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

[aghp]

In your one image where probe is directly connected to probe comp output.
This kind of noise is not normal.  And it is in this signal low level part as much as signal top level part.
Where from it come, it need find.  Is it from inside or outside?
It is pity you can not get trusted lower level signal with known low noise level.

[akis]

I think it is coming from the scope itself. Something in the signal path does this.

I have contacted the supplier, and they said it has a 3 year warranty, and that they will send me instructions of how to get it repaired.

So I am waiting...

[akis]

Actually, could you please perform the same test as I did and post your picture? You only need 2 resistors, a 10K and a 470R.

[aghp]

I think it is coming from the scope itself. Something in the signal path does this.

I have contacted the supplier, and they said it has a 3 year warranty, and that they will send me instructions of how to get it repaired.

So I am waiting...

Yes, this can suspect. But proofing it is other game.
Also there is only small signs but 1kHz rise and fall can not normally detect from open inputs captured noise. But you have these and clearly.

Picture A.
10k + 500ohm
Probe 1x (forget to change scope probe set to 1x so it is there 10x)

Enviroment not very clean but reasonable.

Picture B

Exactly all same. Added 137MHz RF field (clean quite stable 3W output to bad small pen style antenna and antenna around over 3meter away from scope..  (I do not know anything how this small around 15cm antenna radiate around, I have here not available now field strenght measurement)
Note also that probe itself  is low pass filter when it is 1:1 mode.

AND note also: Oscilloscope have (partially) loosed trig to this 1kHz square! It "looks like" it trigs randomly rising or falling edge but not full random related to 1kHz becouse this RF disturb trigger circuit.

This is only imagine that many kind of noise can affect very easy. Probe tip is 500ohm from GND. Probe BW is around 6MHz  But it is still nice antenna.
This give only some idea that always is good to suspect everything and then step by steb close different things out and finally it know - if know.

[EEVblog]

NOTE: PLEASE READ:
It has been bought to my attention that users "aghp" and "rf-loop" who have been posting to this thread (and others) are in fact the same person. They have posted under identical IP address at various times, but generally have tried to avoid doing that by using different IP's for the two accounts.
Given that "aghp" is a dealer, then this is potentially unethical (I have not read all thread/posts to see what has been said by either though). aghp's account has thus been suspended.
Given rf-loops good technical content, he is welcome to continue to contribute to the forum under the "rf-loop" handle, subject to the usual rules.

Perhaps he'd like to explain?

Dave.

[nctnico]

Note that due to shortage of IP4 adresses providers (especially the ones offering internet access through 'GSM' networks) use NAT to share a few IP addresses between a lot of users. In other words: nowadays you can't identify users strictly by their IP address.

[marmad]

Note that due to shortage of IP4 adresses providers (especially the ones offering internet access through 'GSM' networks) use NAT to share a few IP addresses between a lot of users. In other words: nowadays you can't identify users strictly by their IP address.

Be that as it may, what Dave posted is true - as some here have known for awhile.

[EEVblog]

Note that due to shortage of IP4 adresses providers (especially the ones offering internet access through 'GSM' networks) use NAT to share a few IP addresses between a lot of users. In other words: nowadays you can't identify users strictly by their IP address.

There are others things that point to it too, not just IP. But even if you just had the IP, two people with the same IP, posting in the same forum, on the same topic, with the same passion, with the same technical knowledge?
Calculate the odds.
rf-roop is aghp
If he's not, he'd be right back here explaining how we got it all wrong...

Dave.

[akis]

I am not sure what the benefit of having two accounts might be, however aghp has been helpful to me recently regarding my problems with a defective Owon scope.

[Mark]

There are others things that point to it too, not just IP. But even if you just had the IP, two people with the same IP, posting in the same forum, on the same topic, with the same passion, with the same technical knowledge?
Calculate the odds.
rf-roop is aghp
If he's not, he'd be right back here explaining how we got it all wrong...

Dave.

I have known that since I joined here (worked it out while reading ALL of this thread )  and didn't point it out because I thought it was some kind of allowed arrangement.  One never quoted the other, bu they both talked in the same way and misspelled the same words. 
Still, there is no denying that he has contributed significantly and positively to this thread. 

[electroguy]

There are others things that point to it too, not just IP. But even if you just had the IP, two people with the same IP, posting in the same forum, on the same topic, with the same passion, with the same technical knowledge?
Calculate the odds.
rf-roop is aghp
If he's not, he'd be right back here explaining how we got it all wrong...

Dave.

could be 2 people working in the same business, hence the same internet connection (and possibly even the same computer) and same knowledge etc...

but the odds are they are probably the same person.

[jahonen]

Quite funnily, I have suspected this for a while due to the language they used, e.g. what is the possibility that two independent persons both spell "again" as "agen". Take a look at the posts. I have heard lot of good things from aghp/rf-loop and have absolutely nothing against him, but just wondering why use two accounts?

Regards,
Janne

[akis]

Well I bought my scope from Amazon, UK, from a company that purports to import them to the UK. So I paid 100 pounds extra compared to ebay, but at least I thought I was buying from the UK, so avoid all hassle with customs etc.

The scope took many weeks to arrive, so obviously it came straight from China. Additionally now that it is broken, I have been exchanging emails with the UK company, who appear to be signing their emails with a US new jersey address, and they have been asking me dozens of questions like "did you earth the probes?" "did you try both channels" "did you try alternative probes" and all that cr*p. My first email to them I believe was December 28, and as yet I have not received solid instructions on how they propose to repair it or replace it.

Crossing fingers they will honour their 3 year warranty.

[rf-loop]

Well I bought my scope from Amazon, UK, from a company that purports to import them to the UK. So I paid 100 pounds extra compared to ebay, but at least I thought I was buying from the UK, so avoid all hassle with customs etc.

The scope took many weeks to arrive, so obviously it came straight from China. Additionally now that it is broken, I have been exchanging emails with the UK company, who appear to be signing their emails with a US new jersey address, and they have been asking me dozens of questions like "did you earth the probes?" "did you try both channels" "did you try alternative probes" and all that cr*p. My first email to them I believe was December 28, and as yet I have not received solid instructions on how they propose to repair it or replace it.

Crossing fingers they will honour their 3 year warranty.

Please do you have 1 pcs 50ohm bnc terminators?

If you have:

Default scope.
Set oscilloscope menu probe setting to 1x for  both channel.
Turn both channels to 5mV/div
1ms/div speed.
Turn memory to 1M
Turn acquire to Peak mode!
In all cases keep both traces visible.


1.

Connect one BNC terminator to ONLY CH1  but so that its center pin do not make contact (you pull and push you look trace you find where it connect and where not.
Take TFT image to usb or computer.
Push terminator fully in (it make connect) and take image agen.
(in both images keep CH2 just open)


2.

Connect one BNC terminator to ONLY CH2  but so that its center pin do not make contact (you pull and push you look trace you find where it connect and where not.
Take TFT image to usb or computer.
Push terminator fully in (it make connect) and take image agen.
(in both images  keep CH1 just open)

Show these 4 images.

If I try help you for arrange RMA with Owon I need know real data what show to me that it is broken. It seems that your seller is just in class "we sell nice boxes but we do not know what they are"
Opinion is not enough in this case - it need data. (I do not want burn my fingers with Owon (becouse I need  use "kitchen door" for help others than my customers) if later there find that reason for noise is example some (very bad and strange) electromagnetic noise in your enviroment. I do not try tell that it is my suspect - only I want close this small posibility out first)

[AndrejaKo]

Hey guys! I just wanted to ask: Did it happen to any of you that you press the power button on the scope and nothing happens?

Usually as soon as I press the top power button the screen turns on and I hear fan working, but sometimes even after several tens of seconds, nothing happens. If I turn it off and on again, it always starts fine.


Oh, and since nobody mentioned it, it seems that in the new 2.8.2 firmware, there's a trigger frequency counter for both channels available. Previously one one would be visible in ALT mode.

[rf-loop]

Hey guys! I just wanted to ask: Did it happen to any of you that you press the power button on the scope and nothing happens?

Usually as soon as I press the top power button the screen turns on and I hear fan working, but sometimes even after several tens of seconds, nothing happens. If I turn it off and on again, it always starts fine.


Oh, and since nobody mentioned it, it seems that in the new 2.8.2 firmware, there's a trigger frequency counter for both channels available. Previously one one would be visible in ALT mode.

Yes I have seen failed power supply.
Look front panel power led first after you connect power cable and sidepanel  primary switch  on.
Then how it light when you push power switch on (top of scope).
What is your scope original displayed version and serial number. (no need last three digits).

In ALT mode both channels have own separately settable trig and  it also show both channels trig frequency. This function have been as long as I remember.

[AndrejaKo]

Interesting! I must have missed the frequency somehow in ALT mode before.


The original version was 2.6.2, if I remember correctly. Serial number is SDS71021211xxx

I have the version with the battery. When I first turn the power on on the side switch, the LED is orange for a while and then turns green with the battery installed. Without the battery, it turns green immediately.
 
Right now my battery is discharged, so when I press the power button with the side power on, the LED changes color from orange. I'm not sure how to exactly describe it, but it seems to be redder than when the scope's main power button is off. After some time, it turns green.

When the "problem" occurs, the LED stays off, like everything else.
I'm sorry for providing incorrect information. The LED is green. If it was orange before turning on, it turns green.

[rf-loop]

When the "problem" occurs, the LED stays off, like everything else.

Take battery out.

Use it some time without battery and note if you find this same situation where power led stay off after power plug is connected and sidepanel switch ON.

Have it never shut off itself? (exept battery discharged)

[AndrejaKo]

No, it never turned itself off.  I never did run the battery past the low capacity warning, so it never turned off due to discharged battery. I'll let it run without the battery for a while and report what happens.


The problem usually occurs when the scope wasn't used for a while, so it may take some time for me to determine if the problem disappeared.

Also thanks for help.

UPDATE: It happened again without the battery.

[bill2010]

I recently purchased a SDS7102 and have similar noise issues as user akis is experiencing.  As far as I can tell, the noise is being generated by the scope itself and seems to be somewhat broadband in nature, running from around 80 - 100 MHz.  It is NOT in the actual signal path (for me at least), since it can be eliminated when I use straight coaxial cables instead of probes or jumpers.  I also know it is not environmental as I can pick it up on my Tek DPO, but only when the Owon is powered on.  Happy to run any tests or post pictures to better explain this.  My serial is SDS71021246xxx and it is running 2.8.2 firmware.

I am assuming I have a bad unit with some type of shielding / grounding problem, because the level of noise being generated is far from subtle and should have been easily picked up during product EMI testing.

--Bill

[tinhead]

i'm looking for someone, with signal gen, to run some frequency response tests on the Owon SDS series:

https://www.eevblog.com/forum/reviews/frequency-response-of-your-dso/

[rf-loop]

i'm looking for someone, with signal gen, to run some frequency response tests on the Owon SDS series:

https://www.eevblog.com/forum/reviews/frequency-response-of-your-dso/

Here is some but later after I have time I can run better...

I have not system where I can measure direct level from scope BNC for keep this level flatness inside some acceptable tolerances.
But I have power meter and I can look my signal generator output signal flatness directly to power head. It do not tell "anything" what is level in scope BNC after it is connected  there. (it is not 50ohm impedance over example 0-500MHz due to oscilloscope input reactance.)
It can perhaps littlebit help with attenuator but.. then can not measure other than only lowest (direct) voltage band.

But still it can do measurement and it is better than nothing.
I can use HP8644B what is enough accurate for this measurement.

But now some days busy with other things.

[tinhead]

I've used calibrated R&S SMX which is specified as < 1.5dBm over full range, however i know in the range i've used it's ±0.25dBm, which is more tha good enough. HP8644B is for sure good enough, it's < 1dBm (and typical i think less than ±0.5dBm) over full range - which we don't need it anyway.

[akis]

Well I bought my scope from Amazon, UK, from a company that purports to import them to the UK. So I paid 100 pounds extra compared to ebay, but at least I thought I was buying from the UK, so avoid all hassle with customs etc.

The scope took many weeks to arrive, so obviously it came straight from China. Additionally now that it is broken, I have been exchanging emails with the UK company, who appear to be signing their emails with a US new jersey address, and they have been asking me dozens of questions like "did you earth the probes?" "did you try both channels" "did you try alternative probes" and all that cr*p. My first email to them I believe was December 28, and as yet I have not received solid instructions on how they propose to repair it or replace it.

Crossing fingers they will honour their 3 year warranty.

Please do you have 1 pcs 50ohm bnc terminators?

If you have:

Default scope.
Set oscilloscope menu probe setting to 1x for  both channel.
Turn both channels to 5mV/div
1ms/div speed.
Turn memory to 1M
Turn acquire to Peak mode!
In all cases keep both traces visible.


1.

Connect one BNC terminator to ONLY CH1  but so that its center pin do not make contact (you pull and push you look trace you find where it connect and where not.
Take TFT image to usb or computer.
Push terminator fully in (it make connect) and take image agen.
(in both images keep CH2 just open)


2.

Connect one BNC terminator to ONLY CH2  but so that its center pin do not make contact (you pull and push you look trace you find where it connect and where not.
Take TFT image to usb or computer.
Push terminator fully in (it make connect) and take image agen.
(in both images  keep CH1 just open)

Show these 4 images.

If I try help you for arrange RMA with Owon I need know real data what show to me that it is broken. It seems that your seller is just in class "we sell nice boxes but we do not know what they are"
Opinion is not enough in this case - it need data. (I do not want burn my fingers with Owon (becouse I need  use "kitchen door" for help others than my customers) if later there find that reason for noise is example some (very bad and strange) electromagnetic noise in your enviroment. I do not try tell that it is my suspect - only I want close this small posibility out first)

I have bought two brand new BNC terminators 50R and tried them. There is absolutely no difference between "fully inserted plug" or "just touching". I attach a picture which should count for all the four that you have asked me.

The Owon people have come back to me and told me not to expect too much from the scope as it is a cheap scope. However I genuinely think mine is broken as there is all this noise which renders the scope almost useless for signals below 100mV RMS or thereabouts.

[bill2010]

The Owon people have come back to me and told me not to expect too much from the scope as it is a cheap scope. However I genuinely think mine is broken as there is all this noise which renders the scope almost useless for signals below 100mV RMS or thereabouts.

akis -- I believe my scope is having the same noise issues as yours and I find it hard to believe (as do you) that Owon would classify this as acceptable performance.  I am attaching screen shoots. The first two are of my SDS7102 and Tek DPO20204 attached to the same signal generator using their supplied probes.  The Tek is being triggered off of the Owon's trigger out since the noise seems to be synchronized with the Owon's sweeps and this allows it to be better captured visually.  The next is of the Tek connected to the same signal generator, but with the Owon turned off and it triggered internally.  The last is of the Owon connected to the signal generator using a coaxial cable and a 50 Ohm straight through terminator.

Comments anyone?