Siglent SDS1202X-E compensation issue (and other manufacturers ?)

[Gandalf_Sr]

If you're replying to me, I was being sarcastic.  Difficult for such sentiment to come over on a forum.

[tautech]

Just wondering because although I enjoy your analysis on equipment, I only see your focus on the Siglent line and your the only one who tolls the Siglent position.  In fact checking the few hundred posts you made in the past involves Siglent. 

You need check further back. IIRC ~#1100-1200 were mention of many brands have been studied and appraised.

Much, much experience in EE. 

Received B.B. sn# from MegaDepot, was indeed dropshiped from SIGLENT.

[N0NB]

Just for the record, here are my screenshots of both channels of my replacement BB unit.

Looking good.

[besauk]

My amazon ordered SDS1202 channel 2 vertical knob seized up within the first few turns.  Very disturbing that their component quality is so bad.  Certainly didn't help that it had the compensation issue as well.   Needless to say, it was returned and one-starred.

[N0NB]

Looking at the Amazon reviews, it seems that as the compensation issue has been reviewed at length, there are a few curious four/five star reviews that are very short and from "Amazon Customer".  Even more curious is that some replies to critical reviews are also from "Amazon Customer" followed by "Manufacturer", presumably Siglent USA.

I just find this 

[besauk]

More and more the reviews on Amazon are turning into nothing more than bogus postings from the store owner. Not sure there is a practical way to police it at their scale.

[EEhopeful.]

 Wow, I was considering a Siglent. I was even considering going out of my way and mortgage the dog and the cat to get maybe the 1204 that is almost 800, but this is too bad. I found this also:

https://www.eevblog.com/forum/testgear/siglent-they-filed-a-'wrongful-trademark-claim'/

  Then I went to ebay and see they are selling the BA series with the defect as "new" in at least one ebay auction, so I guess this is the company getting rid of them with unsuspecting buyers.

https://www.ebay.com/itm/SIGLENT-SDS1202X-E-Super-Phosphor-Oscilloscope-SPO-200-MHz-1-GSa-s-14-Mpts/332580759598?hash=item4d6f5ba82e:g:V4EAAOSwTOtaoopK

  And then I read this thread.

 How can I trust them to help me with warranty later if they already have shown all these problems with customers?? It seems that once they have your money on their pocket they could care less. What will happen when new problems are found that have not been found yet??
 
  Now I see people here bashing the Hanteks, and Owon, and even some Rigols, but then again, Siglent is kind of more expensive for the same, claiming to have a better product but it seems that in any of these brands ,what I will be chosing is what type of bug I want. I guess that if I have to chose bugs between bugs, I will just chose the cheapest one of them that fulfill my application, if the bugs have to be taken care of by myself or worked around anyone. Now that Micsig 4 channel tablet is looking more and more appealing every day. So, it is either expend big dollars for Tek or Keysight or have to deal with these bugs???

[tautech]

I have a PM from zero poster and new member iMaks-RS.

Welcome.


To iMaks-RS and readers from worldwide that wish to remedy the compensation issue in SDS1202X-E with the correct caps:
My best advice is to contact the distributor in your country and then if needed the Siglent branch in your region.
Their contact particulars and emails are in the Contact Us in the official Siglent websites:
http://www.siglent.com/ENs/lxwms.aspx?id=1337

State the SN# of your unit, seller and buy date in communications please.
Please report troubles with sourcing caps from Siglent or their dealers here and we maybe can use our contacts to help.

[iMaks-RS]

But the fact is that I already wrote two letters in support of Siglent and letters to the seller - his store on the Aliexpress site is no longer working ..

[tautech]

But the fact is that I already wrote two letters in support of Siglent ........

To whom in Siglent ? Hamburg ?
info-eu@siglent.com ?

[Gandalf_Sr]

Rob,

Does this mean that US buyers of the SDS1202X-E who find they have a scope that suffers from the compensation issue will now be able to return their scopes for a fee repair or is it only in Europe?

After 3 appeals to Siglent America they did agree to take mine back for a refund which I now have received.  I suppose I could have gone out and bought a replacement SDS1202X-E but many people here were reporting that they were still receiving bad scopes so I bought a Rigol DS1054Z instead.

You reap what you sow.

[tautech]

Rob,

Does this mean that US buyers of the SDS1202X-E who find they have a scope that suffers from the compensation issue will now be able to return their scopes for a fee repair or is it only in Europe?

Ted
AFAIK Siglent worldwide only supply caps on request for owners to do their own 'compensation issue' repairs.

After 3 appeals to Siglent America they did agree to take mine back for a refund which I now have received.  I suppose I could have gone out and bought a replacement SDS1202X-E but many people here were reporting that they were still receiving bad scopes so I bought a Rigol DS1054Z instead.

You reap what you sow.

Yes......but sourced from a local supplier you may have had a totally different experience !

[Gandalf_Sr]

Rob, My original purchase was from Saelig, the official Siglent distributor for the USA I believe.

[nctnico]

Yes......but sourced from a local supplier you may have had a totally different experience !

Which is exactly the problem!

[Gandalf_Sr]

Yes......but sourced from a local supplier you may have had a totally different experience !

Which is exactly the problem!

I'm confused, are you guys saying that I should have bought from a local Mom n Pop store?  AFAIK, there isn't one here in SE Michigan.  If that's not what you meant, then what?  Like I said, I bought from a (if not the) Siglent distributor for the USA.

[ian.ameline]

Just a quick one, is the serial number for this series also displayed internally on the system information screen ?.

Yes.
Serial number is:
- product label outside of the factory carton. (every seller can see this label without opening carton. Also factory shipping
  carton what include 4pcs scopes have every individual scope label outside of this carton.
- serial number label bacside oscilloscope.
- oscilloscope utility - info display (FW version, FPGA version, HW version, serial number, boot counter
- printed in factory calibration certificate

I returned 3 units to amazon.ca, and none of those three had the serial number on the outside of the box. I was crystal clear with Amazon that I wanted a BB serial unit, and each time they promised a BB serial number, and each time they shipped a BA serial number. I confirmed the compensation issue on each unit (hey -- maybe it had been repaired) before sending it back.

-- Ian.

[nctnico]

Yes......but sourced from a local supplier you may have had a totally different experience !

Which is exactly the problem!

I'm confused, are you guys saying that I should have bought from a local Mom n Pop store?  AFAIK, there isn't one here in SE Michigan.  If that's not what you meant, then what?  Like I said, I bought from a (if not the) Siglent distributor for the USA.

You can go both ways with this. First of all IMO Siglent should be in the lead on the customer service so that every customer gets the same level of service. This shouldn't depend on the willingness or unwillingness of the seller. However it seems in this case Siglent is unwilling to fix the problem for their customers so a supplier which goes above & beyond is a good place to buy from. OTOH that also means that such a supplier is more expensive to buy from (tricky when selling low cost items) or more likely to go out of business if they have to deal with & pay for several of these kind of incidents.

[tautech]

Yes......but sourced from a local supplier you may have had a totally different experience !

Which is exactly the problem!

I'm confused, are you guys saying that I should have bought from a local Mom n Pop store?  AFAIK, there isn't one here in SE Michigan.  If that's not what you meant, then what?  Like I said, I bought from a (if not the) Siglent distributor for the USA.

Saelig are just one from a list of US nationwide distributors/resellers and are most active here and offer EEVblog member discounts.
https://www.siglentamerica.com/how-to-buy/
Would they have/offer a service center, sorry I wouldn't know.

Now check the interactive map ^.
Lower down the chain at mom n pop (regional) level where they are 'authorized' Siglent resellers too, where real local support can be offered but this again depends on how many other brands they handle. Marketing is not a perfect science but neither is buying however for me it's quite surprising how many customers now ask what would happen if 'service' was required. I offer a full Siglent service center for my customers.

[Diabolo]

Hello,

Does the problem of compensation have a real impact on measurement accuracy? I did not check, alas.
Does this problem put the 1202X-E out of the characteristics announced by the manufacturer Siglent forcing it to correct BA units?
This is the question to ask.

Siglent Europe provided me with 4pf capacitors and I installed them myself.

I do not defend Siglent who could install these capacitors 4pf from production on its production lines.


Diabolo

[tautech]

Hello,

Does the problem of compensation have a real impact on measurement accuracy? I did not check, alas.

No.
It only effects 10x probe compensation when 1.2V/div is stepped to 1.22V+/div and the the probe needs be re-compensated.

Does this problem put the 1202X-E out of the characteristics announced by the manufacturer Siglent forcing it to correct BA units?
This is the question to ask.

They say it doesn't. 

Siglent Europe provided me with 4pf capacitors and I installed them myself.

I do not defend Siglent who could install these capacitors 4pf from production on its production lines.

They are installed since IIRC late September 2017 production.

[chipss]

 

[tautech]

 

Exactly !
We dealers must live with it too ! 

[Performa01]

Does the problem of compensation have a real impact on measurement accuracy? I did not check, alas.
Does this problem put the 1202X-E out of the characteristics announced by the manufacturer Siglent forcing it to correct BA units?
This is the question to ask.

I have measured the effect up to 50MHz soon after the probe compensation issue had been discovered some 5 months ago.

I have never published my data because in actual fact I did not want to jump into that discussion and also was curious if anyone else would make measurements in order to quantify the error. Well, I did not see this happen and to the best of my knowledge you’re the first who wants to know.

So here’s my old data.

The first graph shows the frequency response in dB for 1.2V/div and 1.22V/div with the PP215 probe.
The second graph shows the relative error between the two vertical gain settings in percent.


SDS1202X-E Probe Compensation 50MHz


SDS1202X-E Probe Compensation Error 50MHz

[Gandalf_Sr]

Hello,

Does the problem of compensation have a real impact on measurement accuracy? I did not check, alas.

No.
It only effects 10x probe compensation when 1.2V/div is stepped to 1.22V+/div and the the probe needs be re-compensated.

Er, sorry Rob but the answer should be YES....

Try this usage scenario....
1. The user has their probe set to x10 and vertical gain set to 1.2V/div or under, and then performs probe compensation on the built in square wave.
2. User then samples a waveform that goes off scale so they change to 1.22V/div or higher - there will be no warnings but the probe compensation will be wrong and the displayed waveform will be inaccurate.

Despite the fact that this is the only scope I'm aware of that does not maintain probe compensation when changing vertical gain, Siglent America claims that it is in specification; specifically they said in an email to me...

We are familiar with the probe compensation issue. All of the SDS1000X-E products are in specification. There is no specification for “probe compensation flatness” between ranges.

Siglent sent me capacitors but warned that I may invalidate my warranty by fitting them - I asked them to change the caps for me - they refused but eventually took my scope back and gave me a refund.

[tautech]

Hello,

Does the problem of compensation have a real impact on measurement accuracy? I did not check, alas.

No.
It only effects 10x probe compensation when 1.2V/div is stepped to 1.22V+/div and the the probe needs be re-compensated.

Er, sorry Rob but the answer should be YES....

Bold above added.
Ted, what is the specified vertical accuracy of most DSO's ? A = +3% or 4% under 2mV/div for SDS1202X-E.

Apply accuracy spec to Performa01's charts and YES for higher frequency the measurements fall outside accuracy spec.
Then I ask when have you needed +3% accuracy beyond 20 MHz ? 

Because we now know of the '10x probe compensation issue' users that choose to use the SDS1202X-E over a wide input range and not re-compensate when switching 1-2V/div will encounter this error.

What Performa01's charts don't show is if there's more than 3% error in amplitude at more than 1.22V/div with a properly compensated probe.