DSO measurement : Reference signal / Expert's eyes suggestion?

[nvr0hk]

Hi All,

  may some Expert's eyes have some comments about this screenshot from a new DSO sampling it's reference signal?





  I don't tell more because I wouldn't influence you in either way.

  Thanks.

[AndyC_772]

OK, it looks as though the scope is only 2 channel but has a proper intensity graded trace - full marks for that. I'd be mentally comparing it against something like a Rigol 2000 series, would that be fair?

The traces themselves (especially in the top image) look a little noisy, which is fine if that means it's a reasonably high bandwidth model - say, 350 MHz. If it's anything less than that, maybe it's worth revisiting how this compares against its direct competition.

The biggest issue for me, though, is the look of the UI. The font, the style of the buttons and the overall layout reminds me of the Unix terminals I used nearly 20 years ago, and it screams "cheap Chinese scope". It shows a lack of polish and refinement, and experience has taught me that if a UI looks bad, it won't work well either. It needs to be de-cluttered, eg. get rid of all the measurements unless they're specifically enabled - but that's just one usability issue, and I'd be surprised if it were the only one.

To be taken seriously, and not just dismissed as yet another not-quite-finished Chinese product (regardless of where it's actually designed and built), what it really needs is a UI overhaul from someone with specialist experience in this area and some properly decent graphic design skills. It's an area in which the established quality manufacturers (I'm thinking Agilent and Tektronix here) are streets ahead, and it makes a huge difference.

[amyk]

Agreed the signal looks a little noisy, but I don't think there's anything wrong with the UI; font is big enough, indicators are obvious. The only minor issue I see is "KHz" instead of "kHz" (they got mV and ms right...)

To be taken seriously, and not just dismissed as yet another not-quite-finished Chinese product (regardless of where it's actually designed and built), what it really needs is a UI overhaul from someone with specialist experience in this area and some properly decent graphic design skills. It's an area in which the established quality manufacturers (I'm thinking Agilent and Tektronix here) are streets ahead, and it makes a huge difference.

Sometimes deliberate graphic design results in something worse.

[grumpydoc]

The graphics look rather java awt-ish (so possibly not wrong about the unix connection).

[nvr0hk]

I'd be mentally comparing it against something like a Rigol 2000 series, would that be fair?

yes, especially near the same scheme front-end.

The traces themselves (especially in the top image) look a little noisy, which is fine if that means it's a reasonably high bandwidth model -

Manufactured recently, normally this series scale from 60MHz to 200MHz.

say, 350 MHz. If it's anything less than that, maybe it's worth revisiting how this compares against its direct competition.

Brand new, "rated" "200MHz"...

[Bored@Work]

It is a Hantek/Tekway. The one we have a 1500+ comments thread somewhere here.

The signal on CH1 in the first picture is negative. If both channels are feed from the probe compensation signal it would mean that either someone selected the internal invert function or something is broken.

Regarding the UI, typical Chinese copy of older oscilloscopes from the west, no Java at all involved.

[AndyC_772]

I think that's what the little yellow icon 3rd from left on the bottom row is supposed to indicate - CH1 is indeed inverted.

[marshallh]

The only thing I can tell is that its a cheap bleh chinese scope.

Now get yourself a <1ns rise time pulse generator or function gen and see how its step response looks.

[PA4TIM]

Hard to say, if it is the internal calibrator and my Hameg made such a noisy trace from that, it went straight out the window.
But it can be a perfect scope attached to a crappy signal generator with lousy coax and no termination
Or a crappy scope connected through fine material to a perfect genertor
It can be a crappy generator and a crappy scope.

My Rigol DS1102 was as noisy as this picture.

350 MHz Hameg coupled to a HP8640

[tinhead]

The only thing I can tell is that its a cheap bleh chinese scope.

and you must be an expert, are you? No, don't answer this, simply read what i wrote i learn from it.

So let's compare the "cheap bleh chinese scope" with U.S. made 18k+ USD scope, TDS700 series.
Some background, TEK TDS 700 series is using 10DIV for full scale, with 50pix per DIV. Honestly
i don't remember exactly if TEK is using 510 or 500pix for full scale, but this didn't matter here.

The 1kHz Tekway/Hantek calibrator signal measured with TEK, we can see about 10pix of noise are clearly there:



which looks very similar to what measured on Tekway/Hantek (they using as well 10DIV high full scale with 50pix per DIV vertically)
as well about 10pix of noise:





So there is nothing wrong with the scope/firmware/pixels/what so ever, the noise IS there.

Now get yourself a <1ns rise time pulse generator or function gen and see how its step response looks.

here we go mr expert; rise pulse (pulse gen from AN94 version http://www.linear.com/docs/4183)
attenuated with Mini-Circuits vat-20+ for optimal damping (compare it to Figure 13):



and here frequency response, it look flat enough, not only for "cheap bleh chinese scope":

Hi All,
  may some Expert's eyes have some comments about this screenshot from a new DSO sampling it's reference signal?

first of all i would recommend to watch some of the video here (e.g. ground lead)

https://www.eevblog.com/forum/beginners/oscilloscope-training-class-(long)/

You have to understand few things about DSOs:

1 . the noise is everywhere, when you use long ground leads your scope will pickup even noise
from Argard spacesheeps flying light years away from here.
And btw, test probe compensation signal from 18k+ TEK, measured with exact same probes and
exact same (wrong) way looks even worse:




2. don't expect signals like this, without tricks (filters, shielding, avg sampling) they didn't exists




3. learn what your scope is capable to do. In long timebase ranges Tekway/Hantek is capable of using 2pix per bit
in single window mode



and 1pix per bit in dual window mode. This look much better for human eyes, but actually there is no real difference,
it's only what the firmware/display is doing with the signal




Another example; between 800ns/DIV your scope is using fine pixeling, the signal looks "better"




but with coarse pixeling (between 40s/DIV and 2us/DIV) it looks "bad" again




However, it is only difference of using more or less pixels per bit and/or filtering. I remember 3yr ago the
Tekway/Hantek firmware was working exact vice versa (shor tb high noise, long tb low noise), they changed
it however to reduce aliasing and waveform distortion. I don't mind, i know the noise really there (see the TEK00000.png).


4. accept that (all) digital scopes are showing what the firmware reconstructed from the acquisition data,
many things depends on manufacturer "likes", not on the real data quality.

[PA4TIM]

Not a very fair compare, that Tek design is allmost 13 years old, a scope with that specs , from Tek or Agilent, will not cost near 18K today.  ( if I remember well that whole TDS serie was not famous for low noise, it was the time Tek was starting to loose customers to Agilent)

But for the rest I think you wrote an nice informational piece. Indeed software filtering ect can do a lot. ( by the way the picture from my Hameg is just in auto mode, no filtering ect, full bandwidth).

And I still think that is a pretty lousy calibration signal fom the tekway. I get the same noisefree picture on my Hameg whitout filtering as the Tekway gets with filtering. (Also if connected to a good analog scope) so that Tekway calibratorsignal  is pretty noisy.

As a compare, 800 ps seconds, also from tunneldiode pulser, connected from a GR connector to bnc adapter, 20 dB attenuator, normal 50 Ohm cable to the scopes own 50 Ohm  terminated connector

[tinhead]

Not a very fair compare, that Tek design is allmost 13 years old, a scope with that specs , from Tek or Agilent,
will not cost near 18K today. 

oh well, knowing TEK for sure 5k, DPO2000 is too small, even DPO3000 is in some specs not good
enough to beat TDS7xx and costs already lot of $$$.

And I still think that is a pretty lousy calibration signal fom the tekway...

no doubt, but for probe calibration good enougt ^^ . It think it could be easy modified, but well, for what? That's only cal signal.

Indeed software filtering ect can do a lot. ( by the way the picture from my Hameg is just in auto mode

Not only filtering, sometimes even such simple things like waveform shading is making the "difference" for human eyes.
When i look on your Hameg screenshot, it seems that Hameg is as well using 2pix per bit and i assume
10DIV full scale. But there is nice difference, the shading diff between top and bottom wave dots/line.

Hrhr, maybe i should ask Tekway to implement it in similar way, this could stop ppl from seeing things that not there^^

Tekway/Hantek


Hameg

[AndyC_772]

and you must be an expert, are you? No, don't answer this, simply read what i wrote i learn from it.

Likewise...

When comparing noise levels, you have to be sure to compare like-for-like in terns of noise bandwidth. Most TDS700 series scopes are 500 MHz, so they're bound to show more noise on any given signal than a 70-200 MHz scope. If you have a TDS700 then you know you can filter the bandwidth down to 50 or 200 MHz and observe the difference. Have you tried this?

If you're interested in comparing the noise levels between the two, measuring the calibrator signal is pointless anyway. A calibrator signal is non-critical; the quality of this signal is quite incidental to the quality of the scope overall - and if you want to measure the noise level of the scope's front end amplifier and ADC stage, you can (and should) do so with it GND coupled or shorted out at the BNC socket.

So let's compare the "cheap bleh chinese scope" with U.S. made 18k+ USD scope, TDS700 series.

Invalid comparison - the noise bandwidths aren't the same. The Tek is bound to show more noise than the cheap scope unless it's set to the same bandwidth. If it doesn't, then the cheap scope has a front end which is inherently noisier.

and here frequency response, it look flat enough, not only for "cheap bleh chinese scope":

That doesn't look particularly flat to me - but even so, it's a very difficult measurement to take correctly. Do you have a function generator with an accurately calibrated, flat output, and an excellent quality 50 Ohm coaxial cable linking it to the scope? Was the scope set to 50 Ohm input or properly terminated some other way at the BNC input? If not you'll get standing waves set up in the cable due to the reflection at the ends, which will depend on the quality of termination and will change with cable length. The measurement you've made is just as easily explained by poor measurement technique as it is by the scope not having a flat response. Try some experiments with different settings and different cable lengths, you'll see what I mean.

You have to understand few things about DSOs:

1 . the noise is everywhere, when you use long ground leads your scope will pickup even noise
from Argard spacesheeps flying light years away from here.

This is a common misconception, a long ground lead doesn't result in a scope "picking up" noise to any significant extent. It does, however, result in noise which already exists on the GND of the source being probed (with respect to the ground at the scope input) appearing superimposed on the wanted signal.

It looks from your final images as though this scope doesn't actually have a proper intensity graded trace after all. Shame. I had it down as a reasonable model let down by a poor UI, but it seems it's not actually as capable as I thought.

[tinhead]

and you must be an expert, are you? No, don't answer this, simply read what i wrote i learn from it.

Likewise...

aha, is he your gay friend or what? Seriously, he can speak for himself, and you should really stop using "magic ball"

When comparing noise levels, you have to be sure to compare like-for-like in terns of noise bandwidth. Most TDS700 series scopes are 500 MHz, so they're bound to show more noise on any given signal than a 70-200 MHz scope. If you have a TDS700 then you know you can filter the bandwidth down to 50 or 200 MHz and observe the difference. Have you tried this?

      

Andy, of course i've checked before i posted anything. But hey, here a picture, extra made for you:

If you're interested in comparing the noise levels between the two, measuring the calibrator signal is pointless anyway. A calibrator signal is non-critical;

and did i ever said "it is important"? nvr0hk asked about and he got an answer.

Maybe you should simply read what i wrote:

And I still think that is a pretty lousy calibration signal fom the tekway...

no doubt, but for probe calibration good enough ^^ . It think it could be easy modified, but well, for what? That's only cal signal.

the quality of this signal is quite incidental to the quality of the scope overall - and if you want to measure the noise level of the scope's front end amplifier and ADC stage, you can (and should) do so with it GND coupled or shorted out at the BNC socket.

Invalid comparison - the noise bandwidths aren't the same. The Tek is bound to show more noise than the cheap scope unless it's set to the same bandwidth. If it doesn't, then the cheap scope has a front end which is inherently noisier.

Andy,

stop using "magic ball", to have an opinion about something you should buy or loan it and test it.
You should not even trust on measurments done by others. But hey, i've made a schematic of these Tekway/Hantek DSOs

https://www.eevblog.com/forum/chat/hantek-tekway-dso-hack-get-200mhz-bw-for-free/?action=dlattach;attach=12233

so you can download it, analyze and tell me what you think^^.
I personally don't really care that much about the quality of Tekway's frontend, designed to work properly up to 500MHz,
used by Rigol in their 300MHz DSOs, so i assume it was properly tested.

For my old eyes the noise level of the frontend, the parts used and the build quality is more than suficient and can
beat many other scopes. There are other things i don't like, simply check my thread (i should call it book)

https://www.eevblog.com/forum/chat/hantek-tekway-dso-hack-get-200mhz-bw-for-free/

That doesn't look particularly flat to me - but even so, it's a very difficult measurement to take correctly. Do you have a function generator with an accurately calibrated, flat output, and an excellent quality 50 Ohm coaxial cable linking it to the scope? Was the scope set to 50 Ohm input or properly terminated some other way at the BNC input? If not you'll get standing waves set up in the cable due to the reflection at the ends, which will depend on the quality of termination and will change with cable length.

i call ± 0.4dBm as good enough, especially due the fact that my signal gen (calibrated R&S SMX)
can have ±0.25dBm deviations between 10MHz and 250MHz.

Of course it was properly terminated, and i definitely not using cheap china or what so ever crap terminators, cables,
splitters, attenuators, etc. It is not that they can't build things, sure they can, but then there is no price difference
to good known products, so no need to "support" them here. And all these cheap things on ebay, they simply useless.

The measurement you've made is just as easily explained by poor measurement technique as it is by the scope not having a flat response. Try some experiments with different settings and different cable lengths, you'll see what I mean.

I'm sure i know how to measure such simple thing. What i know as well, if i would make mistake, i would tell it.

This is a common misconception, a long ground lead doesn't result in a scope "picking up" noise to any significant extent. It does, however, result in noise which already exists on the GND of the source being probed

i would not sign this, the noise picked up already by the common ground is one thing, the extra noise picked up by
"ground lead antenna" is extra thing. If there would be no difference and extra noise, a shorter lead would not change anything.

It looks from your final images as though this scope doesn't actually have a proper intensity graded trace after all. Shame. I had it down as a reasonable model let down by a poor UI, but it seems it's not actually as capable as I thought.

you got that wrong, it does have intensity graded trace.







The point here was that a "static" pixel (or resulting line), when the fw is using 2pix grading, is having only one color for both pixels - sure it is static. Hameg however is here using two colors (so far i can see from other ppl picutres), which makes the line thiner for human eyes.

I had it down as a reasonable model let down by a poor UI, but it seems it's not actually as capable as I thought.

To be taken seriously, and not just dismissed as yet another not-quite-finished Chinese product (regardless of where it's actually designed and built), what it really needs is a UI overhaul from someone with specialist experience in this area and some properly decent graphic design skills. It's an area in which the established quality manufacturers (I'm thinking Agilent and Tektronix here) are streets ahead, and it makes a huge difference.

Yeah, they did it, on chinese way ... The UI of their previous Tekway model was 1:1 copy of TEK TDS2000 UI:





The current model is however using slightly modified version, many things are still "stolen" from TDS2000 (icons, menus, messages) , some other from DPO2000 (dual window, how FFT will be displayed). I don't know, for someone who always worked with TEK only i don't see here bad things,
i would said i like it.

The only really annoying thing is the color UI color palette, TEK blue and black(gray) are ok, but yellow, green and pink are
for me personally "too much of china engineering" (or maybe i'm too old or not gay enough)

[rf-loop]

You have to understand few things about DSOs:

1 . the noise is everywhere, when you use long ground leads your scope will pickup even noise
from Argard spacesheeps flying light years away from here.

This is a common misconception, a long ground lead doesn't result in a scope "picking up" noise to any significant extent. It does, however, result in noise which already exists on the GND of the source being probed (with respect to the ground at the scope input) appearing superimposed on the wanted signal.

Are you kidding?
I'm so lazy I do not show images here about  tests - this is so trivial basic fundamental.
Just connect probe long GND wire to probe tip and look what you see in  noisy (and becouse this "looks like kidding" I need note that I do not mean noise what you hear with your ears)  enviroment.

But yes you are also partially right. Scope do not pick up... it is this antenna what pick up.

Lets take something what may help to imagine this.

Take your AVOmeter and measure oscilloscope probe 15cm lenght GND wire resistance. Yes your meter show nearly zero ohm. This is its resistance. It works with DC and in audio frequencies it have not big effect other than its resistance.
But example for noise it is not at all zero resistance. It is roughly around 200nH inductance.
If look reactance map... example 100MHz: roughly 125 ohm (in practice situation is different and if go more deep details it go very complex - yes just this short GND wire... )

What is "long" GND wire in your comment... 10mm or 10cm or 50cm

10mm "long wire" reactance with 100MHz is around4 ohm
100mm "long wire" around 70ohm
500mm "long wire" around 460ohm
But my AVOmeter needle show "zero"

With 500MHz this 100mm GND wire reactance is around 360 ohm.

Btw, this 15cm GND wire is antenna... all voltages between this  this antenna  ends are injected to system..  connect your probe GND wire to center tip and go with it near your laptop or near to energy saving lamp... what you see. Your probe is short circuited? If it is really short circuited why you see this noise. Ok lets do other test. Connect probe GND area what is just around tip directly to tip  with as low reactance as possible. Try pick up this noise agen..   and now you tell lenght of probe GND do not mean.

Do you know how 10cm 10mm diameter copper "wire" may have voltage potential differences between its ends without connecting it to nowhere... how it is possible becouse my AVOmeter show its resistance is "zero"  ...
But yes this straight 10mm diameter 100mm long copper  wire is also over 50nH inductance..
With 2GHz  nearly 700 ohm...

2.4cm long 1cm diameter "wire" is nice around 50ohm  when use it somewhere around 1.3GHz.

Then someone come and tell GND wire lenght do not mean...

Please go to enviroment where is some RF / EMI noise and do your lesson number 1 with noise in measurements.


Also here in forum we have seen after time to time several examples when peoples "wondering" they have some "special noise issue"  in the scope screen...even if they connect probe tip and GND together.  Partially (not always)  these are just from misunderstanding nearly all things but eyes blinking with noisy display...  perhaps they have learned just this same bullshit what you try teach to us.

With this calculator it is nice to look around what is what...

[nvr0hk]

Thank you to all, yes to all the forum's members who takes their time to answer me and who argued with their knowledge to show me what is wrong and how to short it out!

My Thanks to AndyC_772, amyk, grumpydoc, Bored@Work, marshallh, PA4TIM, tinhead and rf-loop! 

Well, you know all which version of DSO I purchased and I already read Hantek - Tekway - DSO hack - get 200MHz bw for free of tinhead (Thank you to you for this great thread), but this unit doesn't require any hack.

My question was based on this thread Rigol DS1052E nasty surprise!, and this asked me if my unit is not affected by this type of problem...

Yours answers opens more questions, but unfortunatly, I was using my smartphone as an usb stick, with pushing "SAVE TO USB" button, which now crash frequently (now one more reboot with flushing all my previous settings) or doesn't save any more any picture  on it... 

Even more worse, if I do this button sequence:

AUTO SET
CH1 MENU
Coupling "GND"

or

CH1 MENU
Coupling "GND"
CH2 MENU
Coupling "GND"

  then after few seconds, reboot! 

  Now, this scope is even rebooting if I repeat the previous operation to repeat the setting in my first post...

  I am at the point to find what's wrong even before reading Oscilloscope training class (long) due to this instabilities.

[tinhead]

but this unit doesn't require any hack.

yeah, sometimes a "real" 200MHz were sold as 60 or 100 models, but here i might have an other idea ...

Even more worse, if I do this button sequence:

AUTO SET
CH1 MENU
Coupling "GND"

or

CH1 MENU
Coupling "GND"
CH2 MENU
Coupling "GND"

  then after few seconds, reboot! 

  Now, this scope is even rebooting if I repeat the previous operation to repeat the setting in my first post...

  I am at the point to find what's wrong even before reading Oscilloscope training class (long) due to this instabilities.

... there is nothing like that, something is here wrong (this is maybe "already 200MHz enabled ... amybe someone played already)
In principle no matter what fw revision is installed, you could re-install the latest version from Hantek website.
The only point i'm worry is the reboot, so try first to pusf "deafult settings" button, after that reboot it and try with
latest firmware update.

Tell me what fw version is on the unit now?

[nvr0hk]

The only point i'm worry is the reboot, so try first to pusf "deafult settings" button, after that reboot it and try with latest firmware update.

DEFAULT SETUP --> Freeze and 30-60 seconds reboot
DEFAULT SETUP --> stable
...
DEFAULT SETUP --> Freeze and 30-60 seconds reboot

Tell me what fw version is on the unit now?

UTILITY
2.06.3(121208.3)

and less than 5 minutes reboot...

now this scope is frozen (oh sorry freeze > 2 minutes), and this the first day is saw this such behaviour (after a near week)... 

and try with latest firmware update.

I don't have any proper usb key under vfat...

[tinhead]

what OS are you running ? You could install this tool

http://www.dreisiebner.at/dso-usb-tool/

and then execute

rm /param/sav/run*

in the "Shell (F2)" tab. But check first with ls or the predefined /bin/busybox --help
command the communication with DSO. Depends on OS, you can use original or LibUSB or only LibUSB as drivers.

The rm /param/sav/run* will delete the DSO setting file, you will have to then to reboot DSO and check again if
now the firmware is rebooting itself after few seconds. If still the case, you can think about warranty case.

[nvr0hk]

what OS are you running ?

Ubuntu 12.10 armhf

If still the case, you can think about warranty case.

Yes, the seller asked me to send it back, but the price is around 230 euros (near 2/3 of it's initial price), which isn't an option for me... I am waiting an answer from Hantek through the seller...

[PA4TIM]

That is why I buy local if possible. There seemed to be some possible problem with my type of Hameg,. Hameg first sended a new originsl box so I could pack it, then next day collected the scope and i got it back upgraded calibrated and modified a few days later at no cost !

It can be cheap to buy from asia or far away but if there is a problem you lose a lot of money ( and read on several forums, you are not alone, DOA's do exist and are not limmited to local buyers)

[tinhead]

right, DOA is always possible, especially when you combine BGA and China.

Yes, the seller asked me to send it back, but the price is around 230 euros (near 2/3 of it's initial price),
which isn't an option for me... I am waiting an answer from Hantek through the seller...

and i can tell you already Hantek's answer - "send back to seller". This is because the seller is making more money than Hantek,
so you can assume they don't have any room for DOA handling. ure, there is warranty, but shippment must be paid by enduser.

So did you tried to run the software? If you don't (or did't worked for you), you can still try to open the enclosure, connect
TTL UART<->USB converter between the internal UART port (3.3V UART) to your PC, connect to DSOs shell,
kill dsod process (this is the watchdog rebooting your DSO) and dso.exe, then go to /param/sav/ dir and delete the run1kb* file.
After this you can run from root /dso.exe to see if the DSO is working properly and not rebooting anymore.

I hope for you this will fix the problem. In principle the dsod watchdog should reboot DSO when something wrong,
maybe simple bad batch, someone else had few days ago similar problem and fixed it over UART.
In principle the dsod is also deleting the run1kb* file, so maybe simply bad/locked file and watchdog can't delete it.

The really good thing is, these DSO are using linux, DSO apps are known, all (oh well, almost) manufacturer secrets known.
I have not yet finalized hw1007 schematic, but the one i posted (year ago?) from hw0 is very similar, so it can be used
to fix hw1007 DSOs.

More inormations here:

https://www.eevblog.com/forum/chat/hantek-tekway-dso-hack-get-200mhz-bw-for-free/

[nvr0hk]

tinhead, thank you for your help!

So did you tried to run the software?

until now, no, I prefer to use the serial!

[nvr0hk]

I hope for you this will fix the problem.

Sure, opened it, I saw too much soldering dust under the PCB... A first visual inspection reveal bad soldering joint (power connector J905 pin3, KIA78 RO5PI 947  U908, C913 10V 100uF, near C912, Front USB J902 left ground leg, EXT TRIG J300 left ground leg, C943 470uF 25V ground leg)! 

I have not yet finalized hw1007 schematic, but the one i posted (year ago?) from hw0 is very similar, so it can be used
to fix hw1007 DSOs.

Yes, MB inscription:  DST1000B Serial MB Ver1.00.7 2011/04/27

[tinhead]

I hope for you this will fix the problem.

Sure, opened it, I saw too much soldering dust under the PCB... A first visual inspection reveal bad soldering joint (power connector J905 pin3, KIA78 RO5PI 947  U908, C913 10V 100uF, near C912, Front USB J902 left ground leg, EXT TRIG J300 left ground leg, C943 470uF 25V ground leg)! 

oh dear, if there is something i really hate, then a on sunday produced device, by someone who never learned how to solder (at that point i alw<s hope it was at least a young good looking girl or boy). This is now paint inf the ass, but i think it will be still cheaper than sending it back. This is why i always recomend to buy things local, not matter where they originaly produced.

[nvr0hk]

oh dear, if there is something i really hate, then a on sunday produced device, by someone who never learned how to solder (at that point i alw<s hope it was at least a young good looking girl or boy).

As what I am seeing, I don't think this is the most harmfull, all the garbage of soldering (small soldering ball of around 0.2mm and metal scrap from holes in frame) and as I saw, the MB and Keyboard has not been washed (on the buzzer there is still the "HXD REMOVE SEAL AFTER WASHING" stick!!!) which is definitely the wrong point. I am starting to understand where is come from all of this noise. 

Then, what can I do to clean up the thin layer of grease on the PCBs?

[tinhead]

I am starting to understand where is come from all of this noise. 

noise is not coming from solder residue.

You should check the 2 power rails (white) sockets, they are in 99% of all "unknowwn" issues the source of problems - when
the current flow is not satisfiying the mainboard needs, linux or any app running on linux will fuck up.

When you wish to wash the pcb use IPA.

Did you already tested the UART solution?

[nvr0hk]

When you wish to wash the pcb use IPA.

Thanks, but I don't have it at hand...

Did you already tested the UART solution?

no, I have already an USB2UART&BT module (based on SILABS (?) CP2102 from Dealextreme) but, until now, I don't fetch in your thread the scheme to find where to connect TXD/RXD and GND on the motherboard... 

I just cleaned the PCB keyboard but the result is not as clean as I expect.

[tinhead]

no, I have already an USB2UART&BT module (based on SILABS (?) CP2102 from Dealextreme) but, until now, I don't fetch in your thread the scheme to find where to connect TXD/RXD and GND on the motherboard... 

ehm, almost all you need is on the very first thread page, first and second post.

I've made the picture a bit bigger, you should see it immediately

[nvr0hk]

ehm, almost all you need is on the very first thread page, first and second post.

second post, here

I've made the picture a bit bigger, you should see it immediately

not exactly, I was reading this version.
Otherwise, I have found 3 male-male wires for soldering them on the PCB.

[nvr0hk]

rm /param/sav/run*

there is no /param/sav/run* file.

The rm /param/sav/run* will delete the DSO setting file, you will have to then to reboot DSO and check again if
now the firmware is rebooting itself after few seconds. If still the case, you can think about warranty case.

If try "AUTO SET", in console I get 'Killed' and after a couple of second the watchdog do 'The system is going down NOW!'
then if I do pkill dsod, and I run again ./dso.exe, the first time I got 'Killed', and below what's happened:

Code: [Select]

[root@Tekway-dso /]# ./dso.exe
sh: can't create /ker_rel_tmp_file: Cannot allocate memory
mmap start addr:0x40373000, phy addr :0x33d00000, mmap size: 0x5e000
Segmentation fault


[tinhead]

looks bad ... anyway, let's try following

check with df -h how much space is available, not that we running out of space due what so ever.

Kill all dso.exe processes, kill all dsod.
Delete /dso.exe, all files in/OurLanguages/
Delete the /dsod (if exists) or /dso/app/dsod (if exists)
delete from /param/sav/ everything but not the chk1kb* file

Download this here

https://hotfile.com/dl/191684044/9ebada9/2.06.3_130114.0.ZIP.html

unzip the dso.exe to / of the DSO, then the OurLanguages/English.lan to /OurLanguages/ folder of the DSO.

chmod 777 /dso.exe

power off DSO, power it on again (to ensure that all reset vectors are properly initalized, a soft reboot is not good enough)

and hope the /dso.exe is running now

If not, rename it to /dso.back, power off DSO, power on again, logon to shell, rename /dso.back to /dso.exe
and run it as /dso.exe

Now you should see some messages, they could maybe give us the missing information we looking for.

[nvr0hk]

check with df -h how much space is available, not that we running out of space due what so ever.

It seems you are right:

Code: [Select]

[root@Tekway-dso /]# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root                61.7M     61.7M         0 100% /
none                     30.0M         0     30.0M   0% /tmp
none                     30.0M         0     30.0M   0% /var
[root@Tekway-dso /]# mount
rootfs on / type rootfs (rw)
/dev/root on / type yaffs (rw)
none on /dev type devfs (rw)
none on /proc type proc (rw,nodiratime)
none on /tmp type tmpfs (rw)
none on /var type tmpfs (rw)
[root@Tekway-dso /]# ./dso.exe &
[root@Tekway-dso /]# uname: standard output: No space left on device
mmap start addr:0x40373000, phy addr :0x33d00000, mmap size: 0x5e000
I got "No space left on device" when I tried to insert my smartphone as an usb stick.
Then, I found why and what's happened:

Code: [Select]

[root@Tekway-dso /]# ls -al /mnt
total 24196
drwxr-xr-x    1 root     root           512 Dec 16  2011 .
drwxr-xr-x    1 root     root           512 May  9  2012 ..
drwxr-xr-x    1 root     root           512 Jan 24  2013 hantek3_1
drwxr-xr-x    1 root     root           512 Jan 24  2013 hantek3_2
drwxr-xr-x    1 root     root           512 Jan 24  2013 hantek3_3
drwxr-xr-x    1 root     root           512 Jan 29  2013 hantek3_4
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek4_1
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek4_10
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek4_11
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek4_2
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek4_3
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek4_4
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek4_5
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek4_6
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek4_7
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek4_8
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek4_9
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek5_1
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek5_2
drwxr-xr-x    1 root     root           512 Jan 25  2013 hantek5_3
drwxr-xr-x    1 root     root           512 Jan 28  2013 hantek7_1
drwxr-xr-x    1 root     root           512 Jan 29  2013 hantek7_2
drwxr-xr-x    1 root     root           512 Jan 29  2013 hantek9_1
-rw-r--r--    1 root     root       8200048 Jan 24  2013 hantekRecord30.rec
-rw-r--r--    1 root     root       8200048 Jan 24  2013 hantekRecord31.rec
-rw-r--r--    1 root     root        164048 Jan 24  2013 hantekRecord32.rec
-rw-r--r--    1 root     root       8200048 Jan 24  2013 hantekRecord40.rec
[root@Tekway-dso /]# du -sh /mnt
44.3M   /mnt
Now, I understand what's wrong, the mount operation failed when I tried to save all the screenshot with my smartphone, and the dso.exe continue blindly to save them under /mnt which, in this case, is /... 

More soon...

[nvr0hk]

back to the basics of this subject, signal (this a measurement tool) with Reference signal injected in CH1 and a base transistor of a joule thief in CH2: