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

[Carrington]

nothing against what you say - it depends on the way the ground distribution is done.

Yes, the location of each component is critical.

Another thing that must have been designed/decided by a dev engineer who rather should be kept away in an assylum for mental cases.

Poor man, I prefer to think that he did not know what he was doing.

And of course I noticed already the noise radiated from the display but there is no way to say anything defenitely about that as long as these many connecting lines between Main PCB and display all running along on the I/F PCB in close vacinity under 4 of these little switchers. This I/F PCB acts as a perfect coupling device to make sure that all spikes are properly distributed over the entire machine.

Do you mean that are coupled with the DC/DC EMI? Right?

You see the display itself works at a relatively low voltage level signalwise, haven't checked that yet - perhaps around 3V whereas the switchers work from 8.4V and some amps are flowing.

So what would you guess makes more noise, a bunch of low current / low voltage signals or high current square waves at up to 8.4V.

Sure, but please, don't underestimate.

And should the radiation going out from the front of the dislay be too much for you you get yourelf one of this conducting but transparent microfabrics that Tek offered as an option for all of its scopes for environments that are highly sensitive to noise radiation. You know, a normal CRT radiates as well out of the screen a little...

That has been also taken into account earlier in this post, not cheap.

I think we can handle all of this.

Hum... I'm not so sure, I can assure you that that is not easy.

And after we have designed a small pcb for all the little switcher beasts and put them inside of a small tin box that will be screwed through isolated posts above the I/F PCB with no noise going outside of this box and the outputs connected with if you want shielded cables to where the voltages should really go I'm sure we have that thing cured.

Hopefully!
I already got rid of this problem. I sold mine to a vehicle repair workshops, with new boards (Owon original improved versions).

And, I tell you if this spreads around the price for this machines will fall and whoever feels like may offer a kit with all inside what we did (will not be me for sure will be off to new shores then) to convert this bastard to a decent device.

You forgot the software and firmware. Among other things...

Just search ebay for this owons as I did recently. Countless offers came up. Piles of this machines must be out waiting for uninformed buyers. Do you know what I means....?

Sure, I know...

The marks on the chips in my machine are:
upper one: OBT   24J     PDVH
lower one: 1780     TB51

See attachments. 

[TomC]

Hi Tomc,

I' sorry but I think that you want to qualify a 'deplorable state of affairs' (got it from the Dictionary) and what the heck should that help as we already know what's it's cause.

It's like counting the red spots after somebody got the measels instead of giving the right medicine.

You qualify and count red spots if you want to optimize a thing not when you have a basic, well known and documented problem.

At 100MHz a short piece of wire acts already like a coil. So what does it help using probes to qualify the prob here. It might help to find out that there is a prob but thats it.

What you explaind is absolutely right - common mode / differential mode - but is again just a refined description of the problem.

You know a machine radiating HF is like a transmitter. you have antennas, traps, ample return pathes, stray capacitances/inductivities and whatever. It will act differently if you move it from a desk made out of dry plastic to a desk made out of wood that stood before outside in the rain.

Radiation return path takes place through the mains cord but also through the electrical/magnetical fields. All of this has absolutely chaotic nature here!

If you do not want a machine to act as a transmitter kill or shield the source of the signal that makes this machine act like a transmitter not qualify how good or bad it acts as a transmitter.

Concentrate on what has to be done to make the thing work fine.

Sorry if somehow I managed to push your buttons! It wasn't my intention, just trying to explain what I see the best way I can!

I'm just going to give you a sample of what I'm talking about using pictures and let you be the judge! The first two pictures were captured using the ground noise test setup previously described. The next two pictures were taken by scoping the output of an RF generator set to 30MHz 35mVpp. Beyond that frequency I don't recommend using the 6" ground lead provided by Owon because the tank circuit formed by its inductance and the probe's input capacitance starts to affect the amplitude of the signal. The last picture was taken by scoping the output of the RF generator set to 92MHz 280mVpp.

#1 - The noise exhibited by my SDS7102 as it was received from the factory, no modifications.

#2 - The noise as it appears today, with the original PSU with two modifications, a hand wound toroid and a belly strap. There is also a ferrite on the
        ribbon cable, and the probe cables are also equipped with ferrites.

#3 & #4 - Illustrates the scope's performance when viewing low level signals, #3 with the 6" ground lead, and #4 with the spring ground clip. Note
                that the amplitude on #3 is a little higher because at this frequency the tank circuit starts to affect it. I don't have equivalent pictures from
                when the scope was unmodified, but I remember that it was impossible to even get a stable trigger due to the noise.

#5 - Illustrates the difference in signal amplitude at the tank's resonant frequency. CH1 is connected to the RF generator via the spring ground clip,
       Ch2 via the 6" ground lead.

Personally, I'm satisfied with these results. Of course they are not perfect, there is still a little ground noise, but it no longer hinders my ability to use the scope to view low level signals when I choose to use the 6" ground lead.

I think it's commendable that you are trying to get rid of all the noise, I don't know if it's possible, but I sure would like to see how far you get. So good luck with it.

By the way, the LCD panel is large source of radiated noise, but it's only a problem if you get the probe cables close to it. In my case, with the probe cables equipped with ferrites this effect is mitigated quite a bit.

[Carrington]

Hi TomC!

Personally, I'm satisfied with these results. Of course they are not perfect, there is still a little ground noise, but it no longer hinders my ability to use the scope to view low level signals when I choose to use the 6" ground lead.

This result is more than acceptable.
In addition, how you get rid of all the noise sources that don't come from the oscilloscope?

By the way, the LCD panel is large source of radiated noise, but it's only a problem if you get the probe cables close to it.

Quite so!

[TomC]

In addition, how you get rid of all the noise sources that don't come from the oscilloscope?

Hi Carrington,

Glad to see you active on this thread again!

I didn't really completely get rid of outside noise sources, but quite a bit of it is mitigated by the ferrites on the scope probe's cables.  I keep them there permanently and even in the vicinity of my computers or laptop the noise pickup is small compared to no ferrites. However, for the capture of Noise Today, the scope wasn't too close to other equipment. Otherwise the noise level may range a little higher but usually under 30mVpp.

[Sarasir]

Hi everybody,

first, thanks a lot for the sheets. will check them later as I'm busy now.

But briefly,

TomC,
I respect you findings and results. I just have to confess that it makes me a bit crazy reading things like above from you and at the same time knowing what fine engineer you are by having read your paper.

But I know often in life you have no other choice than to look for good compromise out of various reasons. And you have family and I respect that even more!!!

To tell you the truth, I'm an idealistic maniac, my life is ruled by finding the truth and success through it. Got divorced - of course love women - but if I had do decide between a new challenge and a woman I go for the challenge (after a while). Didn't care for my son as I preferred to went on tour with my band as a musician, Worked for Tek and became a top troubleshooter, went away produced and still produce LPs/CDs, compose, develope and repair electronics, had a time when I was programming, even was a dope dealer for a while, and had the best stuff and excellent high class customers (25 years ago).
But also meditate since 40 years and practise Tai-Chi and study buddistic literature.

(don't know if I should post that at all)

Bought my first scope 45 years ago - a Hameg I still use for monitoring the outputs of my self designed millivoltmeters for audio tests. A scope is an extension of my brain and it has to be as perfect as possible.

So once more: YOU DO NOT DECIDE THE LENGTH OF THE GROUND LEAD YOU USE ON YOUR PROBE ACCORDING TO THE NEEDS OF YOUR SCOPE BUT IN ACCORDANCE TO WHAT MEASUREMENT YOU HAVE TO TAKE!

If you can live with it no problem for me, but in everydays work you will have to face the limitations sooner or later. And in a serious technical discussion it's just not very helpfull.

As to the argument that the display supplies already have been removed I can only repeat myself in a way and say, naive, because only removing/shielding this or that switcher is not enough. All of them have to be removed and shielded and filtered, no way around.

And finally for now, yes of course, just keep the probe away from the display then it's radiation frontwise should be no problem.

Thanks a lot for accepting.

[TomC]

So once more: YOU DO NOT DECIDE THE LENGTH OF THE GROUND LEAD YOU USE ON YOUR PROBE ACCORDING TO THE NEEDS OF YOUR SCOPE BUT IN ACCORDANCE TO WHAT MEASUREMENT YOU HAVE TO TAKE!

If you can live with it no problem for me, but in everydays work you will have to face the limitations sooner or later. And in a serious technical discussion it's just not very helpfull.

I'm not sure what you mean by the capitalized statement, which usually indicates that the writer is shouting at the top of their lungs in frustration or anger!

If you think that I'm proposing that the ground lead should be shortened to accommodate the scope's shortcomings, then you have misinterpreted post #2409.

If you think that you should be able to use a long ground lead for HF or fast rise time measurements and still get accurate results, then you may benefit from re-reading the post and/or some of the attached excerpts from a variety of sources. Even after you rid your 9302 from the last vestige of noise, or any scope for that matter, that concept is just a physical impossibility.

The jest of post #2409 was in fact to demonstrate that the modifications at that particular level now allow my scope to work with a 6" ground lead the way it should have worked when I first received it. But still within the same limitations that apply to any other scope. These limitations are not dictated by the scope's performance, but are inherent to the characteristics of passive scope probes. Particularly X10 probes.

I provide this information because I believe it to be accurate, potentially helpful to other members, and consistent with the subject and the technical discussion prevalent on this thread. I'm sorry that you don't feel that way, I wonder if other members feel the same way!

[Sarasir]

Hi BBAAHHOO,

thanks a lot for the links to your posts ++

now had the time to look at them a bit and got me your pics and schemes, Later will check them.
Question: Did you also reingeneer/retrace the display supply (not the backlight)?

Would help me if you already have the scheme.

And I guess all of you didn't check that there is another switcher on the main PCB doing the 1.9V.
(still havent read through all of this mass of information here - so I appologise if I missed it)

Greets to Russia, Sarasir

[Sarasir]

Hi TomC,

sorry, sorry, sorry, I certainly do not want to shout at you, but thought just to highlight it as a basic rule. Please believe me I did not know that it means shouting.

Ok, I will go through you post once more and reply later in detail - maybe that I missunderstood it.

Respect

[Sarasir]

Hi tomC,
just reading your post with the pics.

Please can you make a pic series using setup of pic #3 (a bit more amplitude would help) and sweeping the generator from say 50KHz up to say 150Mhz or max to see how much the cores on your probe and the ground lead 'tank circuit' affect the frequency response. A fast rise squarewave test at perhaps 100KHz to 10MHz would also do I think, but don't know if you have such a generator. And please care for correct termination on the output of your generator(s). (If the generators output is 50 Ohm put also a 50 Ohm termination before connecting the probe.

And please do the test twice with the probe in x1 and x 10 mode.

And it would be of good practise if you do the tests first of all as a reference with the generator(s) connected through a BNC cable directly to the scope with enough amplitude so that 'noise << signal'. Here the termination has to be on the scope side of the cable (Generator -> BNC cable -> termination -> scope).

Thanks

[BBAAHHOO]

Hello everyone. Once again - native sources. Just moved and added a filter. Food by the LCD screen native - on a separate board ... as the noisiest. A 1.9V power to the noise is not much compared with by the LCD screen does not touch him ...

[Sarasir]

Hi BBAAHHOO,

how did you check that the contribution to the noise by the 1.9V switcher (converter) is not so much? Have you removed it from the main PCB?

And have you removed all other switchers (converters) from the adapter PCB?

If not:

Have you ever checked with another scope and a probe tip shortened with the ground lead that is placed directly to the top of a little switcher coil how much voltage/spikes will be induced into the ground lead? (preferably the +3.3V and 5.6V coils) (rethorical question as have checked that already!)

Are you aware that the runs (wires) (on the Adapter PCB) to the LCD screen are running along directly under the coils of the switchers.

Don't you think the same voltage/spikes induced into the ground lead will also be induced on the other side of the coils into the display lines?

And how do you think is the relationship between the native display noise and the one induced by the switchers - in case noise should be induced at all?

I could not test that yet because only today I removed the last switcher from the adapter PCB and now I can not power up the scope until I have brought it to work again and have it put in a tin box for shielding (also the backlight switcher I have only removed but not rebuild yet).

I think an indicator that it could be more or less like that is the ferritte core that OWON put over the printed ribbon connecting the display lines.

Hope you understand my english (I'm german).

good luck

[TomC]

Hi tomC,
just reading your post with the pics.

Please can you make a pic series using setup of pic #3 (a bit more amplitude would help) and sweeping the generator from say 50KHz up to say 150Mhz or max to see how much the cores on your probe and the ground lead 'tank circuit' affect the frequency response. A fast rise squarewave test at perhaps 100KHz to 10MHz would also do I think, but don't know if you have such a generator. And please care for correct termination on the output of your generator(s). (If the generators output is 50 Ohm put also a 50 Ohm termination before connecting the probe.

And please do the test twice with the probe in x1 and x 10 mode.

And it would be of good practise if you do the tests first of all as a reference with the generator(s) connected through a BNC cable directly to the scope with enough amplitude so that 'noise << signal'. Here the termination has to be on the scope side of the cable (Generator -> BNC cable -> termination -> scope).

Thanks

Hi Sarasir,

I don't have access to a sweep generator to properly check the frequency response. I've been retired for 20 years and electronics is now just a hobby, so I can't justify expensive equipment although I very much want to have it. When I first started using the ferrites on the probes one other member suggested that they may affect the frequency response because of the added inductance. I remember manually tracking the response of two probes, one with ferrites and one without, first with my audio generator that goes to 100kHz, and next with my RF generator that tops out at 110MHz. The amplitude of the signal was identical at all generator frequency settings. I can't find the post now and I don't remember if I posted pics, I could re-create this again later on and capture some pics at specific frequencies if you want to see it.

I did find a post with more examples using the same setup as #3, but I don't think that it's exactly what you are looking for.

https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg275721/#msg275721

I also have an oscilloscope calibrator with a fast risetime (<4ns) output, but it's designed to connect directly to the BNC with a terminator built in within the male connector. So I'll have to connect the scope probe to that, first with the 6" ground lead and next with the spring ground clip to see the difference in the signal. I can also try with the probe set to X1, but I don't think there will be much difference between the two setups in that case because of the 6MHz bandwidth. Probably shouldn't have made that prediction, half the time my predictions turn out to be off or dead wrong!

OK, I have a few other things to do right now, but I'll probably try the oscilloscope calibrator in a little while and post the results.

[TomC]

The attached images were captured while viewing the fast rise output (<4ns) of my scope calibrator. The calibrator's frequency was set to 1MHz and its output is around 250mV. The intent is to illustrate the effect of different probe configurations on the displayed signal.

#1 & #2 - These two images were obtained with the calibrator's output directly connected to the scope's BNC. These can be considered to be the most faithful representation of the output signal and can be used as a reference to gauge the amount of distortion introduced by the probe configuration in the remaining images. Note that the time base is set to 2ns/div and the rise and fall are within specs.

#3 through #6 - These were obtained with the probe set to X1, first using the 6" ground lead and next using the spring ground clip. Because the probe's bandwidth is only around 6MHz when set to X1, the higher frequency components of the signal are severely dampened before they reach the scope's BNC. As a result the displayed signal has a much slower rise and fall time. Under these conditions the effect of the 6" ground lead versus the spring ground clip has a negligible effect on the displayed signal. This may be construed as an indication that the 6" ground lead can be used when working with lower frequencies and/or slow rise times without risking signal distortion. Note that the time base is set to 20ns/div. Due to the slow rise/fall time the displayed signal would not fit in one screen at 2ns/div.

#7 through #10 - These were obtained with the probe set to X10, first using the spring ground clip and next using the 6" ground lead. In this case the probe's bandwidth is around 100MHz and the higher frequency components of the signal are not dampened before they reach the scope's BNC. As a result the displayed signal has a rise and fall time that closely resembles the direct BNC connection. Under these conditions the effect of the 6" ground lead versus the spring ground clip has a much more pronounced effect on the displayed signal. This may be construed as an indication that the 6" ground lead should not be used when working with higher frequencies and/or fast rise times if minimizing signal distortion is important. Note that the time base in this case is set again to 2ns/div.

[Sarasir]

Hi TomC,

I agree with your interpretation. And there is practically no differenc between BNC directly and via probe recognisable. Just a little and that is rather the probe than the ferrite core I would say. The only thing that is maybe left to test is the influence of the ground lead with and without core but I don't think there will be much difference.

As I alredy said, I respect your remedy and for a user who does not need other setups it is certainly a simple and cost effective solution.

But for resellers and people like me who on one side are frequently working with different types of probes (I have several active- and differential-, one HV, and also some active and passive current probes), and on the other side also have to be able to feed low level signals directly into the BNC of the scope it's practically impossible to adopt that as a permanent solution.

But I understand absolutely. I would nobody just like that recommend to go the way I chose. To reconstruct in a way the whole power design of this machine with all the mechanical effords connected that is only for maniacs like me.

Soon I will post the pics of my reconstructed shielding of the input circuit and also the display power scheme. Took me more than two weeks - about 4 houres a day - to get done with it (had to cut 22  1.4mm threads - I tell you, after your nerves are also done)

And one more fact. On a 350MHz scope I think it's probably not so advisable to 'slow down' the probe with a ferrite core. You know the ringing caused by the spikes is generally above 100MHz so it doesn't bother you so much probably.

Yeterday I removed the display switcher and now the Adapter PCB is depopulated switcherwise. Once got the datasheet(s) from Carrington (thanks a lot once more) is was quite easy to get the scheme. OWON didn't use all options the application circuit offered so perhaps in a few days I can do my first test with all SMPS removed from the scope. I'm looking forward to see the result and especially how much noise was induced by the switchers into the display lines running underneath.

Will report here immediately then.

And, I asked you alredy once but you obviously forgot: Can you please explain in short the mechanism of the belly strap you added. I think it's used often on transformers if I'm right - a chopper band around the outside - but cant' remember having seen that on power transistors or FETs. Have to admitt have not yet read the additional literature concerning denoising perhaps it's in one of these.

And all that basic scope + probe papers - Thanks a lot but actually have many like that from Tek.

But you never know, every book has at least one ore more things explaind in a new way so you eventually understand again a bit more.

Thanks a lot so far and please cross you fingers for me not to send any of those chips to heaven.

[TomC]

And, I asked you alredy once but you obviously forgot: Can you please explain in short the mechanism of the belly strap you added. I think it's used often on transformers if I'm right - a chopper band around the outside - but cant' remember having seen that on power transistors or FETs. Have to admitt have not yet read the additional literature concerning denoising perhaps it's in one of these.

Sorry about that!
I'll be 69  in a few days and have a wife 13 years younger that keeps me hopping!
Once in a while my brain skips a beat trying to keep up!
Here is a link to where I wrote about that:

https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg312258/#msg312258

[lemon]

Hi to everyone, specially to TomC & Carrington.

I see that the member Sarasir had doing a lot of interesting work about eliminate the noise floor of this scope.

Personally, I have stopped the development about noise issue, after the last psu and adapter board changed.

For a long time ago, I will wait a fw development from Owon....   

Now, I see that they give us the version 3.4 but for only newer s/n scopes !
Copy from their site:

SDS7102UP3.4
29 May 2014

The firmware applied to the products with following production batch / serial no. -
SDS71021312xxx, SDS71021319xxx, SDS71021327xxx, SDS71021344xxx, SDS71021352xxx, SDS71021407xxx, SDS71021414xxx, SDS71021418xxx,

Change log - :
1. XY mode - persistence function added ;
2. waveform refresh rate improved ;
3.waveform cutting/ recalling function added;
4. autoset - waveform recognition;
5. channel invert bug fixed;
6. probe attenuation compensation;
7. recorded waveform exported to USB drive
8. automatic measurement - 4 more options available
9. vertical position over-speed movement bug fixed

Have someone, any kind of information what is happening with the older s/n?

[TomC]

Hi lemon!

Glad to see you back in the thread!

I just downloaded the firmware for my unit: 1246xxx and in the upgrade instructions I see the following:

SDS7102? 1122xxx?1127xxx?1137xxx To V2.5.1.*
1143xxx?1149xxx?1152xxx?1153xxx?1203xxx?1209xxx To V2.8.1.6
1211xxx?1219xxx?1223xxx?1234xxx?1240xxx?1246xxx?1251xxx?1303xxx?
1312xxx?1319xxx?1327xxx?1334xxx?1344xxx?1352xxx?1407xxx?1414xxx?
1418xxx To V3.8

Haven't installed it yet, but apparently for anything higher than 1211xxx you get version 3.8.
Don't remember what version is your unit but I think you said it was purchased 2012.

[lemon]

Nice to see you TomC again 
By the way, my wishes for your birthday (soon)...to be very well with your family.

I am looking about fw, with yours serial and the result was the same Ver. 3.3!
You have downloading and installed the fw to your scope or downloading only and saw some txt file?

You have fine memory, mine was 2012 series (1211xxx).

[lemon]

....

Haven't installed it yet, but apparently for anything higher than 1211xxx you get version 3.8.
Don't remember what version is your unit but I think you said it was purchased 2012.

Sorry, now I see it!
What you are thinking about installing?

[Sarasir]

Hi TomC

ahhh, 'TR1' is transformer 1 - OK thought 'TR' means Transistor as the designation for Transformers is usually just 'T'... Everything's clear now. Thanks a lot. (Yeah, keep up with the 'young' lady - Have had that a view times but already feel too old for at nearly 64!!! Need my slow and easy going. But respect)

[TomC]

Sorry, now I see it!
What you are thinking about installing?

Installed it a little earlier and I got version 3.8 now. Haven't checked all of it yet but I see some new features, for example, persist now works in XY mode, which is something I complained about when I was trying to use it with my curve tracer.

Recently bought a Hantek 6022BE PC scope because I thought I could use it exclusively for the XY function (paid only US 70.00 for it), but although it's advertised as being a 20MHz scope it really can only handle about 5MHz well. So even in XY mode the definition is poor, the Owon, even without persist mode, is much better for that function.

So now I'm thinking that I'll use the Owon with my curve tracer and take the 15MHz Tek CRO I had dedicated for that function off my desk. I'll have to build a variable voltage divider so I can properly calibrate the Owon for use with the curve tracer, unfortunately the fine V/div adjustment that we have been complaining about for a long time is still missing in this new firmware.

[TomC]

Nice to see you TomC again 
By the way, my wishes for your birthday (soon)...to be very well with your family.

I am looking about fw, with yours serial and the result was the same Ver. 3.3!
You have downloading and installed the fw to your scope or downloading only and saw some txt file?

You have fine memory, mine was 2012 series (1211xxx).

Sorry Lemon, I didn't catch what you were trying to tell me with the pic when I first read your post, yes, that's the firmware I downloaded, and even though it says V3.3, it's the same file that is used for the later models listed as V3.4. That V3.3 is what I installed on my scope, but it gave me version 3.8, with apparently all the new features that the change log lists for the older newer models. Don't know why Owon makes the listing so confusing, it appears that the same file is used for the whole SDS line.

[TomC]

And one more fact. On a 350MHz scope I think it's probably not so advisable to 'slow down' the probe with a ferrite core. You know the ringing caused by the spikes is generally above 100MHz so it doesn't bother you so much probably.

As far as the conductive GND noise (common mode noise) generated within the Owon, the ferrites on the probe don't make a noticeable difference. If I keep the probe cable away from the LCD, turn off fluorescent lights, computers, and other test equipment, or at least keep the probe cable a good distance away from them, the GND noise test results are nearly identical with or without ferrites on the probe cables. However, the difference is apparent when these outside sources of radiated EMI are active and in the vicinity of the probe cables. So I don't see the ferrites as part of the solution for the conductive GND noise generated within the Owon, rather, they are a way of mitigating the effect of externally radiated EMI generated by other devices. The only exception I know off is the Owon's LCD screen, which has a strong near field of radiated EMI, and can cause the displayed GND noise to go off the screen if you get a probe cable without ferrites near it at the right angle. I've seen the same effect by getting the probe cable near a poorly designed laptop power brick.

In theory ferrites on the probe cable act as a common mode choke and shouldn't affect the differential signal at the probe's input, I've been able to prove this to my satisfaction to 110MHz (the max of my RF generator), but beyond that I can't be certain. I'd like to see someone with more sophisticated equipment test this further.

Although the SDS7102 is sold as a 100MHz DSO, according to tests done by member rf-loop, the front end is capable of nearly 200MHz before the 3db attenuation is apparent right off the box. So in reality, with it's up to 1GS/s sample rate, the scope is usable to well beyond it's 100MHz rating. However, the probes shipped with it are 100MHz, and that's all I have for now. I'm not sure how the GND noise symptoms would manifest themselves with higher bandwidth probes, and of course, I'm also very curious how the GND noise would look like on a 300+MHz scope like yours. I really wish you'd taken some pictures before making all the mods and shared them here. Too late now!

Thanks a lot so far and please cross you fingers for me not to send any of those chips to heaven.

I know what you mean, I had an accident while doing tests on my scope's PSU and smoked the PWM controller, the mosfet, the 4 sense resistors connected to its source, and the common mode choke (LF1). Had to ask Richtek to send me a sample of the PWM controller because I couldn't purchase a replacement locally. However, at the time, I had the new style Owon PSU in my scope and was conducting the tests on a test fixture with dummy loads. You are pretty gutsy to do these modifications without backup spares, so I'll keep my fingers crossed and wish you good luck!

[AndrejaKo]

Hi to everyone, specially to TomC & Carrington.

I see that the member Sarasir had doing a lot of interesting work about eliminate the noise floor of this scope.

Personally, I have stopped the development about noise issue, after the last psu and adapter board changed.

For a long time ago, I will wait a fw development from Owon....   

Now, I see that they give us the version 3.4 but for only newer s/n scopes !
Copy from their site:

SDS7102UP3.4
29 May 2014

The firmware applied to the products with following production batch / serial no. -
SDS71021312xxx, SDS71021319xxx, SDS71021327xxx, SDS71021344xxx, SDS71021352xxx, SDS71021407xxx, SDS71021414xxx, SDS71021418xxx,

Change log - :
1. XY mode - persistence function added ;
2. waveform refresh rate improved ;
3.waveform cutting/ recalling function added;
4. autoset - waveform recognition;
5. channel invert bug fixed;
6. probe attenuation compensation;
7. recorded waveform exported to USB drive
8. automatic measurement - 4 more options available
9. vertical position over-speed movement bug fixed

Have someone, any kind of information what is happening with the older s/n?

Arrghh! Some of those features would have been useful to me. Too bad Owon decided to replace my 1211 main board with a 1209 one when I sent it for repairs.  After installing the update, I got firmware version 2.8.1.6 and check-sum o B0BB1638, same as before, so no new features for those with older units.


Anyway, it's nice to see some new activity in this thread! Thumbs up  for very detailed and very educational content!

[lemon]

Nice to see you TomC again 
By the way, my wishes for your birthday (soon)...to be very well with your family.

I am looking about fw, with yours serial and the result was the same Ver. 3.3!
You have downloading and installed the fw to your scope or downloading only and saw some txt file?

You have fine memory, mine was 2012 series (1211xxx).

Sorry Lemon, I didn't catch what you were trying to tell me with the pic when I first read your post, yes, that's the firmware I downloaded, and even though it says V3.3, it's the same file that is used for the later models listed as V3.4. That V3.3 is what I installed on my scope, but it gave me version 3.8, with apparently all the new features that the change log lists for the older newer models. Don't know why Owon makes the listing so confusing, it appears that the same file is used for the whole SDS line.

Exactly, the fw 3.3 for our series upgrade to 3.8 like fw 3.4 for the newers serial Numbers.
What a strange fw politic!
Sometimes, they improved the fw have the same number, but change the data of uploading file 
Owon all the times are confuse us!

Just, I installed the new fw and here are my notes:

1. XY mode - persistence function added
- I don't look it

2. waveform refresh rate improved
- Seems to be some improvements cause changes at Autoset.
For that reason I repeat the test of Mark Madel (Owon SDS7102 review. youtube) with the trigger output capturing at Chanel II.
The Mark has found that this DSO varies the refresh rate depending time base & memory depth. He had recorded 22.96fps at 1MHz sinus signal (1K depth memory, 1us time base) that dropped to 16.43 when the memory depth was 10M.
With the same conditions, I repeat the test and the results seem to be very faster. With 1K depth memory the refresh rate was 119.07 and with 10M was 36.95. Nice to be good!
Please look at my attachment to verify.

3.waveform cutting/ recalling function added
- Now, at Save menu adding a type of "CutWave", the message that appearing now is "move cursors and press Save to save wave to Udisk. Recall wave btw two cursors by OWON generators".
In fact with this method saves data to .ota files that probably plays to Owon generators !!! 

4. autoset - waveform recognition
- Here is the big differences.
Now when you pressed the Autoset button, the scope try to identify the waveform and if it is success then presents choices depends from what waveform is.
For sinus waveform there is continuous period sinewave or full one period and FFT.
For pulse or square waveform there is continuous pulses, one period, rise pulse, fall pulse
Triangle or something else doesn't recognized and no more choices are available.
Each time you set different waveform must to press the Autoset button to recognized it.
It is pitty that the FFT choice doesn't work with waveform together (split window)
Have in mind, that the Autoset works only if the Autoscale is OFF

5. channel invert bug fixed
- OK, it corrected.

6. probe attenuation compensation;
- Another automatic procedure for relaxing. Connect your probe to a stable 1KHz/5V and scopes makes a diagnosis if this probe has a good compensation or not.

7. recorded waveform exported to USB drive
- It seems to adding some sub-menus to record menu now.

8. automatic measurement - 4 more options available
- They added week rms, cursor rms, duty cycle and Phase?RP
Still is missing the all measurements to real time, just each time that you pressed the "Show All" button.

9. vertical position over-speed movement bug fixed
- It corrected.

Finally, there are some improvements with the more major to me the more stable function of Autoset.
Still missing basic functions like fine V/div adjustment, split window for zoom or fft and something else.