Author Topic: EEVblog #487 - Tekway DST1102B Oscilloscope Review  (Read 45830 times)

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Offline bilko

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #25 on: June 25, 2013, 10:39:07 pm »

Why is it that they can't seem to get the UI and the functionality all the way at times?
They get like 90% of the way there then fall on their face.

Because in any project it costs 10% to get 90% of the way there and another 90% to get the last 10%.
Most Chinese manufacturer's avoid the last 10%
 

Offline dexters_lab

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #26 on: June 25, 2013, 10:40:47 pm »
 :( my rigol is "ancient"
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Offline cloudscapes

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #27 on: June 25, 2013, 11:23:55 pm »
I'm not getting much overshoot on high frequency square waves. Then again I'm using the Hantek (not Tekway) and it's the MSO version with logic. Maybe there are differences to the front-end between Hantek and Tekway, or maybe because the MSO line is newer? (I actually don't know)
 

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #28 on: June 26, 2013, 03:59:47 am »
ugh... it's ugly. jebus. I mean, the DS1000 series aren't the most attractive things in the world, but damn... the fonts just look terrible and nobs, etc. ugh.

i don't mind its looks actually. The OWON I found ugly but I don't mind the Tekway.
 

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #29 on: June 26, 2013, 04:06:19 am »
Ok, so it seems I'm getting my arse chewed out for some operational errors/oversights I made in this video, and rightly so of course.
These things can happen because of the first impressions nature, but that's no real excuse.
I want to add some annotations, so if anyone can point out a time in the video and error I made, I'll correct it.

However, my first impressions conclusions stand.
The scope had poor pulse response, poor trigger jitter/stability, it's slow, and the firmware locked up.
If it turns out that my unit was faulty for some reason, then so be be it. But I can only review and comment on the facts I saw and presented in the video for the unit I had.
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #30 on: June 26, 2013, 07:27:36 am »
However, my first impressions conclusions stand.

and that's ok, it is your first impression and it should not be changed by any comments etc.


The scope had poor pulse response,

yes, the scope you tested have have pure response, it might be faulty unit, manipulated unit
or one of the units with bad response (see my first comment in this thread)


poor trigger jitter/stability,

yes, the scope you tested is having 83EB FPGA design which sucks. The explanation and possible
solution is in my fist comment in this thread, but this does nt change anything on first impression.


it's slow

yes, it is slow as hell, as i mentioned in my first reply in theis thread only 4k and 40k are useful for
daily work, the 512k/1M/2M are for one off measurments. Actually if someone worked with older TEK
DSO with lot of memory then there would be no change^^


it's slow

and something like XY-mode with 512k memory and dual window is actually an bug, there is no other name
for waiting 5 seconds to get an key response. I have no idea WHY this is sill enabled.


and the firmware locked up.

yes it does, this could be fw revision related


If it turns out that my unit was faulty for some reason, then so be be it. But I can only review and comment on the facts I saw and presented in the video for the unit I had.

you know what, i could be the person protecting something here, but i don't see a reason to protect anything.
The first impression is first impression, when someone got faulty or "monday unit" it still does not matter, the first
impression stays the same. There should be no "monday units" nor faulty if QC would be properly working.

Same for firmware bugs, sure when some not fixed yet then they not fixed, but in principle manufacturer (or at least dealer)
should have installed latest firmware to avoid some revision issues, but that was not the case for your unit.
Does it have any influence on your impression? not at all, you got what you got any saw what you saw, and that's ok.

In my opinion you don't have to add any annotations (of course some fixing RTFM are always good). This is test gear and it have to work directy, there should be no locks or bugs, no user/community or what so ever "aftersale solutions". People producing test gears have to understand that they have to be reliable, shit, imagine a car which stops reacting on anything when you try to accelerate too fast when it's cold (i remember i got such E-class MB few years ago, THAT was a dangerous crap) or imagine someone on the gas station (which can be compared to forum) tells you "hey, you could use ferrari engine, then your car would drive properly and not jump around" Your answer would be probably "F* what?" So no, even if there are user made solutions to fix x or y and a and b is RTFM and .... it still does not change anything on first impression!
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Offline lemon

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #31 on: June 26, 2013, 12:10:10 pm »
Probably this scope is faulty!

But I have a concern about how the scopes demonstrate the square pulse. And the test done with the same signal generatoror and the same 50 Ohm resistor.
OK, this Tekway unit has a lot of ringing and over or undershooting.
Rigol's scope has a identical pattern without any over or under-shooting.
Agilent and Owon has a almost identical patterns that differs than Rigols.

Wich pattern is true, Agillent/Owon or Rigol. For me the pattern of Rigols it seems to have a lot of smoothness.
What is your opinion for this differences?
 

Offline Hydrawerk

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #32 on: June 26, 2013, 12:28:46 pm »
Dave, why did the distributor send you a faulty scope? That's strange.
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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #33 on: June 26, 2013, 12:35:06 pm »
Dave, why did the distributor send you a faulty scope? That's strange.

I have received no notification that this was a faulty or suspect unit at all. So I can only presume it is a good and typical performance unit unless I hear otherwise.

Tinhead is saying there are several hardware versions that have different performance?
 

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #34 on: June 26, 2013, 12:38:52 pm »
Probably this scope is faulty!
But I have a concern about how the scopes demonstrate the square pulse. And the test done with the same signal generatoror and the same 50 Ohm resistor.
OK, this Tekway unit has a lot of ringing and over or undershooting.
Rigol's scope has a identical pattern without any over or under-shooting.
Agilent and Owon has a almost identical patterns that differs than Rigols.
Wich pattern is true, Agillent/Owon or Rigol. For me the pattern of Rigols it seems to have a lot of smoothness.
What is your opinion for this differences?

Unless the input signal is perfectly terminated etc the bandwidth of the scope bandwith will determine what high frequency content (overshoot/undershoot is an example) is shown.
That is why the 500MHz Agilent differs and shows that higher frequency content.
Of course, that assumes that all scopes have the same rolloff response, which they should ordinarily do to a reasonable order.
In theory the 100MHz Rigol 1052E and Tekway should have had the same "rounded" response that lacked that high frequency content. The Rigol 1052E is the response you would expect, with the DS2000 showing a bit more content, and the Agilent and OWON the most.
From this it is clear that the Tekway has a major problem. What that problem is unclear.
« Last Edit: June 26, 2013, 12:53:01 pm by EEVblog »
 

Offline Hydrawerk

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #35 on: June 26, 2013, 12:39:15 pm »
The distributor is weird.  :--
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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #36 on: June 26, 2013, 12:54:51 pm »
The distributor is weird.  :--

Why?
They had every reason to believe that this was a good production unit, it's not their fault.
 
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Offline Rasz

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #37 on: June 26, 2013, 01:25:05 pm »
The distributor is weird.  :--

That distributor is honest. You can tell he doesnt cheat the "Dave test". After all he will get a lot of customers when he finally scores the big one and gets Daves thumbs up on some product :) Rigol got huge bump in sales thanks to Dave, and that was before eevBlog channel got popular.
 I worked for PC parts distributor over 10 years ago (third in sales in my country, sole distributor of some big brands at the time etc) and it was common for sales/PR people to come down to the service area basement and tell us to find a "perfect unit" because some IT Paper had a hardware shootout. All of a sudden shitty brand CRT monitor/CDrom was scoring perfect marks.
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Offline lemon

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #38 on: June 26, 2013, 01:27:44 pm »
At the "Hantek-Tekway-DSO cack - get 200M..." there is a reference (#1807) of member "rf-loop" about faulty Chinese products.
https://www.eevblog.com/forum/testgear/hantek-tekway-dso-hack-get-200mhz-bw-for-free/1800/

He said:
...
(I have always made "pre-ageing" and tests for every single scope I have sell.
What ever model or brand it is. Also other new equipments. All go to burn in tests before accepted for sell. failed units stop to my barrier and did not go to end users. This is one reason why I do not so much admire these re-shipper sellers who only receive parcels, get orders and send parcels to end users. But cheapest price win - of course, or is it so...

In this time average was around 50% failed after arrive from factory.

Here one fun sample image.
Signal is around 16MHz quite clean sinewave from medium grade generator HP8657B.

Probably this happens to all Chinesse scopes (Rigol, Owon, Siglent, e.t.c).

David, have you all this scope, or you have returned the Owon and Tekway?
OK, I undertand that the scopes with high BW has a lot of frequency content. The Agilent is 500MHz, the Owon is 300MHz the Rigol 1052 is hacked 100MHz (50MHz) but the other Rigol with 200MHz why seems like other Rigol and not to 300MHz Owon.
Please, if you don't have the Owon and Tekway can you examine the Agilent and Rigol the same frequency with a limited BW?
« Last Edit: June 26, 2013, 01:30:31 pm by lemon »
 

Offline John Coloccia

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #39 on: June 26, 2013, 01:37:08 pm »
Look at time 36:30.  Is that some big DC offset that crept in after the cal?  As an engineer, I really scratch my head and wonder how some of this stuff gets out the door.
 

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #40 on: June 26, 2013, 01:53:08 pm »
David, have you all this scope, or you have returned the Owon and Tekway?

The OWON and Tekway have gone back, I only had them for a day or two.

Quote
OK, I undertand that the scopes with high BW has a lot of frequency content. The Agilent is 500MHz, the Owon is 300MHz the Rigol 1052 is hacked 100MHz (50MHz) but the other Rigol with 200MHz why seems like other Rigol and not to 300MHz Owon.

Because it's 200MHz and not 300MHz. Cutting out a harmonic or two can make all the difference.
 

Offline Winston

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #41 on: June 26, 2013, 03:54:40 pm »
nah, i dont want to take my  Voltcraft apart, it still has warranty i think.
Does it have a date of manufacture on it somewhere?
 

Offline Winston

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #42 on: June 26, 2013, 04:02:54 pm »
At the "Hantek-Tekway-DSO cack - get 200M..." there is a reference (#1807) of member "rf-loop" about faulty Chinese products.
https://www.eevblog.com/forum/testgear/hantek-tekway-dso-hack-get-200mhz-bw-for-free/1800/

He said:
...
(I have always made "pre-ageing" and tests for every single scope I have sell.
What ever model or brand it is. Also other new equipments. All go to burn in tests before accepted for sell. failed units stop to my barrier and did not go to end users. This is one reason why I do not so much admire these re-shipper sellers who only receive parcels, get orders and send parcels to end users. But cheapest price win - of course, or is it so...

In this time average was around 50% failed after arrive from factory.

Here one fun sample image.
Signal is around 16MHz quite clean sinewave from medium grade generator HP8657B.

Probably this happens to all Chinesse scopes (Rigol, Owon, Siglent, e.t.c).

David, have you all this scope, or you have returned the Owon and Tekway?
OK, I undertand that the scopes with high BW has a lot of frequency content. The Agilent is 500MHz, the Owon is 300MHz the Rigol 1052 is hacked 100MHz (50MHz) but the other Rigol with 200MHz why seems like other Rigol and not to 300MHz Owon.
Please, if you don't have the Owon and Tekway can you examine the Agilent and Rigol the same frequency with a limited BW?

How did you miss this part of that post in big bold red letters?:

And note: This is from APRIL 2011

This is history. This must not connect with today Hantek equipments.

This is probably a demonstration of the problem with the catastrophic hardware revision that Hantek did in 2011 as described elsewhere by tinhead.

 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #43 on: June 26, 2013, 04:06:20 pm »
At the "Hantek-Tekway-DSO cack - get 200M..." there is a reference (#1807) of member "rf-loop" about faulty Chinese products.
NO, this was in 2011, affecetd was hw1005, we now at hw1007


The Agilent is 500MHz, the Owon is 300MHz the Rigol 1052 is hacked 100MHz (50MHz) but the other Rigol
with 200MHz why seems like other Rigol and not to 300MHz Owon.

it is not only the 200MHz bw on Rigol DS2202 (Actually 250), it is how the frontend has been developed.
There is a JFET/NPN combination, very similar to what in DS1000E, with good flat response. However Rigol
decided to have more gaussian response here, the resulting waveform shows a littebit less overshoot.

OK, I undertand that the scopes with high BW has a lot of frequency content.

i show differences between bandwidth on exact the same DSO (only the software based filter set to one of the bw below)
a 60MHz Tekway


a 100MHz Tekway


a 200MHz Tekway


and 350MHz Tekway


One can ask "where i got the 350MHz", well, the filter can be set to everything between 60 and 900MHz,
of course with 1GS/s it does not make sense to do anything above 400MHz.

The 350MHz results from pulse measurments, following square signal


has been applied and measured. I use 500MHz probes, so the real frontend rise time is
sqr((1.250ns)²-(0.7ns)²), so 1.036ns. I know that this frontend have flat response so i should
use 0.4 factor to calculate bw (so 386MHz), but i prefer to use mid value (0.4 + 0.34 /2), that ~ 350MHz.


« Last Edit: June 26, 2013, 04:09:41 pm by tinhead »
I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
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Offline Winston

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #44 on: June 26, 2013, 04:08:05 pm »
Probably this scope is faulty!
But I have a concern about how the scopes demonstrate the square pulse. And the test done with the same signal generatoror and the same 50 Ohm resistor.
OK, this Tekway unit has a lot of ringing and over or undershooting.
Rigol's scope has a identical pattern without any over or under-shooting.
Agilent and Owon has a almost identical patterns that differs than Rigols.
Wich pattern is true, Agillent/Owon or Rigol. For me the pattern of Rigols it seems to have a lot of smoothness.
What is your opinion for this differences?

Unless the input signal is perfectly terminated etc the bandwidth of the scope bandwith will determine what high frequency content (overshoot/undershoot is an example) is shown.
That is why the 500MHz Agilent differs and shows that higher frequency content.
Of course, that assumes that all scopes have the same rolloff response, which they should ordinarily do to a reasonable order.
In theory the 100MHz Rigol 1052E and Tekway should have had the same "rounded" response that lacked that high frequency content. The Rigol 1052E is the response you would expect, with the DS2000 showing a bit more content, and the Agilent and OWON the most.
From this it is clear that the Tekway has a major problem. What that problem is unclear.

Possibly due to this as pointed out by tinhead in an earlier post in this thread?:

- the frontend story  For a long time i was fighting with ppl in German forum, i was wondering why they getting crap waveforms on their scopes where my was looking much better. Long story short said - for (unknown to me) reason Tekway/Hantek changed some resistors in their frontend. Btw, this is the same frontend what Rigol is using in DS1000E (that affected part exists even on DS2000). Of course Siglent/ATTEN are using exact the same frontend, hehe. Anyway, i and some other ppl made lot of measurments and simulations, finally we have working combination, it is even better that original DS1000E and even better than my old Tekway. There is no need to change anything on org. DSOs, but on hacked (or all what need to work over 100MHz, this is why this never was an issue on DS1000E). All the necessary information about is in the Tekway hack thread: https://www.eevblog.com/forum/testgear/hantek-tekway-dso-hack-get-200mhz-bw-for-free/msg212054/#msg212054
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #45 on: June 26, 2013, 04:13:30 pm »
exact!

So yes, Dave tested DSO where S/N on outside case was from hw1005, but on mainbaord from hw1007, from let me guess Nov 2012^^ I didn't saw 2ns/DIV timebase, so for sure 200MHz bw was not enabled, but it is actually enough to manipulate the bw filter (like in my posting just above, ups, on bottom of page 3 here). When Daves DSO have mainboard from Nov 2012, then it was for sure affected with bad resistors (well, they not bad, they only bad if bw is higher than 100MHz, hehe). The amount of ringing/overshoot is actually typical for "hacked" DSO with not proper components in frontend, but as i said, bandwidth does not need to be set by model number, it can be as well set with a special file to what so ever (don't forget Nyquist).

This is response from original 200MHz Tekway with not affected mainboard (RG174 and 50R terminated)


and here the same signal measured on TDS754A


here the same signal however measured with HF512 500MHz passive probes and original not affected 200MHz Tekway


and here with TDS754A and 1GHz active probes



So once again, originaly a 200MHz DSO was having already good response, this has been changed for some unknown reason (i assume f* cost savings) end of 2011 and was like that until i don't know, maybe even today. My last mainboard was from Jan 2013 and it was still wrong, however, other people with newer DSOs reported no issues, so probably Tekway/Hantek changed it back.

The pictures above are taken on unmodified Tekway, the picture here is from affected unit (and hacked to 200MHz, again, not hacked no problem at all, but hacked is simply crap response), so you can see the ringing and overshoot:


isn't that like on Dave's video? i would say yes, it is.


such unit (and even the original working DSOs!) can be however improved to have much besser response,
here RG174 and 50R terminated


and with HF512 500MHz passive probe:


« Last Edit: June 26, 2013, 04:49:40 pm by tinhead »
I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
I want to reach out with something other than these prehensile paws and feel the solar wind of a supernova flowing over me.
 

Offline Winston

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #46 on: June 26, 2013, 04:25:04 pm »
I also find it interesting that the reviewed Tekway DST1102B had no fan while the mainboard identical Hantek DSO5102B apparently does:

http://www.circuitsathome.com/measurements/hantek-dso5000-series-oscilloscope-modifications-part-2-reducing-fan-noise

Could this mean that Tekway has found that the fan is not really needed in the first place or have they used larger heatsinks for passive cooling?  Is so, that would be great as we'd all prefer silent test equipment.
« Last Edit: June 26, 2013, 04:29:51 pm by Winston »
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #47 on: June 26, 2013, 05:05:46 pm »
Could this mean that Tekway has found that the fan is not really needed in the first place or have they used larger heatsinks for passive cooling?  Is so, that would be great as we'd all prefer silent test equipment.

Tekway told me once that these DSOs can run without fan, in most countries ^^

Later as Hantek started the hw1005 production they recognized that the heat inside the DSO is too high (actually not, but when you overclock ADCs and run FPGA at high speed then you might see more distortion without heatsinks and fan). So they started to populate fan and as well heatins for FPGA and ADCs (originaly there was nothing and it was running well - but hot^^).

The most heat is being produced by the KA378R33 lin reg on PSU PCB. Some people mounted here bigger heatsink, others used dc/dc converter from TI (PTG08080WAZ), the last idea was to use Mircrel HELDO (which is low noise dc/dc and lin reg in one package).

Some simply mounted the fan directly over the KA378R33, replaced the org. 7812 (for fan) by 7805 or 7808 to slow down it a bit.

I'm using right now Mircrel HELDO with 12V Noise Blocker fan, running at 5V, so very slow and very silent. I could use no fan now, but i prefer to not stress components to much. 

For MSO owners: it is important to know that MSO models are consuming more current (0.5W more dissipation on the KA378R33)
I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
I want to reach out with something other than these prehensile paws and feel the solar wind of a supernova flowing over me.
 

Offline Hydrawerk

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #48 on: June 27, 2013, 01:08:32 am »
Oh, Dave's Tekway is really crappy... I want to believe that other Tekway scopes are better.
Amazing machines. https://www.youtube.com/user/denha (It is not me...)
 

Offline John Coloccia

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #49 on: June 27, 2013, 01:34:31 am »
I guess the real question is why would I buy this over a new Rigol, or a used something else.  Seems like a hard sell.  Glad Dave is around to flesh some of this stuff out for people like me that don't get to take these things for a test drive.
 


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