmsg, version GLIBC_PRIVATE not defined in file libc.so.6 with link time referenceVery strange... hopefully they will add dns resolving in a future update to allow ntp to be a hostname.

author: BrokenYugo
author_rank: Super Contributor
timestamp: September 28, 2021, 05:00:29 pm
content: Quote from: DBMandrake on September 28, 2021, 01:10:07 pmIn 20 years that $500 scope will owe you nothing and you'll likely be able to buy an even better one for less money.That's how the world works now, stuff is largely disposable,and priced accordingly. A quick look shows that the Tek 465, which is less than half the scope a SDS1104X-E is, was introduced in 1973 at $1725, inflation adjusted that's north of 10k!

author: DBMandrake
author_rank: Contributor
timestamp: September 28, 2021, 05:16:23 pm
content: Quote from: BrokenYugo on September 28, 2021, 05:00:29 pmThat's kind of my point though. Anyone who buys a scope hoping to get 20 or 30 years out of it and be able to fix it after 30 years is crazy.There was a period of time from the 70's to the 90's where you could sort of argue that you could get 20 years out of an analogue scope because if you had a reasonably high spec one in say 1980 then apart from a higher bandwidth and maybe digital cursors an analogue scope of 2000 wouldn't be that much different, so as long as that 1980 scope was still working it was still useful. The Philips PM3262 my Dad bought in 1979 (which was several thousand dollars) was still in daily use up until around 2000 (when it suffered a voltage multiplier failure which zapped many of the analogue boards) for diagnostic repair work and was still perfectly usable for analogue work. So it did get 20 years of useful life without being totally obsoleted.That's no longer the case now as we're in an era where leaps and bounds of price/performance are being made. Any digital scope you buy today as great as they are compared with old analogue scopes will still be totally obsolete 20 years from now because you will be able to buy something so much better again for so little. As you say, after 20 years you've well and truly got your moneys worth out of your $500, and that would even be the case if you only got 10 years out of it.Would you keep a Windows PC 10 years ? Maybe. Would you keep it 20 years ? Nope. Bang for buck improves so much over a 20 year period in computers (and a DSO is just a special kind of computer) that there's just no point, for a reasonable cost you can get something that walks all over that 20 year old device and that progress is likely to continue for the forseeable future.

author: armandine2
author_rank: Frequent Contributor
timestamp: September 28, 2021, 06:44:32 pm
content: Affordable and Repairable - presumably the LeCroy Wavesurfer was for Ian - one of the "comments" basically asks him why he is so fortunate, the reply is of course that he is shrewd about the purchase regarding its repair prospects and the scope of his abilities to repair it.

author: kcbrown
author_rank: Frequent Contributor
timestamp: September 28, 2021, 06:51:54 pm
content: Quote from: DBMandrake on September 28, 2021, 12:47:01 pmI was rather under the impression that NAND flash generally had write cycle lifetimes measured in the hundreds of thousands. That Micron chip that Siglent is using claims 100K program/erase cycles in its datasheet:https://www.mouser.com/datasheet/2/671/micron_technology_mict-s-a0001032698-1-1759218.pdfEven if you're writing it once per day on average, it should last at least 250yearsif the claims of the datasheet are even close to being correct. Of course, getting that kind of lifespan out of it requires that you follow the manufacturer's recommendations at a minimum, and never screw that up.

author: Fungus
author_rank: Super Contributor
timestamp: September 28, 2021, 07:27:29 pm
content: Quote from: kcbrown on September 28, 2021, 06:51:54 pmFrom all the hacking that gets done here we know these 'scopes use partitions for their file systems, one partition for boot, one for the firmware, one for user data, etc.I can't say for sure how much flash-writing they do but it could be close to zero. Maybe a couple of things per boot-up.AFAIK there's no page/swap files or anything like that. Once it's running, it's running.How many times a day would you have to save a waveform or screenshot to wear out a flash chip in, say, 20 years? The number is ridiculous even if we assume no wear-leveling algorithms.

author: james_s
author_rank: Super Contributor
timestamp: September 28, 2021, 08:41:54 pm
content: Nothing lasts forever, and you never truly know what parts you'll be able to get into the future and what you won't. With a new scope the NAND flash may be a limiting factor, with an old scope the CRT will be a limiting factor, it is a consumable part that is guaranteed to wear out if you use it long enough, typically 20k-50k hours depending on quality, beam current and other factors. There are few if any factories building CRTs anymore and I think it is practically guaranteed there will be zero 20 years from now, at least for specialized oscilloscope CRTs. Ultimately we're talking a few hundred bucks here, not a major investment like a house that you may plan out decades into the future.

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 29, 2021, 01:55:13 am
content: Why would NAND be an issue?

author: tautech
author_rank: Super Contributor
timestamp: September 29, 2021, 02:00:35 am
content: Quote from: ChrisThePackRat on September 29, 2021, 01:55:13 amBecause Keysight made a botch of their SW and killed lots of it in some of their scopes so everyone is on tender toes that this doesn't happen in other brands.Little SW glitches are not uncommon however some brands have a library of SW tools to recover instruments should anything go wrong.

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 29, 2021, 04:03:00 am
content: Wouldn't the solution to that be to stick with a stable version and never update?

author: Fungus
author_rank: Super Contributor
timestamp: September 29, 2021, 04:21:39 am
content: Quote from: ChrisThePackRat on September 29, 2021, 04:03:00 amHow will you know if any particular version is wearing out the flash or not before it's too late?

author: kcbrown
author_rank: Frequent Contributor
timestamp: September 29, 2021, 04:34:45 am
content: Quote from: tautech on September 29, 2021, 02:00:35 amIt's not just that. NAND flash is one of the very few ICs that have an inherently limited lifespan just through use. Everything else is life-limited by other factors that are probabilistic, such as heat, cosmic rays, etc. (which, I might add, also affect NAND flash).So it's reasonable to focus on NAND flash over and above other components when assessing the life expectancy of a product. That said, modern NAND flash seems to have a rather large number of write cycles for its lifespan, enough so that unless it's heavily used, there's a good chance that one of the other life-limiting factors will come into play first.

author: Fungus
author_rank: Super Contributor
timestamp: September 29, 2021, 04:54:07 am
content: We need a thread where people sniff the buses of Rigols and Siglents and Keysights to see just how much writing is happening in normal use.I suspect it isn't much but the Siglents/Keysights seem to use Linux so you never know.(also my Micsig, which is Android)Some flash memory chips have built-in wear leveling so it might not be an issue even then.

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 29, 2021, 05:59:53 am
content: This is way above my level but what would be writing? I mean, if you're not saving settings or anything.

author: tautech
author_rank: Super Contributor
timestamp: September 29, 2021, 06:03:30 am
content: Quote from: ChrisThePackRat on September 29, 2021, 04:03:00 amWell certainly however all SW based instruments have bugs so to fix them you need update firmwareandthe progressive brands rollout additional features which too can only be gained by updating firmware.Pick your poison.

author: tautech
author_rank: Super Contributor
timestamp: September 29, 2021, 06:04:44 am
content: Quote from: ChrisThePackRat on September 29, 2021, 05:59:53 amEvery time a modern scope gets powered OFF user settings are saved so the scope boots ON as you last used it.

author: AaronLee
author_rank: Regular Contributor
timestamp: September 29, 2021, 06:35:33 am
content: Quote from: kcbrown on September 28, 2021, 06:51:54 pmThe thing is, vendors often choose to use one NAND chip for saving all types of data, including last memory data. Users are always complaining about systems where if you turn them off, they don't go back to the same previous settings, and rightfully so. The cheapest solution is to use NAND flash for this. Depending on the system (not just talking about scopes here), and how much the user is using it, if you save to last memory every time something changes, you could easily be writing to NAND hundreds of times per day for something with heavy use. Realize, any last memory needs to be updated every time you make a change to something stored in last memory. It's not every time you power on/off. 100K rated cycles for NAND @ 300 per day comes to less than one year. There are ways via software to greatly reduce the number of erasures needed, but the "standard" way for a firmware engineer, inexperienced with flash wearing, to code something like that would be to just erase and rewrite the last memory sector each time it needs updating, and will wear out NAND rather quickly under heavy use cases.A better solution might be to use a separate EEPROM or serial flash chip for storing last memory or other user data, thus greatly saving on NAND wear. Still, your EEPROM/serial flash chip might wear out eventually, but that's an easy fix, assuming parts are still available.Better yet, if you're not using a ton of memory for user requirements, design the device to use something like a battery powered SRAM, so the users can write to their heart's content without worries about wearing the device out.I've not studied the phenomenon much, but have personally experienced smartphone failures happening after just a couple years of use, and heard other complaining about it too, where the most likely reason for the failure, in my mind, is NAND which was written to beyond it's limits. Smartphones are perhaps an extreme case, but there's so many variables, and without knowing precisely how a scope's firmware was written, it's impossible to make any estimate about how long NAND flash will last.I'm not overly worried about the NAND flash in my scope, being it's only a roughly $1,000 scope. If it wears out after several years, I'll simply buy a new one, and get all the updated features that come out between now and then, which might even be worth it to buy a new scope regardless of whether my old scope still has life left in it or not. Look at smartphones, many of which cost as much or more than the scopes we're talking about here, and how people (in my mind often foolishly) upgrade to the latest model every year. I personally couldn't care less about the latest smartphone, being even a ten year old smartphone (if it could run the latest OS, which likely it can't) has more than enough processing power to do the very few things I require of a smartphone. But for people who are very dependent on their smartphone, perhaps upgrading so often does make sense. The same can be said for scopes. For someone who only uses the basic features, perhaps a scope bought now will still meet all their needs in 10 or 20 years. But for someone like me whose work relies heavily on using a scope, it likely doesn't make sense to hold onto it as their main device for so long, being they'll be able to become much more productive by updating to the latest technology much sooner than that.

author: AaronLee
author_rank: Regular Contributor
timestamp: September 29, 2021, 06:39:41 am
content: Quote from: tautech on September 29, 2021, 06:04:44 amThat depends on the design. Assuming the scope has a soft power off, saving settings only at power off time might make sense. If it's a hard power off switch though, that won't work. My experience with NAND chips and saving to last memory is mostly in devices I've designed that can be hard powered off at any time, in which case settings must be saved every time they're changed, not at power off time.

author: tautech
author_rank: Super Contributor
timestamp: September 29, 2021, 07:22:23 am
content: Quote from: AaronLee on September 29, 2021, 06:39:41 amCertainly interesting implementations both of them however if we run through a few types of instruments it becomes clear why some in the Siglent range in particular use one or the other OFF/ON switching.Eg, PSU's, AWG's and some of the old design DSO's use hard OFF whereas all their more modern DSO's have a soft OFF. Of course some types of instruments like PSU's and AWG's for example are adjusted less therefore it might seem NAND storage for every adjustment and a hard power OFF is a workable implementation that doesn't place too much demand on NAND wear whereas a scope we are constantly adjusting V/div, s/div and trigger levels let alone jumping into menus and such where a single save at power OFF seems much better NAND wear management.Fair assessment ?

author: AaronLee
author_rank: Regular Contributor
timestamp: September 29, 2021, 07:42:10 am
content: Quote from: tautech on September 29, 2021, 07:22:23 amYes, quite a fair assessment, I'd say. Though we still can't say anything for certain about how the firmware engineer implemented it. If they did only save at soft power off, it would greatly decrease NAND wear, assuming nothing else, besides the user settings, needs saving to NAND.Of course, if they do that, and the power goes off, or the user disconnects the power cord, settings wouldn't get saved. Some people like to connect their equipment to a power strip, and simply power everything off at once from the power switch, rather than powering on/off devices individually. If you did that, under a settings save only when soft power off, your savings would never get set. I haven't tested my Siglent scope to see what happens in that case, as I always soft power down first. I would be an interesting test to do on various manufacturer scopes, in an attempt to figure out at least some of their last memory save philosophy.What I personally do is have a last memory save timer in the firmware I design. Anytime a user setting changes, it sets the timer. So if during that time, the user changes the same or another setting, the timer gets set again. Finally, whenever the timer does expire, it saves last memory. If, for example, my last memory save timer is 5 seconds, any multiple changes within a 5 second period won't generate multiple writes to last memory, only one. If I was personally designing a scope's firmware, I'd analyze the the spec for flash memory, the size of my last memory structure and the size of the total sectors dedicated to last memory, the algorithm used, and come up with how many times last memory can be saved before the likelihood of flash failure will happen. Then divide that by a reasonable number, say 10, to be conservative. Then based on what the desired lifetime of the scope is, come up with how frequently last memory can be saved, and if reasonable, implement the last memory timer described, for people who might suddenly hard power off the scope, plus a fixed last memory save on soft power down.

author: nctnico
author_rank: Super Contributor
timestamp: September 29, 2021, 07:48:30 am
content: Quote from: DBMandrake on September 28, 2021, 01:10:07 pmWell, this is a major red flag.

author: tautech
author_rank: Super Contributor
timestamp: September 29, 2021, 07:51:30 am
content: Quote from: AaronLee on September 29, 2021, 07:42:10 amIt will boot to a previous power OFF save if not soft powered OFF.

author: Fungus
author_rank: Super Contributor
timestamp: September 29, 2021, 08:04:22 am
content: Quote from: AaronLee on September 29, 2021, 06:39:41 amThe Rigol DS1054Z has a hard power switch so it has to continuously save the current state, but it's saved in an I2C NVRAM chip, not NAND.(It's almost as if the designers knew about NAND chips wearing out...)

author: AaronLee
author_rank: Regular Contributor
timestamp: September 29, 2021, 08:07:05 am
content: Quote from: nctnico on September 29, 2021, 07:48:30 amNot necessarily.See this thread:https://www.at91.com/viewtopic.php?t=22917While they're discussing a different flash chip, it might be the same issue as the flash chip in the Siglent, and is simply a bogus warning message. Not saying it is or isn't, but before anything could be said about that warning, it needs to be analyzed.

author: AaronLee
author_rank: Regular Contributor
timestamp: September 29, 2021, 08:11:40 am
content: Quote from: Fungus on September 29, 2021, 08:04:22 amI wouldn't say, "almost". Any firmware engineer with any experience with NAND is going to realize real quick that NAND chips wear out and special handling is necessary, or else use an alternative to NAND. If a company designs a product and their engineers don't know about NAND chips wearing out, they'll likely not be in business for long, or at a minimum suffer a huge loss in credibility.

author: kcbrown
author_rank: Frequent Contributor
timestamp: September 29, 2021, 09:23:45 am
content: Quote from: AaronLee on September 29, 2021, 06:35:33 amThat's true. However, keep in mind that SSDs use the same NAND flash mechanisms and are capable of operating for many, many years of activity that is orders of magnitude greater than the activity generated against a scope's NAND flash even in the scenarios you're talking about.From what I'm reading, it appears that the cycle lifetime isn't with respect to the number of operations against the chip in total, but the number of operationsper block. Which is to say, each block of the NAND flash can tolerate up to 100K (in the case of the chip used in the Siglent) program/erase cycles. This means that you'd have to be writing the entire chip each time in order to see the numbers you were talking about.But in reality, these devices, including your scope, use flash-aware filesystems with wear leveling algorithms, TRIM, and all the rest. This means that, in reality, the life limit of the NAND flash is going to be determined by the cycle limit multiplied by the number of blocks in the chip, then divided by the number of blocks written per unit time, and the resulting number is going to be amuchlarger time than the calculations you did would imply. This is why SSDs generally work for as long as they do despite the fact that the computer is writing to it fairly continuously when it's running (it's writing logs and lots of other things as it operates). While the computer is writing fairly continuously, it's usually not writing a lot of data per unit time, and that's what keeps the SSDs from hitting their wear limits.So it's perfectly reasonable for the scope to be saving its state whenever you change it. You might change it a couple of hundred times a day, but each one of those changes will result in at most a single block in the flash chip changing, and each such chip will (if it's like the one in the Siglent) have 2gigabytesworth of available capacity, with a block size of 128K bytes, which gets you 16,384 blocks. And you don't need to erase a block until you've run out of blocks that are available to program. Programming blocks happens in pages, which are much smaller (2K), so if the unit were just writing the config and used an efficient format for that, it could go through amillionsuch writes before having cycled all of the blocksjust once.So I guess now, having done a bit of reading, I have to conclude that the NAND flash really isn't something to worry about when it comes to life limitations of the scope. You'd have to beat on ithardto get it to reach its life limits in something like a 20 year period. Chances are it'll last much longer than that. The Keysight issue was a very unusual one.

author: ChrisThePackRat
author_rank: Contributor
timestamp: September 29, 2021, 04:14:11 pm
content: So would you recommend that model or similar because of that design choice?

author: kcbrown
author_rank: Frequent Contributor
timestamp: September 29, 2021, 06:47:38 pm
content: Quote from: ChrisThePackRat on September 29, 2021, 04:14:11 pmAt the very least, I wouldn't recommendagainstit.But yeah, the Siglent scopes in general are very good. Nothing's perfect, and that's true of them as well, but in terms of build quality and hardware design, they're very good. Firmware (with respect to bugs) is a weaker point, but that's relative to A-brands like Keysight. I don't know of any issues with the basic functionality of the models I mention below. All of the bugs in these models is with respect to secondary functionality or odd corner cases, not the core functionality.For your budget (and even this is stretching it a bit), you'd be looking at either the 1202X-E or the 1104X-U. Either will get you far more capability than you've ever had with your previous scope, and likely far more than you'll even need. But that's really what you want: an instrument that won't stand in your way when you want to do something. Of the two, I'd probably go for the 1104X-U for the additional 2 channels, despite its slightly greater price. The additional channels are likely to be more valuable than the extra 100 MHz bandwidth that the 1202X-E offers.The Rigol 1054Z is a contender in the same price range, but it's an older design and doesn't, that I'm aware of, have any real capabilities that the Siglents above lack, aside from a bit more buffer memory which isn't, in my opinion, enough to overcome its shortcomings. I have both the 1054Z and the 1204X-E (which is really the same as the 1104X-U in every way that matters here) so I'm familiar with both. The Siglent is faster, more responsive, has better decoding (which may not matter to you), and is still actively maintained.If you were in the U.S., I'd also advise looking at the Instek GDS-1054B. But you're in the UK, so those are probably out of your price range.There may be other viable contenders but I don't know what they are or how they stack up.

author: rstofer
author_rank: Super Contributor
timestamp: September 29, 2021, 09:52:44 pm
content: I don't know any suppliers in the UK but Batronix handles the EU, generally. I also don't understand much about VAT except that it's stupid high.OTOH, a brand new Rigol DS1054Z from Batronix lists for $315 Euros. I don't know if VAT is included or extra...https://www.batronix.com/shop/measurement/Rigol-Oscilloscopes-PR.html

author: kcbrown
author_rank: Frequent Contributor
timestamp: September 29, 2021, 11:23:39 pm
content: Quote from: rstofer on September 29, 2021, 09:52:44 pmThat E315 is before VAT. After VATit's E375.After VAT, theSDS1104X-U is E427. And theSDS1202X-E is E403.

author: Neutrion
author_rank: Frequent Contributor
timestamp: September 30, 2021, 05:25:55 pm
content: Quote from: kcbrown on September 29, 2021, 06:47:38 pmThe 1204x-e has 2 ADCs, and the 1104x-u only one, and there are other differences. The 1104x-E is the same.Did anyone measured how hot the ADCs-are? I was thinking about putting heat sink on it but not sure how it could throw off the measurement.That is the problem also with slowing the airflow, the scope might works as well, but some components could run closer to critical condition.And one more thing: The 1104x-E when Dave reviewed had Rubicon caps in in the PSU. Than he reviewed later on a higher end one maybe the 2000-somethingish, and it seemed to have exactly the same PSU but without the Rubicon caps. Did anyone open a newer 1104x-E to check whether it still has Rubicons on the PSUs output side?

author: kcbrown
author_rank: Frequent Contributor
timestamp: September 30, 2021, 05:58:17 pm
content: Quote from: Neutrion on September 30, 2021, 05:25:55 pm(Just to be clear, the 1104X-E is the same as the 1204X-E in this)Yes, that's true, but that doesn't really make any difference for the situation here. The 1104X-U will still do 250 MS/s with all 4 channels active, which is enough to allow for proper reconstruction of a signal with frequency components going up to 100 MHz.QuoteThis is why I'm generally reluctant to replace the fan with one that would generate less airflow and pressure. The fan that is supplied with the unit has already been characterized by the manufacturer to cool the internals to levels that allow for reliable operation. Without actual measurements of the temperatures under the hottest conditions you'll use the scope in, you won't have any real idea whether the fan you're considering will properly cool the unit.

author: MathWizard
author_rank: Super Contributor
timestamp: October 02, 2021, 12:25:14 am
content: Quote from: james_s on September 28, 2021, 12:52:19 amYeah with modern stuff you have no schematic's, so u must map it out yourself, and look up chips, and hope the part names are on the chip, and on the web, and sold by anyone.Lots of old 20MHz scopes are pretty cheap tho, and the schematics are out there, I bet a lot of them are fairly repairable if some BJT or op-amp or cap gives up/out.Luckily I could afford a nice digital siglent1104x-e, that I hacked to a 1204. And it still works great. I plan to get a 2104X+, and hack it too.If they stop working, then its back to my 1980's scopes

author: vk6zgo
author_rank: Super Contributor
timestamp: October 02, 2021, 03:28:07 am
content: Quote from: BrokenYugo on September 26, 2021, 10:26:11 pmIgnition points have been gone for a very long time------even prior to EFI!I have definitely been stranded by a fault in a car with EFI, due to a plain old intermittent connection on the wire between the ECU & the distributor (yes, it still had an "old style " distributor & coil, but pulses from the ECU drove the "electronic ignition").The mechanic kept changing the ECU (Ahh! it's the computer!!') until I gave up on him & traced the fault with an old BWD analog 'scope.More EFI oriented, on the same car, a "Gorilla" incorrectly fitted an injector, causing the car to every now & again suddenly lose power at cruising speed.Re a "low bandwidth" CRO, most of the ones most people go for have at least 100MHz bandwidth.A new $50 DSO is likely to vary from pretty dire to just about unusable, really old DSOs are pretty useless for general work in analog electronics, & for some bizarre reason are costly, so are a waste of money.

author: vk6zgo
author_rank: Super Contributor
timestamp: October 02, 2021, 04:05:45 am
content: Quote from: Fungus on September 28, 2021, 04:22:07 amActually, there are a few---people have had problems with odd things on Rigols, not so much Siglents.QuoteConstantly? Nah!-------Most Tektronix & HP 'scopes went for decades without any problems.They were bloody expensive, though, & went mainly to large Engineering organisations, Broadcasting, or the Military.These bodies commonly required full documentation, as they had Techs on hand who could fix such things, when they, very occasionally, failed.If the Techs spent all their time fixing CROs instead of the stuff they were supposed to be working on, that supplier would miss out next time equipment was bought, so there was a definite motive to improve reliability.When you look at the "lower level" stuff, like the original Telequipment "Serviscopes", the lower bandwidth BWD, or even the cheaper Philips 'scopes, the documentation was pretty "sketchy"----- you got what you paid for!Even with them, the reliability was much better than your suggested "constantly".

author: MT
author_rank: Super Contributor
timestamp: October 03, 2021, 04:15:12 pm
content: Quote from: kcbrown on September 30, 2021, 05:58:17 pmNo they didnt do any characterization, not even a study of natural convection or fan went shape studies merely trowed in a el cheapo fan set at full speed, they could have used a silent fan for almost no added cost, they actually placed the fan at the wrong point. The air after many ours of use are barely detectable as warmer then the surrounding and the fan have terrible problems to get air out due to the clumsy inner outer case design. It would not surprise me folks could run this unit entirely without a fan or at very low speed and some added heat sinks here and there.

author: Neutrion
author_rank: Frequent Contributor
timestamp: October 03, 2021, 05:54:06 pm
content: I doubt they would not do any characterisation, otherwise they would risk a lot. Fan outlet shape - as long there is enough airflow- affects only the noise. An yes indeed it is not optimal.The fact that you can not feel hot air coming out (what did you measure by the way?) does not mean, that some components can not get closer to critical condition. So this is not a hair dryer.And speaking here about longevity, it can be, that the scope can run entirely without fan, but the lifetime could be reduced significantly.The reason why I asked about the temperature of the hmcad1511 is, because it consumes 720mW, is in a small package without heatsink, so it could be qiuet hot even with a lot of air. In the datasheet there is no word about life expectation, or general temp. management in the design.So it can be critical. There could be similar hot running stuff in the analogue frontend. How much does the processor consumes? (Zynq)And I did not check the datasheets of other components without cooling.I was also wondering how cooling of some componens like the ADC could affect the noise levels.

author: MT
author_rank: Super Contributor
timestamp: October 03, 2021, 06:21:45 pm
content: Quote from: Neutrion on October 03, 2021, 05:54:06 pmA closed compartment of metal gets hotter by time if there is enough heat generated inside it which in turn heats up plastic etc and the plastics are ice cold etc .Compare 1104 case design with other manufacturers and you will see. If something is critical you obviously design with that in mind and not put a fan 1 km awayand hope for the best. So no there is no characterization at all done on these small scopes the speed and position of the fan and even the dba specs on the fan givesit way. Plenty of space to slab a big azz cool fin across the ADC's if you want. More likely you would get much better heat removal performance by moving the fanto the other side close to the Zynk and ADC's and also much closer to PSU switching tranny cooling plate. The 1104 is a software crippled 1204 none of them runsat critical points you simply dont design consumer stuff that way if you are a proper engineer. Even Tautech suggest resistor in series to reduce fan speed.At 4:45https://youtu.be/Kay4Jk2DHuE?t=2851104x fan stuff:https://www.eevblog.com/forum/testgear/has-anyone-else-gotten-shrill-noisewhine-on-their-siglent-sds1104x-e/msg3390412/#msg3390412https://www.eevblog.com/forum/testgear/siglent-1104x-e-noisy-fan-replacement/

author: tautech
author_rank: Super Contributor
timestamp: October 03, 2021, 07:40:40 pm
content: Quote from: MT on October 03, 2021, 04:15:12 pmStudy my replies on this matter and for longevity convection cooling is NOT an option.https://www.eevblog.com/forum/testgear/siglent-1104x-e-noisy-fan-replacement/msg2983838/#msg2983838Equivalent Noctua fans have been tried and offer no appreciable advantage.The very similar SDS1202X-E with a single ADC uses a different and much quieter fan as its cooling requirements are much less. Early 1202X-E used the same fan but they were swapped out for a quieter model as part of product improvement.Quote from: MT on October 03, 2021, 04:15:12 pmAt the risk of thermal instability resulting in measurement drift while internal temperature stabilizes.Any airflow creates a more stable board temperature for which Quick Cal needs to operate less.

author: MT
author_rank: Super Contributor
timestamp: October 03, 2021, 08:19:10 pm
content: Quote from: tautech on October 03, 2021, 07:40:40 pmI didnt say they did, what i said they didnt study natural convection cooling , longevity is your words. Read what i said before taking things out of context and utteringQuoteSlowing the fan, there you go, and the rest is of courseno need to be Phd to measure internal temperatures to figure out the 1104 fan and its position is a piece of crap!Mine just weeks old already started to tick and wobble due to crappy bearings! Come on now Tautech , BS aside you know very well Signlent dont test their fans , just trows them in.No need to debunk the claimed ca: 26dba figure just point at the 1104 case design.http://www.szdosense.com/eng/products-detail.asp?cpid=177QuoteSo why not do a product improvement on the 1104 then? Siglent clearly has not paid any attention to the fan noise issue for the 1104 etc!QuoteSo therefore you dont put the fan 1 km away as Siglent have done, thereforeno air flow characterizationhas been done! You also have to prove this "risk" you claim "scientifically" in a long carefully done report.Fan put in the right position can remove exactly the same amount of air at less speed then current position i.e less fan noise! As pointed out here:https://www.eevblog.com/forum/testgear/siglent-1104x-e-noisy-fan-replacement/msg1541546/#msg1541546

author: bdunham7
author_rank: Super Contributor
timestamp: October 03, 2021, 09:00:19 pm
content: Quote from: MT on October 03, 2021, 08:19:10 pmYou are totally missing the point. I have not studied the SDS1104X-E internals, but in other applications and in general it is not necessarily the goal of the fan to 'remove' air or keep the overall internal temperature down. It often is the goal to circulate the airinternallyto cool specific components and reduce temperature gradients. There are cases of devices that are totally sealed and still have fans inside. You cannot judge the efficacy of the fan by the amount of air it moves to the outside nor can you assume that it is unnecessary because the exhaust air is not warm.

author: MT
author_rank: Super Contributor
timestamp: October 03, 2021, 09:24:41 pm
content: Quote from: bdunham7 on October 03, 2021, 09:00:19 pmNo, you missed all points because you slides in on bananashell talking about general obviousnesses which is not a point. Now in this oscope case imagine its 20 deg C inside but 30 deg C outside now go figure! In this oscope case you want to remove heat since the design is not made to maintain a perfect temperature i.e like a ovenized crystal reference. Maybe you should study the 1104 internals first before commenting.

author: MT
author_rank: Super Contributor
timestamp: October 03, 2021, 09:37:08 pm
content: Siglent had no problems adding cooling fins on the SDS2000 dual adc's. Surely folks can circularly argue about that as well!https://youtu.be/HxzQS-Bn2R0?t=417

author: 2N3055
author_rank: Super Contributor
timestamp: October 03, 2021, 10:04:31 pm
content: Quote from: bdunham7 on October 03, 2021, 09:00:19 pmThat is all correct.Turbulent airflow over heatsink fins surface actually removes more heat than laminar flow, because it removes air from boundary layer, that otherwise works as an thin insulation layer.Also if total amount of heat dissipated inside case is not very high, but there are hotspots, if you just circulate air inside case you will eliminate hotspots while still raising average temperature inside only few degrees, while exchanging inside air with outside quite slowly..A quote:"For thermal consideration, HMCAD1511’s QFN48 package’s thermal resistance is 29 degree Celsius/W, then the maxim temperature rise is about 20 degree Celsius. With a reasonable PCB thermal pad design for heat dissipation, there is no heatsink needed for HMCAD1511."from:"Readout System with 2-Channel 8-Bit 1GHz FADC Based on RAIN1000Z1 ZYNQ Module for Crystal Detector"Tao Xue, Member, IEEE, Guanghua Gong, Jianmin Li0.7 W is not very much, and multilayer PCB can cool it fine enough.

author: kcbrown
author_rank: Frequent Contributor
timestamp: October 03, 2021, 10:09:33 pm
content: Quote from: MT on October 03, 2021, 04:15:12 pm"Characterization" here means that they monitored the temperatures of the heat-generating components to ensure they didn't overheat. Apologies for any confusion.Do youreallythink that a manufacturer is going to include a fan if it's not necessary? It's an additional expense! They not only have to pay for the additional costs of the fan, they have to design the case to incorporate it, they have to incorporate a power connection for it on the PCB, etc. Itcosts them money, both in design and in implementation. They'd be morons to simply slap a fan in there and pay a per-unit cost for it when they can save themselves that per-unit cost with a little additional up-front one-time effort.And they have to characterize the component temperatures during operation anyway, because it's theonlyway they can know whether or not their design is going to hold up in the real world, becausefailing to do so means they risk getting a bunch of warranty claims, whichcosts them money.Could they have made use of a more silent fan? Possibly. But that's a very different thing from decidingwhetherto incorporate a fan at all. Of course, they have to measure the effects of whatever fan they select because it's the only way they can know that it's sufficient for their purpose.So yes,of coursethey characterized the temperatures of the scope internals, andof coursethey incorporated a fan because they perceived they needed to on the basis of that characterization, andof coursethey examined the effects of the use of the fan on the component temperatures to make sure it was sufficient. Only a complete moron would fail to do these things for ashipping product. It's not like this is some kind of extraordinary effort or anything, it'sindustry standard.Oh, and as for the choice of fan, any engineer worth his salt is going to select a fan that has more airflow/pressure capability than necessary, because good engineers build in margins into their designs to ensure reliability, guard against failure, etc. As applied here,of coursethat means the fan is going to be noisier than it has to be, because it'll flow more air than it strictly has to. But when it comes to the choice of more noise versus less (or no) margin, a good engineer will always go for the former as long as it doesn't violate the design requirements. Finally, even if there exists a quieter fan that achieves the same airflow and pressure differential, and even if it's "almost no added cost", it's still added cost, and for all you know it might be a substantial added cost to the manufacturer because bulk price differences can be very different than individual or small quantity price differences, not to mention that the manufacturer of the scope may well have a contract with the manufacturer/supplier of the fan so as to secure a better price. So the availability in the retail market of a quieter fan with the same airflow capabilities isn't of itself sufficient reason to conclude that the manufacturer made a mistake in fan selection.

author: bdunham7
author_rank: Super Contributor
timestamp: October 03, 2021, 11:40:17 pm
content: Quote from: MT on October 03, 2021, 09:37:08 pmCircularly? Perhaps Analog Devices called up Siglent to point out that stick-on heat sinks on top might not be all that helpful for a device with a large pad on the bottom.

author: MT
author_rank: Super Contributor
timestamp: October 04, 2021, 12:24:54 am
content: Quote from: kcbrown on October 03, 2021, 10:09:33 pmEasy to say claim now isn't it? This is one of the things you said previously perhaps in case you forgot:QuoteSounds like you talk about the fan alright which makes rest of your novel uninteresting to read more of a word salad defense, sort of.So obviously moving goal posts not even considering the thermal specs of the HMCAD1511, with your word saladTautechs spin down your fan with series resistorsuddenlydont count according to your preaching of "engineer worth his salt" "good engineers build in margins into their designs" etc, etc, and gobble ,gobble. Anyhow Tautech alreadyconfessed Siglent swapped fans to more silent ones in other units.Again, here is unsalty Evvblog engineers not worth their salt modifying 1104 fans due to noisiness and Tautechs spin down the fan mod!https://www.eevblog.com/forum/testgear/siglent-1104x-e-noisy-fan-replacement/msg2983838/#msg2983838

author: MT
author_rank: Super Contributor
timestamp: October 04, 2021, 12:27:15 am
content: Quote from: bdunham7 on October 03, 2021, 11:40:17 pmPerhaps, who knows!

author: tautech
author_rank: Super Contributor
timestamp: October 04, 2021, 12:45:46 am
content: Quote from: MT on October 04, 2021, 12:24:54 amConfession ? Actually a fact !Why shouldn't Siglent improve models if/when they can ?SDS1202X-E is in a lower class of performance to 1104/1204X-E and these later 4ch models require more cooling.Shoebox size entry level scopes with such capability and feature set need be adequately cooled so require a decent airflow.IME handling many of both these models there have been slight changes over the years and for the 4ch X-E's a lower consumption fan has been fitted in the last year or so.

author: kcbrown
author_rank: Frequent Contributor
timestamp: October 04, 2021, 12:47:12 am
content: Quote from: MT on October 04, 2021, 12:24:54 amWhich is why I apologized for the confusion. If that's not good enough for you then tough. Deal with it.QuoteHuh? Tautech was referring to what an individual can do with his scope after the fact, not what themanufacturerwas considering doing! An individual's environment can easily (and likely will) differ from the warmest environment the scope is specified to be able to operate reliably in.An individual can replace the fan with something quieter if he so chooses. It's his scope, he can do with it what he wants. I was only describing in my original message whyIam personally reluctant to replace the fan with something that flows worse than what the manufacturer supplies. That's just me. Others can do what they want.QuoteYes,in other units. It's likely Siglent received enough complaints about fan noise that they switched to a quieter unit with less airflow in the SDS1202X-E because they were able to actually get away with doing so. That doesn't automatically mean they can do that withalltheir models, and why in the world would you think otherwise? None of this negates anything I said previously.So why didn't Siglent just go with that quieter model in the SDS1202X-E from the start? Presuming they originally used the same fan in the 1202X-E as in the 1104X-E/1204X-E, likely because they already knew that the cooling demands of the 1104/1204 were greater and, thus, that the fan from that model would be sufficient for the 1202, and by selecting the same fan they would get better economies of scale, if nothing else. Obviously they would have tested the thermals with the 1104/1204 fan in the 1202 just in case.

author: tautech
author_rank: Super Contributor
timestamp: October 04, 2021, 01:00:20 am
content: Quote from: kcbrown on October 04, 2021, 12:47:12 amIt's likely they just used the same fan fitted in the older SDS1102/1202X. They ran an ARM uP whereas X-E run the more powerful Xilinx uP which for all I know could run cooler. AFAIK the older X models run the same ADC.However the X model did have a slightly larger enclosure, 8" display and had an internal AWG so needed the higher airflow of the earlier and noisier fan.

author: james_s
author_rank: Super Contributor
timestamp: October 04, 2021, 01:58:59 am
content: Manufactures upgrade products all the time. Back when I worked at a place that made hardware we regularly revised models, replacing components like fans, RAM, hard drives, etc. Usually for cost reasons but it could just as easily be done to make something quieter or to correct premature failures.