EEVblog #829 - Siglent SDM3055 Bench Multimeter Teardown

[EEVblog]

Inside the Siglent SDM3055 5.5 digit bench multimeter
http://amzn.to/1lBAD7b

[Muttley Snickers]

Apparently the expansion port was intended to be used for a scanner option for the SDM-3055S model which they did away with, the SDM-3055A GPIB model is supplied with a USB/ GPIB dongle and not a rear port which was shown in some early pictures.

https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/msg666922/#msg666922

[plexus]

So wait a minute. on one hand you say that its cheaper than the Agilent but it's not as well made as the Agilent. what do you want? you want these things to be built as well as higher priced models but you want them to be the same price? care to provide solutions to how this can be done? I can understand if you explain how they could increase the quality for the same price but you don't do that. you just say they aren't built as well as more expensive units as if they can do better. how? I don't understand the complaining on cheaper quality on a cheaper instrument but if you can tell us how they could provide higher quality for the same price that would be great.

[TheSteve]

So wait a minute. on one hand you say that its cheaper than the Agilent but it's not as well made as the Agilent. what do you want? you want these things to be built as well as higher priced models but you want them to be the same price? care to provide solutions to how this can be done? I can understand if you explain how they could increase the quality for the same price but you don't do that. you just say they aren't built as well as more expensive units as if they can do better. how? I don't understand the complaining on cheaper quality on a cheaper instrument but if you can tell us how they could provide higher quality for the same price that would be great.

The engineering design cost of the meter in China is probably 10% of what it would be if it was designed in the US - so they darn well better be able to sell it for less, even if the quality was the same.

[Armxnian]

So wait a minute. on one hand you say that its cheaper than the Agilent but it's not as well made as the Agilent. what do you want? you want these things to be built as well as higher priced models but you want them to be the same price? care to provide solutions to how this can be done? I can understand if you explain how they could increase the quality for the same price but you don't do that. you just say they aren't built as well as more expensive units as if they can do better. how? I don't understand the complaining on cheaper quality on a cheaper instrument but if you can tell us how they could provide higher quality for the same price that would be great.

Build quality is not the only reason the Agilent costs more. It has better specs, operational firmware, better support, and the name Agilent on it.

[Hydrawerk]

You mean Keysight.

[Armxnian]

You mean Keysight.

No, I mean Agilent, because that is the branding Dave's unit has on it.

[rdl]

I wonder how old Dave's meter is? I thought they claimed to have fixed the rust problem, but I saw it as soon as the cover slid off. The power supply in the last show was new and it had rust also. They are at serious risk of becoming a laughingstock (if not already) unless they fix that. What happens when particles of rust start floating around inside a so-called precision meter?

[lukier]

It seems that the case and the digital mains earth referenced logic (ARM CPU) is shared with SDG2122X. Maybe the case will be used in something else, therefore two holes for fans. Nice design from SKU and software development point of view.

For the price the hardware seems to be OK, rusty case & crusty soldering, but decent parts, input protection, guard traces etc. SDG2122X was OK too. Both much better than the PSU you showed recently. I suppose this must have been a different design team

I wonder why discrete 24 bit ADC. Nice chip, but these chips can be quite expensive. Since they have Lattice CPLD on board and using ADG switches elsewhere, wouldn't it be cheaper to do multi-slope instead?

[SeanB]

Rust problem is easy to fix, just take all the metalwork after the punching process, dip in a pickling bath, rinse then electrogalvanise then etch again and powder coat. Even a short pickle and electrogalv operation after the painting on complete cases would put a protective film on the cut edges.

More expensive would be a tumbling operation in a large drum to get the sharp edges off first.

[EEVblog]

So wait a minute. on one hand you say that its cheaper than the Agilent but it's not as well made as the Agilent.

Correct, I said it's cheaper than the Agilent and isn't built as well as the Agilent. I used the term Apples and Oranges comparison.
You then go on to make a point as if what I've said is somehow contradictory?

what do you want? you want these things to be built as well as higher priced models but you want them to be the same price?

I neither said nor implied such a thing.

[EEVblog]

I wonder why discrete 24 bit ADC. Nice chip, but these chips can be quite expensive. Since they have Lattice CPLD on board and using ADG switches elsewhere, wouldn't it be cheaper to do multi-slope instead?

Maybe, but you have the dick around getting it right. The 24 bit ADC just works and has known parameters.
Keysight have spent decades refining their own dual slope technique.

[TheSteve]

It's another teardown that makes me want the product less instead of more...

[tautech]

Thanks Dave.
Siglent SDM3055 thread:
https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/

[mikeselectricstuff]

I think you were way too hard on the build quality.
Surface rust, presumably a by-product of laser or waterjet cutting, is a non-issue as long as there isn't powdery rust falling off anywhere.
Airflow path looked perfectly reasonable to get a more stable temperature - probably not essential but for a DMM, stable temperature can't hurt.
The holes spread out around the divider looked like they should give a reasonable airflow over most of the board.
I see no problem with spade connector onto a flap in the metal, as long as it's not rusty and thickness is OK, and it's arguably safer as screws can come loose.

As for caps - has anyone actually done any proper tests on lesser brands ? Just because you've never heard of them doesn't mean they're not perfectly adequate for the job.
And of course they're very easy to replace if they do eventually die, so not really a big deal, less so where they're not running in a hot environment.




 

[funkyant]

So wait a minute. on one hand you say that its cheaper than the Agilent but it's not as well made as the Agilent.

Correct, I said it's cheaper than the Agilent and isn't built as well as the Agilent. I used the term Apples and Oranges comparison.
You then go on to make a point as if what I've said is somehow contradictory?

what do you want? you want these things to be built as well as higher priced models but you want them to be the same price?

I neither said nor implied such a thing.

When they do this:



It's fair game to be comparing the two, regardless of price point.

If they don't want the comparison made, they should design an original front panel.

[Wytnucls]

Lelon has four factories. One in Taiwan, two in China, and one in Malaysia (joint-venture business with Elna Japan). Total capacity is 820 million pieces per month and the company has 3000 employees.
Joint venture with Elna points to an acceptable product quality, I would presume.

[SeanB]

The internal case is punched with a die, which leaves those sharp edges. They probably also reuse the same case parts in other equipment, so you will find other Siglent equipment in the same form factor case will have the same chassis construction, and with the same mounting holes and cut out portions, or a majority, you can use a multipart die with removable punches in part to do special cutouts, but it is often cheaper to punch them all and simply not use those you do not need in the particular model. That explains the fan cutout in the 2 sides, they are a mirror image, simply turning the sheet over to do the end bends  on a separate set of dies. You can see the draw marks on the edges of the metalwork.

Centre is done with a 3 step process, first punches out the holes and the openings, leaving the holes with shaped edges for the second stage of punching them down 90 degrees, then the third stage rolls it over to leave the smooth edge. they then either spot weld or form a rivet ( did not look too closely to see the method of joining the panels, but this is the most common method that does not need any extra material or parts) to hold the panels together.

Ideally they want to tumble the panels after punching in an abrasive pumice bed, to dull the sharp edges, then wash, pickle in acid, wash again then thin electrogalvanise to coat the edges exposed in the forming. Probably the pickle and electrogalv would be done on the finished parts ( less the bright coated inserts) to have a nice internal chassis with smooth edges for assembly, pretty much all the final assemblers would have cuts from those edges.

Wonder if you ran a damp swab over the edges, put it in a PCR reactor then did DNA analysis if you could trace who was the last person to bleed over the unit.

As to the Lelon capacitors, in this use they really are only mildly stressed, as regular electrolytics in linear supplied have used non low ESR for decades, so they should have a good life. On the SMPS side with high frequency current heating they might have a shorter life, but here the ESR can ride quite high before it will become a failure. You see many old power supplies running fine with capacitors with ESR in the range of 1-5R and only thing is increased ripple into a linear regulator.

[Lightages]

I thought that it is OK build for the price. Except for the "rust" I don't see much to complain about. I might buy one if I were in the market for a 5.5 benchtop, especially since they sped it up with a firmware update.

[Groucho2005]

Maybe it's really humid in Dave's lab... 

[kalleboo]

Maybe it's really humid in Dave's lab... 

Clearly Dave has been slobbering all over the equipment!

[bookaboo]

Has to be said Dave is certainly not ever going to be influenced to give positively biased reviews... even if the CEO flies in personally and leaves a bunch of swag. Fair play for pointing out every niggle.

One thing that obviously struck me was the similarity to the Agilent/Keysight and it's implications for the future. If Fluke can get a batch of meters stopped at customs and banned for literally "being yellow" how and why are Keysight letting a competitor (albeit a lower end competitor) get a foothold using such a blatant interface rip off?
Don't get me wrong, I'm all for competition and I shed no tears for large corporations but this unit is just asking for a copyright infringement lawsuit!

[Kleinstein]

Copyright does only applys to really 100% copy - it does not protect things like the look and feel of the software or the arangement of the keys. In some countries there may be a kind of "small" patend to protect a design  (e.g. Gebrauchsmusterschutz in Germany), but this is expensive and only works locally.  So even Samsung got around the round corners of the IPad.

It's true that the design is rather close, but this might help users to switch in one way or the other - often user start with a low cost and upgrade. So even Keysight might profit from the similarity even if they don't like it.

One thing that did not look good to me is the rather close spacing from the guard lines to the reistors strings made for high voltage rating. If the guard is so close there is not much sense to the long string and the cutouts.

With the fan I wonder if it is temperature controlled ? At moderate temperatures I don't think the fan is really needed. It may be at 40 C ambient. So I would consider a fan just for the summer a good idea.

[nctnico]

I think you were way too hard on the build quality.
Surface rust, presumably a by-product of laser or waterjet cutting, is a non-issue as long as there isn't powdery rust falling off anywhere.
Airflow path looked perfectly reasonable to get a more stable temperature - probably not essential but for a DMM, stable temperature can't hurt.
The holes spread out around the divider looked like they should give a reasonable airflow over most of the board.
I see no problem with spade connector onto a flap in the metal, as long as it's not rusty and thickness is OK, and it's arguably safer as screws can come loose.

I agree. You only need a little bit of airflow move a decent amount of heat.
Also the remark about the front/display cable running through the transformer section makes no sense IMHO. I would not want such a cable anywhere near a potentially sensitive analog board so I'd consider it a plus they went through the effort of putting that cable on the other side of the shield and wrapping it with an insulator. Same goes for the remarks about the holes for the fans. This clearly is a standard casing for Siglent which they use for many of their devices (look at the SDG1000 series for example). What is wrong with that? Only a complete fool designs a case from scratch for every product. HP has been using the same aluminium front, rear and frames for decades.

[jitter]

Lelon has four factories. One in Taiwan, two in China, and one in Malaysia (joint-venture business with Elna Japan). Total capacity is 820 million pieces per month and the company has 3000 employees.
Joint venture with Elna points to an acceptable product quality, I would presume.

I can tell you with 100% certainty that Lelon caps are being used in industrial procucts that are designed AND manufactured over here. But having said that, it's much more likely that one will find Nichicon, Rubycon, Panasonic, Nippon/United Chemicon and last but not least Vishay/BC (formerly Philips) in those kinds of products.

With respect to the remark on the rear terminals on Keysight bench meters: imagine you're doing my work, i.e. testing and calibrating measuring instruments. Then having both front and rear terminals is very useful. On the front I connect standard testleads with clips that connect to test points on pcbs. On the rear I connect a coax through an adapter that connects to the output BNCs of the instruments under test.
The procedure requires alternate use of clips and BNCs, and a push of a button is much quicker than swapping leads all the time. Granted, for "normal" use those rear terminals are probably not used much.

[jsmith45]

I'm curious about the unpopulated crystal marked X2 and seen near the top at around 19:24 on the video. Any ideas what that was for, and why it would not be needed?

I'm also slightly curious about the unpopulated connector next to it. Normally I would not be curious, because it looks very plausibly to be for some form of testing purpose, but the silkscreen makes it look like it would be as fairly substancial connector socket, while test connectors are usually just cheap headers or similar.  Any speculation?

[free_electron]

MORE TEARDOWNS . that's where the fun is

[mikeselectricstuff]

I'm curious about the unpopulated crystal marked X2 and seen near the top at around 19:24 on the video. Any ideas what that was for, and why it would not be needed?

Alternate for the surface mount xtal oscillator to the left of it.

I'm also slightly curious about the unpopulated connector next to it. Normally I would not be curious, because it looks very plausibly to be for some form of testing purpose, but the silkscreen makes it look like it would be as fairly substancial connector socket, while test connectors are usually just cheap headers or similar.  Any speculation?

Another USB socket?

[Someone]

I think you were way too hard on the build quality.
Surface rust, presumably a by-product of laser or waterjet cutting, is a non-issue as long as there isn't powdery rust falling off anywhere.
Airflow path looked perfectly reasonable to get a more stable temperature - probably not essential but for a DMM, stable temperature can't hurt.
The holes spread out around the divider looked like they should give a reasonable airflow over most of the board.
I see no problem with spade connector onto a flap in the metal, as long as it's not rusty and thickness is OK, and it's arguably safer as screws can come loose.

As for caps - has anyone actually done any proper tests on lesser brands ? Just because you've never heard of them doesn't mean they're not perfectly adequate for the job.
And of course they're very easy to replace if they do eventually die, so not really a big deal, less so where they're not running in a hot environment.

Agree completely, the earthing is a well done design and Dave didnt even touch on the PCB earthing of previous products which would fail Australian compliance. Accelerated life testing is easy for capacitors and fits in easily with a project schedule so its something they easily could have done (compared to the difficulty of proving and burning in select on test voltage references).

[EEVblog]

When they do this:
It's fair game to be comparing the two, regardless of price point.
If they don't want the comparison made, they should design an original front panel.

That's true from a usability/features point of view, and is why I showed the two.
But they are very different beasts in terms of specs. So in terms of bang-per-buck based on specs, they should not be compared in that way.

[EEVblog]

One thing that obviously struck me was the similarity to the Agilent/Keysight and it's implications for the future. If Fluke can get a batch of meters stopped at customs and banned for literally "being yellow" how and why are Keysight letting a competitor (albeit a lower end competitor) get a foothold using such a blatant interface rip off?

Probably because Keysight do not have Trademarks on every aspect of the design, if any at all which is most likely.
Fluke trademarked the yellow holster, which is why they are able to defend it.

Don't get me wrong, I'm all for competition and I shed no tears for large corporations but this unit is just asking for a copyright infringement lawsuit!

Because it's not really a Copyright thing, as it's not an exact 1:1 copy.
It's more a "trade dress" issue which comes under Trademark law.

[EEVblog]

I think you were way too hard on the build quality.
Surface rust, presumably a by-product of laser or waterjet cutting, is a non-issue as long as there isn't powdery rust falling off anywhere.

But the rust is there, and that's a fact that differentiates this gear from other gear.

Airflow path looked perfectly reasonable to get a more stable temperature - probably not essential but for a DMM, stable temperature can't hurt.
The holes spread out around the divider looked like they should give a reasonable airflow over most of the board.
I see no problem with spade connector onto a flap in the metal, as long as it's not rusty and thickness is OK, and it's arguably safer as screws can come loose.

Sure, it's no doubt adequate, and that was confirmed by the thermal camera shot.
I spent half the time yapping on that the fan could likely have been designed out.

As for caps - has anyone actually done any proper tests on lesser brands ? Just because you've never heard of them doesn't mean they're not perfectly adequate for the job.
And of course they're very easy to replace if they do eventually die, so not really a big deal, less so where they're not running in a hot environment.

I always point it out because it's a potential indicator of whether or not they are concerned with price or long term build quality.
Every experienced design engineer knows if you want to use quality parts for best long term assurance, then you spec proven industry leading parts into your BOM.
You are correct in that it doesn't mean they are not "perfectly adequate for the job", which is why you won't find me screaming "don't buy this POS because of the caps they are using".
Given that capacitors are classic failure mode for products, it is very worthwhile (and expected of a reviewer) that they point them out.

It's a fact that the lesser brand do not have the same reputation as the quality brands. "Tests" in this instance come in the form of many decades of proven reliability in a brand and their production and quality processes. You can't just take a dozen caps from a cheapie manufacturer, life cycle test them, and instantly deem that brand to be top notch and on par with the others. It doesn't work like that. Reputations like that are built slowly in this business.

[WN1X]

But the rust is there, and that's a fact that differentiates this gear from other gear.

Siglent probably has a patent and/or trademark for their rust 

[EEVblog]

NOTE:
I have split thecapacitor quality discussion to it's on thread, as I think it's a worthwhile and could develop on it's own:
https://www.eevblog.com/forum/projects/capacitor-quality/

[tautech]

Following on from a discussion of caps used in Siglent equipment.....
Dave shifted it to a new thread, linked above ^


Thing is, this could but need not turn into a badcaps thread, counter productive if it did. (haha already shifted)
I've got old caps in my parts box that when I saved them they were considered "top" brands (Elna, Philips etc), but would I use them now....no way.

Have I seen or heard of any Siglent failures as a result of caps failing......NO

[VK3DRB]

Good tear down once again. PCB overlay work gets 5/10 if I were marking their work. But you get what you pay for. You never did mention if the fan can be disconnected permanently. Looks like it can.

If Agilent/Keysight and their UI had copyright or patents, they should sue the pants off Siglent for theft of intellectual property. It is not flattery, it is an insult to Keysight's design engineers and Keysight will lose market share. What is it with these Chinese manufacturers that they have to copy, rather than improve, or even invent something?

American innovation is outstanding compared to most other countries. It might have something to do with what we read in Homer Hickam's book Rocket Boys (and the great movie October Sky) which epitomises the American dream.

[nowlan]

I think comparison with similar priced units is required. Rigol DM3058 5.5 meter.

Comparing to Agilent is fun in terms of ripping off the interface. But that is one of the selling points. Now we can get the fancy graphs on a cheaper unit.

Not happy about the earthing lug. Should be a ring with shake proof, etc.

At least it doesnt have wires scraping on sharp edges like the last video.

The relay clicking during the current sense had me concerned when I saw signalpath. Does it only do this on that one screen?

Curious about fan noise, and if it is temp controlled.

[EEVblog]

If Agilent/Keysight and their UI had copyright or patents, they should sue the pants off Siglent for theft of intellectual property.

Copyright is automatic, but that very likely does not apply here, because Siglent did not do an EXACT copy. As I mentioned before, this is a "trade dress" Trademark issue.

[EEVblog]

Curious about fan noise, and if it is temp controlled.

Almost certainly not.
There would be no need to control fan speed in a constant power dissipation product like this. Unless you wanted to compensate for ambient as well (e.g. in a rack mount instrument)

[SL4P]

For the various criticisms - which are completely legitimate... this is one area where 'developing' export countries will overwhelm the 'first world'...

To make these 'knock off' product *exactly as good* as the premium brands will be entirely possible within a couple of years.  The only thing missing - which Dave pointed out - is the quality of the *project management*, and *discipline* during parts selection, and assembly QA.

Relatively easy to overcome, and may add 10% to the sell price - still well below the incumbents.

[funkyant]

When they do this:
It's fair game to be comparing the two, regardless of price point.
If they don't want the comparison made, they should design an original front panel.

That's true from a usability/features point of view, and is why I showed the two.
But they are very different beasts in terms of specs. So in terms of bang-per-buck based on specs, they should not be compared in that way.

I see your point, but to an average consumer or hobbyist, which is the target of a PSU in this price point, they may think that the products are pretty much the same just going on the look and feel. And to me this is misleading, and not good practice if brand reputation and longevity is important.

A perfect example of this is the teardown I did of a recordplayer released by a reputable brand, which cosmetically copied the industry leader, but then failed to deliver on build quality and performance.

Just reading through my Youtube comments show that a lot of people went to buy this based on the look of it, and were very surprised when they saw my teardown and comparison.

[mikeselectricstuff]

Not happy about the earthing lug. Should be a ring with shake proof, etc.

Why ?
A ring connection has more parts that could fail. As long as the thickness is correct and the surface treatment suitable, making a tab from the chassis is going to be more reliable.
 

[VK3DRB]

For the various criticisms - which are completely legitimate... this is one area where 'developing' export countries will overwhelm the 'first world'...

To make these 'knock off' product *exactly as good* as the premium brands will be entirely possible within a couple of years.  The only thing missing - which Dave pointed out - is the quality of the *project management*, and *discipline* during parts selection, and assembly QA.

Relatively easy to overcome, and may add 10% to the sell price - still well below the incumbents.

A more realistic idea is to make copying difficult. I worked on a high volume automotive instrument some years ago which was to be exported to China. The micro had no industry markings on it, reading the code out through a debugger was near impossible, and the baud rate for serial comms was not 8192 kbps, but a tight 8000 kbps. Using an oscilloscope, the crook would think the baud rate was 8192, but it had to be 8000 +/- 100 to get a response from the micro. Very sneaky. Furthermore, we used password encryption in the system. 4.3 billion possibilities and there was a 5 second purposed delay in the micro for each retry, taking up to 682 years for a brute force attack to crack it. Not a bullet proof system, but making life hard for criminals is a good cause. To my knowledge they never copied it.

Unfortunately such protection is not afforded to something like a multimeter, unless Keysight branded their chips with other numbers, or got special ASICs made that were only available to them. Even then, the People's Liberation Army may well try to steal the intellectual property through cyber hacking into Keysight's company.

The best solution is we in the West should support and reward those who created the IP in the first place and buy the genuine item, and rebuke buying "copy watch" products. In any case unless you are very poor, it is best to go for the best to go for the Keysight/Aglient/HP DMM. After all, the quality is remembered long after the price is forgotten.

[SeanB]

Spade connection is pretty reliable. Only fails when subjected to corrosion and prolonged use at high temperature, high current and vibration. Pretty much every fridge, freezer and airconditioner has them to power the motor, and there they do fail after a decade or two, but not that often in comparison to the installed base of connectors.

[SL4P]

For the various criticisms - which are completely legitimate... this is one area where 'developing' export countries will overwhelm the 'first world'...

To make these 'knock off' product *exactly as good* as the premium brands will be entirely possible within a couple of years.  The only thing missing - which Dave pointed out - is the quality of the *project management*, and *discipline* during parts selection, and assembly QA.

Relatively easy to overcome, and may add 10% to the sell price - still well below the incumbents.

:::
Unfortunately such protection is not afforded to something like a multimeter, unless Keysight branded their chips with other numbers, or got special ASICs made that were only available to them. Even then, the People's Liberation Army may well try to steal the intellectual property through cyber hacking into Keysight's company.
:::.

You may have missed my point that the issue will not be *copying* in a few years, but the OEM Chinese equipment will soon be every bit as good as the current 'western' brands.  Their own self ft ware, their own designs - everything.
It's just an inevitable fact, like Japanese products in the 60's became the go to source in the mid-70s

[fcb]

For the various criticisms - which are completely legitimate... this is one area where 'developing' export countries will overwhelm the 'first world'...

To make these 'knock off' product *exactly as good* as the premium brands will be entirely possible within a couple of years.  The only thing missing - which Dave pointed out - is the quality of the *project management*, and *discipline* during parts selection, and assembly QA.

Relatively easy to overcome, and may add 10% to the sell price - still well below the incumbents.

:::
Unfortunately such protection is not afforded to something like a multimeter, unless Keysight branded their chips with other numbers, or got special ASICs made that were only available to them. Even then, the People's Liberation Army may well try to steal the intellectual property through cyber hacking into Keysight's company.
:::.

You may have missed my point that the issue will not be *copying* in a few years, but the OEM Chinese equipment will soon be every bit as good as the current 'western' brands.  Their own self ft ware, their own designs - everything.
It's just an inevitable fact, like Japanese products in the 60's became the go to source in the mid-70s

At the low end, I think your quite right.  I have a Rigol DS1054Z (& a bunch of other scopes from HP/Agilent) - nothing can touch it for price vs. performance.  But if I wanted to spend say $5K+ on a scope I wouldn't consider anything other than Keysight/Tek and perhaps R&S (not Lecroy - I've seen far to many dead Lecroy's).

I'm looking for a new bench DMM, but probably going to spend the extra on a Keysight 34465A - need something I can trust...

[rdl]

Rust is corrosion. Under some conditions the rust inside Siglent's products may not get much worse, but in most cases it will. And one thing rust never does is "get better".

No matter what the price or quality of the item is, the fact that Siglent continues to ship product already corroding inside is disgraceful and borders on dishonesty.

It demonstrates a complete lack of respect for their customers.

[fcb]

Rust is corrosion. Under some conditions the rust inside Siglent's products may not get much worse, but in most cases it will. And one thing rust never does is "get better".

No matter what the price or quality of the item is, the fact that Siglent continues to ship product already corroding inside is disgraceful and borders on dishonesty.

It demonstrates a complete lack of respect for their customers.

I don't get how a little rust on the internal edges of their casings "borders on dishonesty" or "demonstrates a complete lack of respect for their customers"... That's like saying that they shouldn't use "Lelon" or "capXon" capacitors in certain parts of their design - can anyone point me to a proper engineering study that shows that a Lelon capacitor is better/worse than a comparable Rubycon or Nippon Chemicon part?

How else do you think Siglent manage to make this gear for such a low RRP?

[nctnico]

Rust is corrosion. Under some conditions the rust inside Siglent's products may not get much worse, but in most cases it will. And one thing rust never does is "get better".

I guess you should not look under your car if you hate rust.

[madires]

Rust is corrosion. Under some conditions the rust inside Siglent's products may not get much worse, but in most cases it will. And one thing rust never does is "get better".

No matter what the price or quality of the item is, the fact that Siglent continues to ship product already corroding inside is disgraceful and borders on dishonesty.

It demonstrates a complete lack of respect for their customers.

That rust is created by the laser cutting process, please see http://www.mmsonline.com/articles/for-laser-shops-oxidation-retaliation for example. Possibly it's no big deal, but seeing the rust on a brand new toy is very disappointing. Nobody would expect rust. It's brand new.

[SeanB]

I guess you should not look under your car if you hate rust.

the underside of a vehicle is generally the part that gets the most attention for full paint and corrosion protection. There is no metal there that is left bare, though you will find that the interior side inside the dashboard and seats often has bare metal with only a thin coat of a protective paint or zinc on it. The bottom is the part most likely to get damaged by impact with stones and sand, so is always going to have a coat and no rust when new.

[rdl]

Obviously I'm wrong, but I thought they had claimed to have fixed the rust problem?

If there was rust on the outside where anyone could see it, you can bet they'd clean it up. Instead, the rust is hiding on the inside where they obviously hope no one will notice. Their concept of quality is ridiculously bad.

There's a world of difference between a vehicle intended for operation outdoors and a piece of precision test equipment, which is what they're try to pass this off as. And there is very little rust on my vehicle anyway, probably less than what's been found on the Siglent stuff Dave has reviewed.

Personally I've already written Siglent off as hopeless and decided to not waste any more time looking at their junk, but I figured Dave's tear down would make for some decent Friday evening entertainment.

[VK3DRB]

You may have missed my point that the issue will not be *copying* in a few years, but the OEM Chinese equipment will soon be every bit as good as the current 'western' brands.  Their own self ft ware, their own designs - everything.
It's just an inevitable fact, like Japanese products in the 60's became the go to source in the mid-70s

The difference is the Japanese took western ideas and IMPROVED on them, much to the credit of an American named William Demming. Unlike China, Japan became highly respected among western countries as an innovator. China needs to revise its education system to promote innovation, and of course abolish communism.

[tautech]

Obviously I'm wrong, but I thought they had claimed to have fixed the rust problem?

Some time back they did.

It was identified as poor plating of the panel steel used by Siglent's chassis suppliers.
This AFAIK is no longer a problem.

If there was rust on the outside where anyone could see it, you can bet they'd clean it up. Instead, the rust is hiding on the inside where they obviously hope no one will notice.

http://www.astm.org/SNEWS/APRIL_2006/dallynside_apr06.html

How Metallic Coatings Protect Steel
The second shielding mechanism is zinc’s ability to galvanically protect steel. When base steel is exposed, such as at a cut edge or scratch, the steel is cathodically protected by the sacrificial corrosion of a zinc-bearing coating.

https://en.wikipedia.org/wiki/Galvanization

Galvanizing protects in two ways:
It forms a coating of corrosion-resistant zinc which prevents corrosive substances from reaching the more delicate part of the metal.
The zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.

Engineers should know this basic stuff. 

[SL4P]

You may have missed my point that the issue will not be *copying* in a few years, but the OEM Chinese equipment will soon be every bit as good as the current 'western' brands.  Their own self ft ware, their own designs - everything.
It's just an inevitable fact, like Japanese products in the 60's became the go to source in the mid-70s

The difference is the Japanese took western ideas and IMPROVED on them, much to the credit of an American named William Demming. Unlike China, ...

Have you taken a look at the number of Chinese graduates - both in China, and working overseas - that have higher tertiary qualifications from the US, Australia and others?
The next generation is coming - fast.
It's not something we have to want or agree with, it's simply rebalancing the global pool of skills and opportunity.

p.s. there's a very high likelihood that the Keysight, Tek,
lecroy gear you buy next week has a significant contribution from non-western engineers.

[Marco]

Even if they feel they have to use pre-coated steel (rather than coating after forming/cutting) couldn't they just take 10 seconds to coat the edges?

[tautech]

Even if they feel they have to use pre-coated steel (rather than coating after forming/cutting) couldn't they just take 10 seconds to coat the edges?

Tek never bothered with that for the TDS2000 series, one I've got has rusty cut edges too.

[alho]

Unless theres a usability problem all manufacturers should copy each others layout. After all its only arranging small squares on bigger squares, no great innovations to be made in this area. Extreme example would be if every calculator had different layout with only purpose being different. A resent video of Rigol gear with odd tilted buttons on left side of screen comes to mind, being different for the sake of being different.

China needs to revise its education system to promote innovation, and of course abolish communism.

Isn't calling China communistic a bit like calling Saddam Hussein democratically elected. I mean people did vote for him in elections but does that really count?

[all_repair]

You may have missed my point that the issue will not be *copying* in a few years, but the OEM Chinese equipment will soon be every bit as good as the current 'western' brands.  Their own self ft ware, their own designs - everything.
It's just an inevitable fact, like Japanese products in the 60's became the go to source in the mid-70s

The difference is the Japanese took western ideas and IMPROVED on them, much to the credit of an American named William Demming. Unlike China, Japan became highly respected among western countries as an innovator. China needs to revise its education system to promote innovation, and of course abolish communism.

You are not aware does not mean that innovative new creation from China does not exist.  This gap has been capitalised by quite a few kickstarters by reselling China new gears as their inventions.  As Dave correctly pointed out, the process to perfect small details shall take many many iterations and need times to deliver.  It is like 80/20 rule.   When these small details are ironed out, if Siglent and Rigol still exist, their ability may not be what you have wished for.   Incidentally, this is actually hard money that HP had concluded long ago compare to  selling toner and ink.

[rdl]

Engineers should know this basic stuff. 

They should. Why don't you send those links to the ones at Siglent.

It's just strange that even the cheapest of consumer electronics can be made rust free, yet that is apparently  considered too much to ask from a manufacturer that wants you to spend over $400 on a piece of test equipment.

[mikerj]

Galvanizing protects in two ways:
It forms a coating of corrosion-resistant zinc which prevents corrosive substances from reaching the more delicate part of the metal.
The zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.

Engineers should know this basic stuff. 

So why are the cut edges of the Siglent chassis visibly rusting if the galvanising is supposed to prevent this?

[Monkeh]

something on topic

i probably missed some posts in between but, the toroid does have a shorted turn? or it does not? was there any follow up detail on this?

The insulating washer was quite obvious, and the fact that the supply works properly seems to indicate there's no shorted turn.

Also, I think you're in the wrong thread.

[tautech]

Galvanizing protects in two ways:
It forms a coating of corrosion-resistant zinc which prevents corrosive substances from reaching the more delicate part of the metal.
The zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.

Engineers should know this basic stuff. 

So why are the cut edges of the Siglent chassis visibly rusting if the galvanising is supposed to prevent this?

Plated panel steel rusts on the cut edge to a thin layer but never gets worse while there is adjacent Zinc to provide sacrificial protection.

I've had decades of experience in Galvanised outdoor rural hardware that when if broken/cut/repaired the bare steel only ever gains surface rust, even in our wet NZ climate. This is not to say for many the look of a patch of rust is unsightly but while Galvanic protection is available it does not get worse. All steel rusts without some protection, panel steels are often Zinc plated as there is very little thickness to withstand the rigours of time but some thicker panel steels are even used as bare steel panels on buildings and because of their formulation they only surface rust and stay that way for a bronzed look for the building. Not my cup of tea I may say, although you don't have to paint it. 

[3roomlab]

Galvanizing protects in two ways:
It forms a coating of corrosion-resistant zinc which prevents corrosive substances from reaching the more delicate part of the metal.
The zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.

Engineers should know this basic stuff. 

So why are the cut edges of the Siglent chassis visibly rusting if the galvanising is supposed to prevent this?

Plated panel steel rusts on the cut edge to a thin layer but never gets worse while there is adjacent Zinc to provide sacrificial protection.

I've had decades of experience in Galvanised outdoor rural hardware that when if broken/cut/repaired the bare steel only ever gains surface rust, even in our wet NZ climate. This is not to say for many the look of a patch of rust is unsightly but while Galvanic protection is available it does not get worse. All steel rusts without some protection, panel steels are often Zinc plated as there is very little thickness to withstand the rigours of time but some thicker panel steels are even used as bare steel panels on buildings and because of their formulation they only surface rust and stay that way for a bronzed look for the building. Not my cup of tea I may say, although you don't have to paint it. 

iirc the sacrificial method works if there is a complete circuit iron-zinc-common_medium (like water? soil? mud?), but here the iron parts are exposed to air direct (so there is only air-steel direct, and zinc is not in the circuit). in this case i dont think zinc will perform its magic? which means if exposed to salted air, the edge will still continue to rust? no? which is why i think we see alot of those screws which were originally shiny, the rust will attack the knicked areas of screwing with it, and chew up the protection from under the coating as the oxide expand and flake off the coating. but it is such time consuming process

[tautech]

Galvanizing protects in two ways:
It forms a coating of corrosion-resistant zinc which prevents corrosive substances from reaching the more delicate part of the metal.
The zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.

Engineers should know this basic stuff. 

So why are the cut edges of the Siglent chassis visibly rusting if the galvanising is supposed to prevent this?

Plated panel steel rusts on the cut edge to a thin layer but never gets worse while there is adjacent Zinc to provide sacrificial protection.

I've had decades of experience in Galvanised outdoor rural hardware that when if broken/cut/repaired the bare steel only ever gains surface rust, even in our wet NZ climate. This is not to say for many the look of a patch of rust is unsightly but while Galvanic protection is available it does not get worse. All steel rusts without some protection, panel steels are often Zinc plated as there is very little thickness to withstand the rigours of time but some thicker panel steels are even used as bare steel panels on buildings and because of their formulation they only surface rust and stay that way for a bronzed look for the building. Not my cup of tea I may say, although you don't have to paint it. 

iirc the sacrificial method works if there is a complete circuit iron-zinc-common_medium (like water? soil? mud?), but here the iron parts are exposed to air direct (so there is only air-steel direct, and zinc is not in the circuit). in this case i dont think zinc will perform its magic? which means if exposed to salted air, the edge will still continue to rust? no? which is why i think we see alot of those screws which were originally shiny, the rust will attack the knicked areas of screwing with it, and chew up the protection from under the coating as the oxide expand and flake off the coating. but it is such time consuming process

Much more so in a dry climate and/or indoors.

[amirm]

If Agilent/Keysight and their UI had copyright or patents, they should sue the pants off Siglent for theft of intellectual property.

Copyright is automatic, but that very likely does not apply here, because Siglent did not do an EXACT copy. As I mentioned before, this is a "trade dress" Trademark issue.

This is not correct Dave.  I speak from experience having lost a lawsuit because three of our buttons matched the same functionality as our competitor.  There is case law dating back to 1970s saying that the structure of a program can be protected by the copyright.  So to the extent a key invokes a specific functionality, then that can be considered as its flow and hence protected by copyright.  This was the interpretation of the judge in our case.  It was considered "bad law" and a number of law firms wanted to repeal it on appeal.   But we had to settle and didn't get that far.

Note that our entire design and firmware was original with nothing whatsoever the same as our competitor.  Simply had the same buttons to program a timer value (one for each digit).  We had two expert witnesses attest to the same yet we still lost a case that essentially said we copied the other guys firmware.  All because the buttons were the same.

Now there may have been other case law since then (1980s) that would help defend against such a thing.  But I would not bet on it in a million years.  Our legal costs were almost $50,000 in 1980s dollars and this was a hobby company.  My advice to anyone building a device is to stay well away from any other person's interface/buttons.

[3roomlab]

If Agilent/Keysight and their UI had copyright or patents, they should sue the pants off Siglent for theft of intellectual property.

Copyright is automatic, but that very likely does not apply here, because Siglent did not do an EXACT copy. As I mentioned before, this is a "trade dress" Trademark issue.

This is not correct Dave.  I speak from experience having lost a lawsuit because three of our buttons matched the same functionality as our competitor.  There is case law dating back to 1970s saying that the structure of a program can be protected by the copyright.  So to the extent a key invokes a specific functionality, then that can be considered as its flow and hence protected by copyright.  This was the interpretation of the judge in our case.  It was considered "bad law" and a number of law firms wanted to repeal it on appeal.   But we had to settle and didn't get that far.

Note that our entire design and firmware was original with nothing whatsoever the same as our competitor.  Simply had the same buttons to program a timer value (one for each digit).  We had two expert witnesses attest to the same yet we still lost a case that essentially said we copied the other guys firmware.  All because the buttons were the same.

Now there may have been other case law since then (1980s) that would help defend against such a thing.  But I would not bet on it in a million years.  Our legal costs were almost $50,000 in 1980s dollars and this was a hobby company.  My advice to anyone building a device is to stay well away from any other person's interface/buttons.

if you read how RIGOL only succeeded to sue "whatsthecompanyname?" at 3rd try over a course of ... what 4-6 years? (there was a thread about it in amoBBS?) and for that, it was claimed as direct IP infringement. how long will Agi/KS take to get CHINA legal system to recognize SIGLENT copied some of their (Agi/KS) design?

[Kleinstein]

Before Chinese legal system will recognize that a chinese company has copied a US company design, you probyly have to wait for the US company to have Chinese owners. Even than I don't think it will be fast. They may be faster if a US company has copied a Chinese design. However US companies should not complain  - the US legal system is no better.

[mikeselectricstuff]

Before Chinese legal system will recognize that a chinese company has copied a US company design, you probyly have to wait for the US company to have Chinese owners. Even than I don't think it will be fast. They may be faster if a US company has copied a Chinese design. However US companies should not complain  - the US legal system is no better.

Simpler than that, US will simply ban imports, like Fluke did with Sparkfun's yellow multimeters

[Fungus]

Before Chinese legal system will recognize that a chinese company has copied a US company design, you probyly have to wait for the US company to have Chinese owners. Even than I don't think it will be fast. They may be faster if a US company has copied a Chinese design. However US companies should not complain  - the US legal system is no better.

Simpler than that, US will simply ban imports, like Fluke did with Sparkfun's yellow multimeters

In China they'll ban the US original that was cloned. For the same reasons.

[f4eru]

China needs to revise its education system to promote innovation

The chinese education system might be better than the Japanese, which is based on memorizing without thinking.

Unlike China, Japan became highly respected among western countries as an innovator.

China is quickly becoming the biggest innovator in tech. They have an incredible IP sharing system the west cannot match.
http://www.bunniestudios.com/blog/?cat=7

China needs to ..., and of course abolish communism.

Not the topic here. And more or less wrong anyway. China is not communist.

[f4eru]

  There is case law dating back to 1970s saying that the structure of a program can be protected by the copyright.

That's only in the US. Most other countries don't care.

[Brumby]

Indeed.

The rules for Intellectual Property (IP) vary from country to country.

For one thing - there is no such thing as a "world wide patent".  If you want to patent something globally, then you have a lot of work (and expense) to get through, with no guarantee of success.

I'm stopping there - as this topic is a massive can of worms.

[kj7e]

Its quite apparent Siglent took its "inspiration" from the 34461a.  In the end, I really dont think it will hurt Keysight in anyway.  Kind of like if Hyundai where to build a sports car that looked almost the same as a C7 Corvette for less than half the price.  Those who still want the Corvette are not going to be persuaded to buy the Hyundai even if it looked quite good and had reasonable performance.   The cheaper option will simply allow those who would not otherwise spend the money for the real deal to get in on the game.

I would greatly prefer a 34461a, but could not find any used so I ordered the SDM3055.  Not had a chance to play with it yet, the first one I received had a internal metal cover (ADC cover likely) come loose in shipping so it was sent back.  The replacement arrived yesterday but I'm out of town this week.  Really hopping the meter performs well and will last me a few years until I can find a good deal on a used 34465a.  Time will tell.

As far as overall build quality, I grew up with a room full of 1950-1970's HP gear (all I could afford as a kid).  I still have a 3440a DMM, 5245L counter and 200CD audio oscillator.  Talk about build quality, cast aluminum frames, solid engraved and etched front panels and the general spare no expense internal construction and parts selection.  The gear is 50 years old and still works!  But in 1963 the 3440a was $1400.  No one builds gear like that anymore.

[tszaboo]

Unless theres a usability problem all manufacturers should copy each others layout. After all its only arranging small squares on bigger squares, no great innovations to be made in this area. Extreme example would be if every calculator had different layout with only purpose being different. A resent video of Rigol gear with odd tilted buttons on left side of screen comes to mind, being different for the sake of being different.

China needs to revise its education system to promote innovation, and of course abolish communism.

Isn't calling China communistic a bit like calling Saddam Hussein democratically elected. I mean people did vote for him in elections but does that really count?

Same opinion here. Look at the Rigol DP800 series power supply. They did not wanted to copy, come up with something entirely new, it turned out to be horrible. I'm really fine, with copying the layout of the multimeter. I dont think there is anyone saying, that I'll buy this one, because it looks like an agilent, but it is cheaper. Or anyone mistaking it to an agilent. On the other hand, when you bought one, it is a big plus, if it is usable.