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

[lemon]

I bought SDS7102 few weeks ago and my MATH button is light blue. I saw pictures on the internet and the MATH button is white. Is that sign of new version, i can see rf-loops sds7102 has light blue button too. BTW rf-loop very nice job  .

Yes, probably you have right. My that is a middle of 2012 model has a white FFT button.

[akis]

I received today the replacement adapter and PSU from Owon in China. I have received:

1) adapter board v3.0 dated 2011.11.14
2) adapter board v3.2 dated 2012.07.24
3) PSU board , no version on it, however it is slightly different to the one I have, for one it does not have a hole and a TO-220 transistor through it.
4) No ferrite! The lady from Owon said that this ferrite is attached to the LCD and so she did not send it to me. Whatever that means!

During the tests I have seen the greatest noise when the looped probe cable is near the bottom of the LCD. Does that mean that the LCD emits more noise than the adapter and the PSU together?

OK, I am changing the boards over now and will take some pictures if there are any good results.

[AndrejaKo]

4) No ferrite! The lady from Owon said that this ferrite is attached to the LCD and so she did not send it to me. Whatever that means!

If you look carefully at the pictures of new LCD screens, you'll see that it is in fact true. The ferrite is glued to the metal case of the LCD/Z-plate assembly and the flat flex cable is run through it. Still that's not a reason not to send you the ferrite. You can easily fix it in place yourself or use the battery holder to keep it in place. That's what I did with my ferrite.

[bob808]

I talked to the seller of my Owon sds6062v and he managed to talk to Owon factory and order a new batch of 6062 units. He specifically asked for newer version something like > 1330 production date. In a couple of weeks I should get mine and I will also post the results of the noise test. If I won't loose my warranty on it I will open it up and post some pictures of the psu/adapter board as I didn't see any from this model. Should help anyone who is considering getting the little brother of 7102
Is there a warranty void sticker on these units?

[akis]

OK, I present here a picture "before" and two "after". One picture was taken with the probe cable tucked under the screen - this is the worst interference position - also you can loop the probe cable around the Owon for similar "bad" results.

Maybe the missing ferrite might help, but as it is a flat shape, has anyone got a part number I can get it from somewhere?

[TomC]

Is there a warranty void sticker on these units?

Not on my unit. Haven't heard of anybody else finding one on their units.

[TomC]

OK, I present here a picture "before" and two "after". One picture was taken with the probe cable tucked under the screen - this is the worst interference position - also you can loop the probe cable around the Owon for similar "bad" results.

Maybe the missing ferrite might help, but as it is a flat shape, has anyone got a part number I can get it from somewhere?

The ferrite on the TFT cable should help some.  I believe Lemon has a part number from Farnell, he'll give it to you when he comes online. What I also do to limit the antenna effect of the probe cables, which is the main reason you see this increased noise when the cable is close to the TFT panel, is ferrites on the probe cable itself. One near the BNC, and one near the probe itself. I use the type intended for power cables, that way I can loop the cable around the ferrites for double the inductance.

[lemon]

This ferrite absorbs about 10-15mV from that I have seen.

Here is the link for the appropriate flat ferrite
http://export.farnell.com/jsp/search/productdetail.jsp?SKU=3538369

If it doesn't open, here is the description:
Code=3538369
KE KITAGAWA - FPC-31-12K
    FERRITE CORE, FLAT CABLE, 26MM
    Impedance @ 100MHz: 66ohm
    SVHC: No SVHC (19-Dec-2012)
    External Depth: 12mm
    External Length / Height: 5mm
    External Width: 31mm
    Ferrite Case Style: Flat Core
    Impedance @ 25MHz Typ: 26ohm
    Series: FPC

Are you sure that testing the scope as we referred?
https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg255469/#msg255469

[AndrejaKo]

OK, I present here a picture "before" and two "after". One picture was taken with the probe cable tucked under the screen - this is the worst interference position - also you can loop the probe cable around the Owon for similar "bad" results.

Maybe the missing ferrite might help, but as it is a flat shape, has anyone got a part number I can get it from somewhere?

Wow! That's quite significant! How much did you pay for the new adapter board and PSU? I'm thinking of starting to save up for them, if I don't manage to fix my unit by myself.

[akis]

I was charged $60 (US dollars), $10 for the parts and $50 for the shipping. The $50 for the shipping is so high to disguise the real price and try to avoid import duty.

I think it has made quite a lot of change and is well worth it. Yes the LCD screen also makes a lot of noise, but if you keep the probe cable directly away from the scope, at 90 degrees angle, and for at least one foot (30 cm) distance, then there is absolutely no noise.

I am not sure if the ferrite would improve matters in that configuration?

[Carrington]

I received today the replacement adapter and PSU from Owon in China. I have received:

1) adapter board v3.0 dated 2011.11.14
2) adapter board v3.2 dated 2012.07.24
3) PSU board , no version on it, however it is slightly different to the one I have, for one it does not have a hole and a TO-220 transistor through it.
4) No ferrite! The lady from Owon said that this ferrite is attached to the LCD and so she did not send it to me. Whatever that means!

During the tests I have seen the greatest noise when the looped probe cable is near the bottom of the LCD. Does that mean that the LCD emits more noise than the adapter and the PSU together?

OK, I am changing the boards over now and will take some pictures if there are any good results.

- Oh men, adapter board v3.2.  akis please converts it to v3.3, just add a capacitor.
- No ferrite! 

Hey Owon... Fail!

I am not sure if the ferrite would improve matters in that configuration?

Is not a question of believing or not, that ferrite reduce noise.
Another link:
http://www.ebay.es/itm/190837205693

[Carrington]

This should be covered by the warranty:


If something is right I support it, but if something is wrong I will not be in silent.

[bob808]

You guys should be rewarded by Owon for the work you are doing to improve their product!
I don't know if I would put in the time and stress for such a thing. And this is not even for modding, upgrading the product, but to get it to function like it was designed to...
Granted you did a very good job for the owners of the defective (is it ok to call it that way?) units. But I guess that I wouldn't struggle so much with the problem, I would just wait it out and get the replacement parts.
Does anyone know the details of the company? Like how many employees and how many units produced, and the history of the company?

[Carrington]

Does anyone know the details of the company? Like how many employees and how many units produced, and the history of the company?

No idea, I only know what it says here:
http://www.owon.com.hk/about.asp?InID=66

[akis]

I received today the replacement adapter and PSU from Owon in China. I have received:

1) adapter board v3.0 dated 2011.11.14
2) adapter board v3.2 dated 2012.07.24
3) PSU board , no version on it, however it is slightly different to the one I have, for one it does not have a hole and a TO-220 transistor through it.
4) No ferrite! The lady from Owon said that this ferrite is attached to the LCD and so she did not send it to me. Whatever that means!

During the tests I have seen the greatest noise when the looped probe cable is near the bottom of the LCD. Does that mean that the LCD emits more noise than the adapter and the PSU together?

OK, I am changing the boards over now and will take some pictures if there are any good results.

- Oh men, adapter board v3.2.  akis please converts it to v3.3, just add a capacitor.
- No ferrite! 

Hey Owon... Fail!

I am not sure if the ferrite would improve matters in that configuration?

Is not a question of believing or not, that ferrite reduce noise.
Another link:
http://www.ebay.es/itm/190837205693

If this ferrite is the genuine Wurth item, as shown here http://uk.farnell.com/wurth-elektronik/7427228/ferrite-core-flat-cable-34mm/dp/1890713?Ntt=7427228
then I am surprised he sells them for a fraction of the price we pay for them in the UK....

What capacitor do I need on the v3.2 to make it v3.3 ?

[AndrejaKo]

What capacitor do I need on the v3.2 to make it v3.3 ?

Take a look at Carrington's post with a photo in it. There is a single SMD capacitor circled in red. You need to install that capacitor. It goes between legs of an electrolytic capacitor that's above it, if I remember correctly. The capacitor should be 1 nF.

[akis]

Ah I missed that photo. I will open the scope again tomorrow now. By the way, the new PSU had the power on off switch 2-3 mm to the right, and the button does not fit anymore! So I had to break the plastic tabs on the button to make it fit

[TomC]

I was charged $60 (US dollars), $10 for the parts and $50 for the shipping. The $50 for the shipping is so high to disguise the real price and try to avoid import duty.

I think it has made quite a lot of change and is well worth it. Yes the LCD screen also makes a lot of noise, but if you keep the probe cable directly away from the scope, at 90 degrees angle, and for at least one foot (30 cm) distance, then there is absolutely no noise.

I am not sure if the ferrite would improve matters in that configuration?

That configuration is avoiding the near field of the TFT panel, which results in less EMI picked up by the probe cable, so you see less noise. However, keep in mind that this strong field is still present, and although it isn't impacting the probe cables, there are other nearby components, such as the Z-plate, that are affected by this field. Some of this effect results in conductive common mode noise, which you see as GND noise when it's converted to differential mode noise by the long ground lead. Installing the flat ferrite on the TFT flat cable reduces the field, so you have dual benefits, less radiated EMI, and less conductive common mode noise.

Also keep in mind that the probe cables are susceptible to EMI from any external source, not just the TFT panel, even the DUT may be a strong source, for example an SMPS. This is why I use ferrites on the probe cables themselves.

[TomC]

Ah I missed that photo. I will open the scope again tomorrow now. By the way, the new PSU had the power on off switch 2-3 mm to the right, and the button does not fit anymore! So I had to break the plastic tabs on the button to make it fit

If Owon didn't provide you with separate 1000pF SMD capacitors, it's possible that the capacitor was installed at the factory on the 3.2 board that they sent you. This capacitor is the only difference between version 3.2 and version 3.3. When I received my new PSU, Owon  included several 1000pF capacitors so that I could modify my 3.2 board myself. However, according to some sources, Owon has been refurbishing existing 3.2 boards to 3.3 by adding this capacitor.

[Carrington]

If this ferrite is the genuine Wurth item, as shown here http://uk.farnell.com/wurth-elektronik/7427228/ferrite-core-flat-cable-34mm/dp/1890713?Ntt=7427228
then I am surprised he sells them for a fraction of the price we pay for them in the UK....

That ferrite is even better, watch their price here:
http://www.digikey.com/product-search/en?x=11&y=17&lang=en&site=us&KeyWords=7427228

That configuration is avoiding the near field of the TFT panel, which results in less EMI picked up by the probe cable, so you see less noise. However, keep in mind that this strong field is still present, and although it isn't impacting the probe cables, there are other nearby components, such as the Z-plate, that are affected by this field. Some of this effect results in conductive common mode noise, which you see as GND noise when it's converted to differential mode noise by the long ground lead. Installing the flat ferrite on the TFT flat cable reduces the filed, so you have dual benefits, less radiated EMI, and less conductive common mode noise.

Also keep in mind that the probe cables are susceptible to EMI from any external source, not just the TFT panel, even the DUT may be a strong source, for example an SMPS. This is why I use ferrites on the probe cables themselves.

Explain this more clear is impossible. 

[tinhead]

Your observations have true base and the Vpp or Vrms will be the best for comparative results, but here we have the same methodology, the same position, the same time, the same probe, the same vertical resolution (50mV) the same or very closed horizontal time (400/500usec) and the closer memory buffer 1-2M).

Additional from what I see there is stable optical depth of camera.
I think that they are comparable.

and all that didn't matter when you do visual compare because of different display size, resolution, pixel per DIV, DIV per full ADC scale and finally dot size. In case of Owon and Hantek the resolution, size and DIV per ful ADC are different, but luckily Owon is having exact the same display type(tech. type)/manufacturer, so the dot size is the same so one can take screenshot from Hantek and 1:1 paste on Owon screenshot to compare (where of course one need to know that Hantek is doing as well 10DIV vertical, but visible are only 4.2 DIV where Owon is doing 10DIV and visible 10DIV). Siglent can't be compared to them as there are major differences.

You need to know as well that the way how the waveform is being displayed matter as well, this is where it make sense for visual compare to set intensity on full. The horizontal resolution (or actually visible dots per div and the way how they will get displayed) matter as well, there is difference between DSOs displaying only some peak dots or some amount of dots or all dots.

Anyway, let's compare measured values ...

Mine after all modifications to this test with the BNC Shorting Cap has 12-16mV (10X) on CH1 and 14-18mV on CH2.

... from stock Hantek DSO5102BMV (50mV/DIV, 80us/DIV, 2Mpoint depth, trigger on peak to catch all spikes).
CH1 does have some more noise injected from the display, without display the level is the same as on CH2.






Question1: did you measured in peak detect trigger mode?
Question2: i assume the Vp displayed on your picture is in real Vpp and not real Vp, isn't?

[lemon]

Tinhead, now I understand you better.
The Owon Vp measurement is a real Vp-p measurement with a chinglish marking!

My measurements with bnc shorted isn't a typical SDS7102 measurement becouse mine scope was a bad ground noise unit and I have a lot of mods about this.
Anyway this measurement was with 50mV/div, 100us/div, Probe 10X fullBW, Peak measurement, 1M memory.
Here one measurement with 10M memory set (the SDS7102 jump to 10M after 1M), here the range of noise is 10-12mVp-p.

At the last yours mesurements as the wave demonstrated, they seem like the Average measurement of SDS7102. Here another sample with this average measuement (the average was set to 4) but I don't think so that is the right measurement for the comparison, simple are identical as waveform together.

[tinhead]

At the last yours mesurements as the wave demonstrated, they seem like the Average measurement of SDS7102. Here another sample with this average measuement (the average was set to 4) but I don't think so that is the right measurement for the comparison

well, my pictures only looks like "avg", but they made in peak detect mode. This is due how Hantek is displaying the datapoints on display and how many of the real datapoints are displayed at once (in vectors mode it can display up to 20000 point per one DIV, which is 500 datapoints per display pixel. In Dots mode even up to 40000 points per one DIV, which is 1000 datapoints per display pixel). I can't tell you how Owon is doing this, for me it looks like "skip on similar", which speed up drawing (but it costs processing time), but as Owon is not DPO-like made this is probably the only way to go. But maybe i'm wrong, maybe Owon is displaying only smaller amout of datapoints per DIV (that could explain as well the look of the waveform on Owon).  Hantek don't need to calculate anything, the data is already in buffer (and already written into that buffer multiple times during sampling), so it have to draw it only.
 

[lemon]

I don't know how this really works but I quote another peak capture of other member with more mVp-p. Here is more clearly how the SDS7102 presents the peak measurement.

[Carrington]

Hi tinhead!
I just can tell you that I had to enlarge/reduce each image to match the volt/div scale.
No idea about how owon SDS processes the data to be displayed. I don't know if rf-loop knows how.