EEVblog #829 - Siglent SDM3055 Bench Multimeter Teardown

[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.