EEVblog #829 - Siglent SDM3055 Bench Multimeter Teardown

[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.