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

[TomC]

Also now for some strange reason, I can detect the waveform of the main transformer of the PSU with a probe next to the PSU vents with back cover on. I think that this wasn't the case before, but I don't really remember holding the probe to the back of the PSU.

This probably has always been there, from the front the z-plate shields must emissions from this transformer, but is open space from the back. I think it would be beneficial to reduce these emissions, they can easily re-radiate of other elements and eventually become CM noise. In my opinion, this was partially to blame for Lemon's and Carrington's negative results with the conductive paint. I'm planning on trying some noise control approaches for this transformer. A simple one that I'll probably try first is a belly strap.

[AndrejaKo]

What does term "belly strap" mean in this context?

[Carrington]

A simple one that I'll probably try first is a belly strap.

Be careful with that.

What does term "belly strap" mean in this context?

See attachments.

http://www.righto.com/2012/11/teardown-of-mysterious-kms-4-port-usb.html

[AndrejaKo]

Thanks a lot! It's clear to me now.

[lemon]

I''ll do a trial to a test Nickel painted plastic, with a mix of HCL (conc. 7%) and H2O2 (conc. 35%).
From wikipedia read that the Nitric oxid is very well to Nickel dissolution, populate product about this is the "aqua forte".
...

I painted with Nickel spray a small plastic and I try to removed today by a mix of HCL (conc. 7%) and H2O2 (conc. 35%). This solution is usual for cooper removed from my diy pcb's.
Unfortunately, nothing! I leaved it 4 hours and nothing! Nickel seems not to react with this solution. Perhaps it needs to warm but it is very complex for now.

Now, I am looking about Nitric oxid.

[Carrington]

I painted with Nickel spray a small plastic and I try to removed today by a mix of HCL (conc. 7%) and H2O2 (conc. 35%). This solution is usual for cooper removed from my diy pcb's.
Unfortunately, nothing! I leaved it 4 hours and nothing! Nickel seems not to react with this solution. Perhaps it needs to warm but it is very complex for now.

Now, I am looking about Nitric oxid.

It should be the other way, I think, i.e. HCL (conc. 25-35%) and H2O2 (conc. 10%).
Where did you get the Nitric oxide?

[lemon]

I didn't get nitric oxide, yet. I am looking for.
I found a super market product (tuboflo) that contains nitric oxide but contains and NaOH also.

[Carrington]

I didn't get nitric oxide, yet. I am looking for.
I found a super market product (tuboflo) that contains nitric oxide but contains and NaOH also.

Is something like this?

[lemon]

There are tub.o.flo series, gel and powder.
The first used as is, the second needs water to act.
The powder serie has two versions, the one acts with cold water (blue versions) and contains Nitric oxide and NaOH, the other acts with hot water (red versions) and contains NaOH only.

If you read the instructions of the powder version (cold water), needs a lot of attention with the water...

[lemon]

I have news about how to remove the Nickel Shield.
After, no success with blue tuboflo, I come back with the mix of HCL+H2O2. I make a fresh 37% HCL and a fresh 35% H2O2.
From the HCL(37%) I make a 14% solution (this done with warm water).
I left the front plastic case of osciloscope into this solution for 4-5 hours.
After that there is no clean complete but after drying I see that there is no any continuity of surface (I measure it  with multimeter). Seems like to away the Nickel layer and still a paint lacquer light gray colour.
Photos I''ll upload later.

I tested it complete open (only with the front case) and noise decreased by 10mV.
The same period with the test, I had took some flat ferrites from farnell.
Before I had test the area of tft flat cable that joined with adapter board by the probe tip and I have seen some major noise over there. It was a mysterious combination noise of tft and psu TR1 transformer.

For that reason I decide to order two flat ferrites from Farnel, a FPC-31-12K 26mm KE Kitagawa flat ferrite and a SSC-33.5-20M 26mm KE Kitagawa flat ferrite (datasheet: http://www.farnell.com/datasheets/31877.pdf.
The FPC has better result to noise. With complete open oscilloscope (only front case) I came to 34-44mV (normal or peak) and 20-24mV (Average 16/100-200usec)

Finaly, it wasn't accident that Owon puts this ferrite to this area at the later oscilloscope versions.

[akis]

Hello, last time I was here this thread had like 50-60 pages, now it is 135!

Wanted to ask has anyone fixed their SDS 7102 noise problems? Did Owon make a new PSU board which was touted to be the route? Any other ideas?

[rf-loop]

Hello, last time I was here this thread had like 50-60 pages, now it is 135!

Wanted to ask has anyone fixed their SDS 7102 noise problems? Did Owon make a new PSU board which was touted to be the route? Any other ideas?

Today there is new PSU and adapter board. (have been some time)

Also there is solutions for these manufacturing versions what show extra high ground RF noise.


It need also here remember that IF signal is clean in oscilloscope BNC input there have not been any noise issue related to this "noisy GND" issue.
Owon have extremely low noise  front end. There is available lot of tests about it. Even with these "noisy GND" versions.

[akis]

Hello, last time I was here this thread had like 50-60 pages, now it is 135!

Wanted to ask has anyone fixed their SDS 7102 noise problems? Did Owon make a new PSU board which was touted to be the route? Any other ideas?

Today there is new PSU and adapter board. (have been some time)

Also there is solutions for these manufacturing versions what show extra high ground RF noise.


It need also here remember that IF signal is clean in oscilloscope BNC input there have not been any noise issue related to this "noisy GND" issue.
Owon have extremely low noise  front end. There is available lot of tests about it. Even with these "noisy GND" versions.

Is it easy to get the new PSU/adapter board and fit it in? Where can I get it from?

[lemon]

The new PSU & Adapter board that rf-loop said is the Adapter Ver. 3.2 or 3.3 (the only difference is a smd bypass capacitor) and the PSU with unkonwn mark that Owon produce after PSU PCB-T115-J Rev.3.
Owon sends a kit that including the new psu board and one smd capacitor (https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg257623/#msg257623), but this is OK if you have adapter version 3.2, if you had an older version than 3.2 you need a new adapter version or to modificate it.
For that the best solution is to communicate with your Owon dealer.

Here are the photos of these new boards: https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg273905/#msg273905
https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg274030/#msg274030

If you had the adapter version 3.2, there is no need to take the 3.3 version, you can put the smd alone.

With these boards and a flat ferrite to flat tft display cable, the noise decrease to 25-35mV (10X).

Member like rf-loop and Siri have presented some modifications to older adapters with success. Have these wonderfull projects to my mind, I had doing some trials to decrease my gnd-noise and I had success.

Look the following links.
PSU PCB-T113-J Rev.6 (through-hole components) : https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/?action=dlattach;attach=57753;image
Suggestion to PCB-T115-J rev4 PSU board = https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg276411/#msg276411

Adapter Version 3.0, first modifications = https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg271798/#msg271798
Adapter Version 3.0, last modifications = https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg290177/#msg290177
https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg289496/#msg289496

[akis]

The new PSU & Adapter board that rf-loop said is the Adapter Ver. 3.2 or 3.3 (the only difference is a smd bypass capacitor) and the PSU with unkonwn mark that Owon produce after PSU PCB-T115-J Rev.3.
Owon sends a kit that including the new psu board and one smd capacitor (https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg257623/#msg257623), but this is OK if you have adapter version 3.2, if you had an older version than 3.2 you need a new adapter version or to modificate it.
For that the best solution is to communicate with your Owon dealer.

Here are the photos of these new boards: https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg273905/#msg273905
https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg274030/#msg274030

If you had the adapter version 3.2, there is no need to take the 3.3 version, you can put the smd alone.

With these boards and a flat ferrite to flat tft display cable, the noise decrease to 25-35mV (10X).

Member like rf-loop and Siri have presented some modifications to older adapters with success. Have these wonderfull projects to my mind, I had doing some trials to decrease my gnd-noise and I had success.

Look the following links.
PSU PCB-T113-J Rev.6 (through-hole components) : https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/?action=dlattach;attach=57753;image
Suggestion to PCB-T115-J rev4 PSU board = https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg276411/#msg276411

Adapter Version 3.0, first modifications = https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg271798/#msg271798
Adapter Version 3.0, last modifications = https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg290177/#msg290177
https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg289496/#msg289496

OK, If I understand this right, there are many versions of the adapter boards, from 3.0, 3.2, 3.3 and if I have anything < 3.2 then I need a new adapter board from Owon?
If my adapter board is > 3.2 then all I need is to change a SMD capacitor?

And in addition I always have to use a ferrite choke to attach to the display cable (do Owon also send me the ferrite?)

Have I got it right?

[lemon]

There are many adapter versions, I think older than 3.0.
Right, if you have adapter version 3.2 there is no need to change it to 3.3

When you have bought the SDS7102 or what serial number without 3 last digits have you?
Please do it this test and tell us how many mV: https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg255469/#msg255469

There isn't the flat ferrite in Owon kit. In early versions of Owon this ferrite including, there isn't to the older versions.

[akis]

There are many adapter versions, I think older than 3.0.
Right, if you have adapter version 3.2 there is no need to change it to 3.3

When you have bought the SDS7102 or what serial number without 3 last digits have you?
Please do it this test and tell us how many mV: https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg255469/#msg255469

There isn't the flat ferrite in Owon kit. In early versions of Owon this ferrite including, there isn't to the older versions.

My serial number is SDS71021211675 version 2.8.1

I did the test as per instructions and got 585mV !!!!

[akis]

Here is a picture:

[Carrington]

Here is a picture:

Oh my god.

"Owon have extremely low noise  front end. There is available lot of tests about it. Even with these "noisy GND" versions."

[akis]

I think, if you care to look back, it was me that mentioned maybe a year ago, that my scope was "faulty".

These are extracts of my comms to the UK supplier :

Friday, 28 December 2012 5:09 pm
I believe the Owon sds-7102V may be defective : at low level signals there is a lot of noise, and the curve does not stand still on the screen. Is there a place in the UK that can perhaps repair it?


29 December 2012 2:19 pm
The problem is the scope has random "noise" which makes it almost impossible to view low voltage signals.

9 January 2013 7:53 am
Yes the problem still exists with the limit set to 20M.

11 January 2013 7:59 am
The problem is the same for both channels and I have tried 4 different probes. It is the same problem all the time.

24 January 2013 8:57 am
I have replied to you that there is a problem with the scope at low signal voltages. It affects both channels and I have tried 4 different probes. The problem is not with the probes, it is with the scope. You have sent me a lot of emails asking me all these questions, but you have not yet told me how you are proposing to repair or replace my scope.

[rf-loop]

"Owon have extremely low noise  front end. There is available lot of tests about it. Even with these "noisy GND" versions."

My original text:

It need also here remember that IF signal is clean in oscilloscope BNC input there have not been any noise issue related to this "noisy GND" issue.
Owon have extremely low noise  front end. There is available lot of tests about it. Even with these "noisy GND" versions.

And I can stay behind these my word.

[akis]

"Owon have extremely low noise  front end. There is available lot of tests about it. Even with these "noisy GND" versions."

My original text:

It need also here remember that IF signal is clean in oscilloscope BNC input there have not been any noise issue related to this "noisy GND" issue.
Owon have extremely low noise  front end. There is available lot of tests about it. Even with these "noisy GND" versions.

And I can stay behind these my word.

Are you trying to see that I am doing something wrong? What do you mean by "if signal is clean ..." ? Are you saying that I am doing something to pollute the signal? If yes then please please show me how to "unpollute" it. I only want it to work after all

[rf-loop]

"Owon have extremely low noise  front end. There is available lot of tests about it. Even with these "noisy GND" versions."

My original text:

It need also here remember that IF signal is clean in oscilloscope BNC input there have not been any noise issue related to this "noisy GND" issue.
Owon have extremely low noise  front end. There is available lot of tests about it. Even with these "noisy GND" versions.

And I can stay behind these my word.

Are you trying to see that I am doing something wrong? What do you mean by "if signal is clean ..." ? Are you saying that I am doing something to pollute the signal? If yes then please please show me how to "unpollute" it. I only want it to work after all

No, it was lightweight note to carrington about how to quote.

[AndrejaKo]

Here is a picture:

Welcome to the club! I have scope from same batch and it shows similar results!

My first advice to you, if you want to try to modify the PSU, is to change the MC34063A with one from a reputable manufacturer. I got some 15 K decrease in temperature just from that (but it could be that my MC is pretty problematic). Next, removing the current sense resistor for MC removed much of the noise. Another helpful step for me was to place a metal bar next to the PSU<->adapter cable and then place small SMD capacitors from each line to the bar and connect the bar to ground(I'll try to dig up link with images of that). With that, I came close to some 200 mV of noise with 150 MHz probes. Still the PSU noise remains.

There are some problems with adapter noise as well, but I haven't investigated the much, since I had numerous problems with the PSU (some of them made by me), so I can't tell much about that board. For example, on my PSU, in the main switch, one switch had contact resistance of around 100 ohms and the second had resistance of around 10 ohms, so I had to open the switch and work a little bit on  the contacts themselves.

Also does anyone know how much the adapter board costs? I remember that Owon used to ask $50 for PSU, but I don't think anyone mentioned adapter board price.

[lemon]

I have a suspicious that the psu of Akis is similar to AndrejaKo, very bad gnd_noise!
I have a suspicious that with this serial number, you must have an adapter version 3.0

Akis, can you open the oscilloscope gently?
There is a teardown video, how to dismantle the unit. Perhaps the upper gray button to open it with a strong pull it by pliers (put a cloth between pliers and button)


My opinion if you have PSU board PCB-T115-J rev4 (https://www.eevblog.com/forum/testgear/review-of-owon-sds7102/msg276171/#msg276171) is to buy a new one, than to modificate it.

If all the above happens, contact to your dealer and ask him to request warranty cover from Owon about this issue. Attach the captured gnd-noise that you have upload to us. Ask from him to coverage the psu and adapter board by warranty and you coverage the shipping cost.