REVIEW - Owon SDS7102 - A look at the SDS series from Owon

[lemon]

My way to improve the "Noise GND" is coming to end.

After psu mods (about this decoupling way, see the message of Siri member and the rest from #928 post), it comes the time of adapter board mods. Same way, everything decoupling capacitors from Step-down converter +3.3V, converter +5.5V to converter +8.8V for LCD display back-light (see some to %959 post). The rf-loop works was helping me a lot of (from Electronics and Owon SmartDS oscilloscopes Forum).

Now the total noise threshold is btw 48-62mV without any ferrite. The noise is the same either ac or battery operation.

[TomC]

My way to improve the "Noise GND" is coming to end.

After psu mods (about this decoupling way, see the message of Siri member and the rest from #928 post), it comes the time of adapter board mods. Same way, everything decoupling capacitors from Step-down converter +3.3V, converter +5.5V to converter +8.8V for LCD display back-light (see some to %959 post). The rf-loop works was helping me a lot of (from Electronics and Owon SmartDS oscilloscopes Forum).

Now the total noise threshold is btw 48-62mV without any ferrite. The noise is the same either ac or battery operation.

Good work lemon! Thanks for all the updates. I will be soon ordering some supplies to try to reduce the GND noise without altering the circuit boards. Right now my primary candidates are ferrites designed to fit ribbon cables and ferrite based pressure sensitive EMI absorbent material.

[lemon]

Thanks TomC.
For the ribbon flat cable look those at post #966. Probably is the best for this area. Additional add a small one to the battery cable and you are OK without problems to warranty.

[mswhin63]

I got a feeling that the noise issue may have been recently resolved by OWON as my noise level is less 5mV although bit spiky it is not as bad a 50mV. I am not sure how to open my scope but as it is at an acceptable level then I don't particularity want to open it.

[lemon]

Yes, from other information that I had (version 1312XXXX),  the Owon has decrease the issue with the "noise gnd".
5mV is very low noise for fullBW, are you sure that you test it in full BW? I think that you have measured with BW limited.

Please, repeat the test with the following procedure.

Set the probe and cable as the following photo at the right side.


- Make a Calibration procedure as the manual describe.
- Compensate the probe as manual describe.
- Change switch probe to 10x.
- Do the same and with the Probe Owon Menu (10X).
- Connect probe to Probe Comp and GND wire to GND.
- Turn CH2 off.
- CH1 to DC, 50mV/Div.
- Push Trigger 50%
- Set the Acquire Mode to Peak and Length to 1M
- Set the Horizontal speed to 100us
- Set the measurement to Voltage peak to peak (Vp to Owon) and write the value.

Finally take a capture (png format) and upload the pattern of noise gnd

[mswhin63]

The Acquire length was the difference, hard to keep up with an 88 page thread. After changing the length to 1M the noise figure increased to 26mV not BW limited. I had the acquired length at 10K before and the sample method not peak.

Still comparatively better but not overly. I currently don't have anything to save onto as my lab is strewn all over the place. Have saved it internally but got a weird Pk-Pk reading of 260mV which equates to a measuring issue. So I used the cursor to measure the noise value at 26mV. mmmm

Have exams to deal with ATM so I don't have a lot of time to fiddle about.

[lemon]

26mV peak to peak, very nice noise gnd!
Can you remember me what S/N have you had (without the last numbers)?

I am afraid that the following, I don't understand! What is ATM?
 

...Have exams to deal with ATM so I don't have a lot of time to fiddle about.

[digsys]

  I am afraid that the following, I don't understand! What is ATM? 

ATM = At The Moment
You'll get used to these TLAs  :-)

[mswhin63]

Hi, ATM correct digsys, sorry lemon, I'll try not use non electro acronyms.

S/No SDS7102131XXXX.

Other than a basic scope it is turning out to be a nice scope. My level of capability would require a higher level scope money is a real restriction for me to afford even a Rigol 2000 series.

The only issue I have is the LAN feature, any time I use the LAN the scope freezes. That is really weird.

[lemon]

Thanks for the info Digsys!

1X week of 2013 is the production of your ocilloscope.
With the same production 12w2013 an other person, said at the Electronics ans Smart SDS Finland Forum that measured 126mV noise gnd without any spikes (peak to peak and with Mode Peak).

You have the best noise AFAIK (  )

I don't use the LAN capability, but if you see the post #1285 there is a list with "what Owon must to correct to the next fw". There is a reference for the LAN "The LAN interface was crippled by slow speed from the beginning. With the latest firmware patches it has been further crippled by a non-functional image transfer, and a flaky high depth memory transfer that in certain cases causes the DSO to freeze."
This list has sending to Owon (info@owon.com.hk) but there is no respond until now.

[dgmoore78@yahoo.com]

I understand that the noise issue was going to be resolved in the updated version that went into production in the beginning of June.  Can anybody confirm that this new version is in production?  Does anybody know if this updated version is available for sale yet?  I also wanted to confirm that the new version would be SDS71021323xxx or above

Thanks in advance for the info!

[lemon]

The S/N of member mswhin63 is SDS7102131XXXX.
That's meaning a date of production 1X week of 2013. As you can see the noise was very low.

It is logical, all the scopes with the date of production bigger or equal of this to have the same behaviour at the "noise gnd".

I have no other information about this.

[TomC]

I understand that the noise issue was going to be resolved in the updated version that went into production in the beginning of June.  Can anybody confirm that this new version is in production?  Does anybody know if this updated version is available for sale yet?  I also wanted to confirm that the new version would be SDS71021323xxx or above

Thanks in advance for the info!

dgmoore78@yahoo.com, Post #1195 contains the following message that I left at Owon's tech support beggining of June:
---------------------------------------------------------------------------------------------------------------
Dear Owon Tech support:

This is a follow up to my April 4, 2013 inquiry to which I did not receive a response. I bought my SDS71021246320 from Saelig in the USA on January 17, 2013. As I previously stated this is one of the units that has the "GND noise issue". This is the issue extensively discussed in the EEVblog and ForumUp forums on the internet. A DIY for modifying the PSU & adapter boards has also been posted but unfortunately it voids the Owon Warranty. It's been reported that Owon may be starting mass production of improved PSU and Adapter boards that include this modification during the month of June. I would greatly appreciate a response to the following questions:

1. Will the "GND noise" significantly decrease if these new boards are installed in my unit?

2. Will the Owon Warranty cover replacement of these boards in units affected by the "Gnd noise" issue?

3. Can I obtain these boards so I can fix my scope myself either free under the Warranty or at a discount if this is not possible?

A prompt and detailed response will be greatly appreciated.

Best regards,
---------------------------------------------------------------------------------------------------------------

Post #1199 contains the response I got from Owon and my interpretation of it's meaning:

----------------------------------------------------------------------------------------------------------------
"Thank you for purchasing OWON product.

As to GND noise, we have noticed there is noise, but it is not the one will affect your testing result, as you know, every scope has noise affect by testing environment.

We have not plan and exact date to make change for it now, because it is not quite abnormal. Unlike the ones said in the blog. 

 

Thank you for understanding. "
--------------------------------------------------------------------------------------------------------

If I understand this correctly, they are saying that:

1. They know there is noise.

2. In their opinion the noise doesn't affect testing.

3. That this noise is similar to other external sources of noise you may encounter while using the scope.

4. That making changes to correct this noise is not a priority because it is closer to normal than abnormal.

5. That either the noise they see or the influence they believe it has in the usability of the scope doesn't match what is said about it in the EEVblog.

6. That they are hoping that the customer finds this explanation acceptable.

As I stated before, I view the GND noise on my scope as just an inconvenience. So I can't argue that some of the statements made by Owon are untrue. However, I find it strange and inappropriate, that a test equipment manufacturer would justify an obvious flaw in their equipment by pointing out the existence of external similar conditions that mimic it. Similarly, a car manufacturer could justify a car that pulls slightly to the right on a straight and level road, by reminding the customer that common road conditions would require him to steer in a similar way anyway.

In the end, Owon didn't directly answer the questions regarding Warranty coverage. However, the tone of the message leaves little doubt in my mind that at least at present they don't plan to offer Warranty coverage or any kind of a discount.

Ultimately, Owon will have to live with the results of their actions. Saving a few dollars now may seem as a wise financial decision. But only time will tell the actual cost of disappointing current customers and causing prospective buyers to take pause.

--------------------------------------------------------------------------------------------------------------

If we are to believe that Owon is telling the truth, then any reports of newer scopes exhibiting lower GND noise levels is purely coincidental and doesn't guarantee that purchasing a scope manufactured after the beginning of June will give you similar results.

[dgmoore78@yahoo.com]

Thanks for the information lemon and Tom. 

I found a seller who was able to get me a unit from the June production run.  It will take me a few weeks to get it since it is being shipped directly form China.  I will let you all know how it works out.

...fingers crossed!

[lemon]

Good luck!

[rf-loop]

I have seen here some nice works, lemon etc..
-----------------------


Just for know:

Owon sell also spare parts.

If you are out of warranty and you have fail in scope (example some kind of self made damage), or even front or backside case broken (if example dropped)

Most expensive is whole mainboard.
But other parts prices without delivery (it depends...) are very reasonable priced.

Of course if you buy all parts it is of course some amount more expensive than whole new scope.. (but not very much.... )
Power supply,
adapter board
front panel board(s)
TFT module
main board
front and back cover
etc

Of course it is best to contact local seller who have contract with Owon then it may be more easy...

[Carrington]

Yes, and far as I know OWON accept bank transfers.

New PSU and DC/DC board cost ~ USD 50 (postage included). 

[TomC]

Thanks for the information lemon and Tom. 

I found a seller who was able to get me a unit from the June production run.  It will take me a few weeks to get it since it is being shipped directly form China.  I will let you all know how it works out.

...fingers crossed!

Hope it all works out for you! In any case, the scope is still a good buy for the money, and the GND noise problem, as far as I'm concerned, is not a deal breaker.

[TomC]

Yes, and far as I know OWON accept bank transfers.

New PSU and DC/DC board cost ~ USD 50 (postage included). 

That is good news! Would you mind posting how you got the price information. Thanks.

[Carrington]

Yes, and far as I know OWON accept bank transfers.

New PSU and DC/DC board cost ~ USD 50 (postage included). 

That is good news! Would you mind posting how you got the price information. Thanks.

I just ask to OWON. That's the price that I got, USD 50.
Note: Owon warranty don´t cover replacement of these boards.


About three weeks ago they have solved this gnd noise problem, told me a Owon´s employee.

[TomC]

I just ask to OWON. That's the price that I got, USD 50.
About three weeks ago they have solved this gnd noise problem, told me a Owon´s employee.

Thanks, I 've contacted Owon about purchasing these boards. We'll see what they say!

[Carrington]

I just ask to OWON. That's the price that I got, USD 50.
About three weeks ago they have solved this gnd noise problem, told me a Owon´s employee.

Thanks, I 've contacted Owon about purchasing these boards. We'll see what they say!

Good luck!

[dgmoore78@yahoo.com]

Hey guys,

Just received my new scope today from Hong Kong and wanted to give everybody an update on my "noise test".  My Manufacturing Date code is 1319 (SN#SDS71021319xxx)

Peak Detect:
Vp=54 mv
Vk: 17 mv

Average:
Vp=44
Vk=12

 

[lemon]

Very well!
The noise is low without any peaks.

The member "rf-loop" had suggested a method for this.

Procedure for measurent of Noise GND
----------------------------------------------------
Make a Calibration procedure as the notes says (look in manual).
Compensate the probe as manual described.
Change switch probe to 10x.
Do the same and the Probe Owon Menu (10X).
Connect probe to Probe Comp and GND wire to GND. Fix the cable of probe like the attachment photo.
Turn CH2 off.
CH1 to DC, 50mV/Div.
Push Trigger 50%
Set the Acquire Length to 1M and the Mode to Peak
Set the Horizontal speed to 100us
Set the measurement to Voltage peak to peak (Vp to Owon) and write the value.

[dgmoore78@yahoo.com]

Very well!
The noise is low without any peaks.

The member "rf-loop" had suggested a method for this.

Procedure for measurent of Noise GND
----------------------------------------------------
Make a Calibration procedure as the notes says (look in manual).
Compensate the probe as manual described.
Change switch probe to 10x.
Do the same and the Probe Owon Menu (10X).
Connect probe to Probe Comp and GND wire to GND. Fix the cable of probe like the attachment photo.
Turn CH2 off.
CH1 to DC, 50mV/Div.
Push Trigger 50%
Set the Acquire Length to 1M and the Mode to Peak
Set the Horizontal speed to 100us
Set the measurement to Voltage peak to peak (Vp to Owon) and write the value.

I updated my test process with your suggestion. 
Vp=34mV

Let me know if you would like me to try anything else.