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EEVblog => EEVblog Specific => Topic started by: EEVblog on July 01, 2017, 10:19:03 pm

Title: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: EEVblog on July 01, 2017, 10:19:03 pm
Does the Owon XDS3202A Oscilloscope use a true 14bit converter?

https://www.youtube.com/watch?v=-F4H-zC_i0s (https://www.youtube.com/watch?v=-F4H-zC_i0s)
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: BU508A on July 01, 2017, 10:47:18 pm
Yep. Will not buy this thing. Not in a 1000 years.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: boffin on July 02, 2017, 01:10:45 am
Is it me, or is this a really really bad solder connection...

(https://www.eevblog.com/forum/blog/eevblog-1004-owon-xds3202a-14bit-oscilloscope-teardown/?action=dlattach;attach=328434;image)
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: Monkeh on July 02, 2017, 01:37:46 am
Am I nuts, or is that thing on the front panel above the buttons an IR window?

That multimeter board is just waiting to die of a mild static shock. Or Joe's grill igniter. Flimsy Semiconductor..
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: sergioag on July 02, 2017, 06:09:43 am
Not just the last one. Only the first one would get a "pass" from me. But the last two ones are awful!
(https://www.eevblog.com/forum/blog/eevblog-1004-owon-xds3202a-14bit-oscilloscope-teardown/?action=dlattach;attach=328495)
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: sergioag on July 02, 2017, 06:17:38 am
Also their "cooling" solution is laughable...
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: SNGLinks on July 02, 2017, 06:49:45 am
I wonder if they hope to get better wi-fi by coupling the antenna to the mains?
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: alxpo on July 02, 2017, 08:55:21 am
I'm fascinated. What is the purpose of this exposed gold?
Why gold? Why exposed?
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: bjcuizon on July 02, 2017, 10:40:37 am
Hi Dave, you said that the fuse is missing on the PSU board but I think it is in the IEC connector assy. though.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: EEVblog on July 02, 2017, 12:07:24 pm
Looks like 3 of those joints are dodgy:
https://www.flickr.com/photos/eevblog/35258313980/in/album-72157682836278374/ (https://www.flickr.com/photos/eevblog/35258313980/in/album-72157682836278374/)
Didn't see that on the camcorder LCD.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: EEVblog on July 02, 2017, 12:08:10 pm
I wonder if they hope to get better wi-fi by coupling the antenna to the mains?

That was my first thought. No idea though.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: GameProgrammer79 on July 02, 2017, 12:15:33 pm
I know some one in liliput, company that owns owon (sort of o - we won) :-DD
their research is very small and poor  :=\ no review or quality checks  :=\.. if you get it working .. you are a champ  :palm: but I wonder how they have survived so long. They do have a market and somehow they manage to sell a large number of these poorly designed oscilloscopes 
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: nctnico on July 02, 2017, 04:22:34 pm
Also their "cooling" solution is laughable...
Only if it doesn't do the job.... don't judge a book by it's cover. Having the fan deep inside the case probably reduces the noise a lot so the location of the fan may not be so bad after all.

Sticking the Wifi antenna to the mains input is probably the easiest way to get it far from the metal parts without attaching it to the back shell.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: kayvee on July 02, 2017, 04:33:47 pm
ENIG plating, the rest has solder paste on top of it  :palm:

I'm fascinated. What is the purpose of this exposed gold?
Why gold? Why exposed?
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: Kleinstein on July 02, 2017, 05:17:10 pm
The chain of vias with exposed gold could be a place where the though they might need to add extra shielding. For a first version and a not so price sensitive board this might be acceptable.

The overall power consumption is not that high. So the cooling might be good enough. I agree that air flow is a little strange.

The DMM part at the back it rather strange - at least a simple 20 mm fuse for the lower current range(s) would be a big plus. This is especially important, as current readings might be an important function - you can read voltages with the scope already. Having an unprotected 10 A or so range is not that bad - not a good instrument for high power circuits anyway. However selecting the 10/20 A range with a different input can be tricky when you can not see the connectors.  This way I would prefer a cheap $10 DMM as a second unit - easy to replace if the shunt is blown and usually a more intuitive UI. It is only possible data logging you don't get with the cheap ones - but who knows if the SW supports this here. An added DMM function would be nice if fast (e.g. audio speed) - like usable as a slow 3rd channel.

Does one really need or even want Wifi on a low noise scope. I would be afraid it could be more trouble with interference than good.

Similar the VGA (or similar) output. Generally it is good to have one at a scope. However why  add a extra chip for a portable instrument with battery option. Good SW support for LAN would be likely as good.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: Fungus on July 02, 2017, 05:42:40 pm
I don't think that lack of fuses in the multimeter is a problem.

There's plenty of input 'protection' in the form of making it really inconvenient to move the leads to current measurement position. So much so that I expect people will just use a real multimeter for that. Owon saved us a few cents there.  :popcorn:

The VGA output is puzzling. Is there really anybody who'd want that?  :-//

Maybe the VGA output is for a really specialist use like Chinese electronic assembly lines and OWON are hoping to cash in on that.

(In fact  the combination of features on this device is just so weird that I suspect the entire 'scope is an attempt to cash in on one particular, specialist market).

Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: Someone on July 02, 2017, 10:27:29 pm
I don't think that lack of fuses in the multimeter is a problem.
Put any unfused mA meter in a student lab and get the stopwatch ready to time how quickly it will be destroyed.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: blacksheeplogic on July 03, 2017, 08:00:57 am
Put any unfused mA meter in a student lab and get the stopwatch ready to time how quickly it will be destroyed.

Students did not use to be this dumb, my first day at secondary school a teacher canned every one of us boys in his first class. Latter that afternoon a class mate put his feet up on a tool rack in a shop class. Old guy grabbed his cane and gave us another lesson in the use of good judgment. I'm 100% confident that had we been fortunate enough to have the use of a meter in class that it would have survived the year no problem.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: mikeselectricstuff on July 03, 2017, 08:17:51 am
I don't think that lack of fuses in the multimeter is a problem.

There's plenty of input 'protection' in the form of making it really inconvenient to move the leads to current measurement position. So much so that I expect people will just use a real multimeter for that. Owon saved us a few cents there.  :popcorn:

The VGA output is puzzling. Is there really anybody who'd want that?  :-//

Maybe the VGA output is for a really specialist use like Chinese electronic assembly lines and OWON are hoping to cash in on that.

(In fact  the combination of features on this device is just so weird that I suspect the entire 'scope is an attempt to cash in on one particular, specialist market).
VGA output is entirely reasonable - it's the composite that's really strange (assuming that's what that yellow phono/RCA socket is).
Owon have "previous" for terrible DMM designs. I really can't see how anyone thought it made any sense to include one in a scope like this, less so with the inputs on the back.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: Brumby on July 03, 2017, 08:48:49 am
I really can't see how anyone thought it made any sense to include one in a scope like this, less so with the inputs on the back.

My hypothetical:
 - New student graduate suggested adding a multimeter
 - Marketing says it's a great idea
 - Executives say "Do it"
 - Management says put it on the back, because re-tooling for the front panel is outside the budget
 - Engineer shakes their head and does what they're told.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: bktemp on July 03, 2017, 09:23:22 am
VGA output is entirely reasonable - it's the composite that's really strange (assuming that's what that yellow phono/RCA socket is).
Maybe because the DAC chip can do both?
The CH7026 seems to be a rather advanced video encoder: It has build in 16MBit SDRAM for framerate conversion, a video scaler and other stuff.

But that does not answer why they have used this chip. It doesn't look cheap and they could have used a much cheaper video DAC connected in parallel to the TFT data bus outputting the same 800x600 image.
It looks like they wanted a good quality composite video output for any reason.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: Fungus on July 03, 2017, 10:31:28 am
I don't think that lack of fuses in the multimeter is a problem.
Put any unfused mA meter in a student lab and get the stopwatch ready to time how quickly it will be destroyed.

I once did a "bring your meter" day at Arduino club and there wasn't a single intact fuse. Not one.

It doesn't help that they usually show a number on screen when the fuse is blown. Most of them assumed the meter was broken or something.

Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: Muttley Snickers on July 03, 2017, 11:04:57 am
It doesn't help that they usually show a number on screen when the fuse is blown. Most of them assumed the meter was broken or something.

You could almost incorporate that right there in some meters as a safety feature for the novice users, should a multimeter be turned on and a fuse blown then an internal counter would be incremented, when the count reaches three the meters display should scroll something like The user of this meter is a dickhead.   :-DMM :-BROKE :palm:
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: lowimpedance on July 03, 2017, 11:36:04 am
 :-DD, I can only imagine what the message would be for a 4th blown fuse!.   :wtf:  :-DD
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: GreggD on July 03, 2017, 01:15:49 pm
Just looked up the NEC UD2-4 relay at Digikey. Twelve types. No stock. Photo shows NEC but the manufacturer is listed as Kemet.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: EEVblog on July 03, 2017, 01:24:23 pm
VGA output is entirely reasonable - it's the composite that's really strange (assuming that's what that yellow phono/RCA socket is).
Owon have "previous" for terrible DMM designs. I really can't see how anyone thought it made any sense to include one in a scope like this, less so with the inputs on the back.

It's the latest craze of "5 in 1" etc feature scopes. They thought one-up other in marketing by adding an actual multimeter input instead of just a software multimeter.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: JoeN on July 05, 2017, 05:20:38 am
Just looked up the NEC UD2-4 relay at Digikey. Twelve types. No stock. Photo shows NEC but the manufacturer is listed as Kemet.

Kemet bought them out recently.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: maxwell3e10 on July 05, 2017, 10:48:40 am
It looks like HMCAD1520 can sample 4 channels in precision mode at 100 MSPS. Since they use one chip per channel (to get 1 GSPS in 8 bit mode), I wonder if they sample the same channel 4 times in 14-bit mode, maybe squeeze a bit more SNR.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: Smokey on July 05, 2017, 08:39:40 pm
Dave should add a stopwatch in the background of the fast speed reassembly.  I'm always interested in the amount of time it takes to put stuff back together.  That's typically the point where I regret taking something apart.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: Brumby on July 06, 2017, 08:03:34 am
Dave should add a stopwatch in the background of the fast speed reassembly.  I'm always interested in the amount of time it takes to put stuff back together.  That's typically the point where I regret taking something apart.

.... when you use a sundial?

I can understand the feeling.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: analognoise on July 06, 2017, 06:01:55 pm
What is up with the isolation slots on the DMM portion? Dave mentioned them, but could someone (Dave?) elaborate?
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: thm_w on July 06, 2017, 07:04:18 pm
What is up with the isolation slots on the DMM portion? Dave mentioned them, but could someone (Dave?) elaborate?

https://electronics.stackexchange.com/questions/74244/why-route-air-gaps-for-voltage-isolation-on-pcbs
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: WackyGerman on July 07, 2017, 01:58:45 pm
I am not impressed of that scope . The build quality is awful , the software and the multimeter are bad jokes . Would really prefer the RTB 2000 series from Rohde & Schwarz even with the glossy screen which I a not a real fan of . VGA output is also old fashioned , the HMO Compact Series offered DVI output and the design of these are some years old . There are absolutely no points to buy this scope , even for half the price  :--
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: tronde on July 07, 2017, 03:24:31 pm

The VGA output is puzzling. Is there really anybody who'd want that?  :-//


Makes really good sense in school setting together with a projector.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: maxwell3e10 on July 07, 2017, 05:05:29 pm
There are absolutely no points to buy this scope , even for half the price  :--

If you don't care about vertical resolution, there is no point. If you do, I would challenge you to find one even at twice the price with even 12 bit.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: Smokey on July 07, 2017, 06:34:37 pm
So that brings up an interesting question.  Say you want 12bit (or higher) high speed sampling, but don't need a full blown oscilloscope.  What is the best lower cost option in this price range for a data acquisition system with similar specs but not the front end or extra fluff like multi-meter and ARB?
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: maxwell3e10 on July 07, 2017, 08:24:17 pm
Picoscope 5000 is a USB scope with somewhat similar specs. Beyond that, there are various data acquisition cards from National Instruments, Gage applied and others.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: Smokey on July 07, 2017, 10:38:35 pm
... there are various data acquisition cards from National Instruments, Gage applied and others.

.... This was more what I was thinking.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: maxwell3e10 on July 08, 2017, 07:17:46 am
... there are various data acquisition cards from National Instruments, Gage applied and others.

.... This was more what I was thinking.
Those are generally more expensive, $5k and above, for high bandwidth devices. On the other hand, the USB scopes (Picotech, TiePie) are comparable in price ($1-2k). They actually use the same ADC chip as the OWON scope. Dave did a teardown of the Picotech 5000 a while back, it showed one ADC for 4 channels, while XDS3202A apparently has dedicated ADCs for each channel. Plus you get all the knobs, display and (optional) battery- a better deal than a USB scope.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: nctnico on July 08, 2017, 03:11:32 pm
The VGA output is puzzling. Is there really anybody who'd want that?  :-//
Makes really good sense in school setting together with a projector.
And how about connecting a framegrabber so you can record signals changing over time?
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: JPortici on July 08, 2017, 03:13:36 pm
... there are various data acquisition cards from National Instruments, Gage applied and others.

.... This was more what I was thinking.
Those are generally more expensive, $5k and above, for high bandwidth devices. On the other hand, the USB scopes (Picotech, TiePie) are comparable in price ($1-2k). They actually use the same ADC chip as the OWON scope. Dave did a teardown of the Picotech 5000 a while back, it showed one ADC for 4 channels, while XDS3202A apparently has dedicated ADCs for each channel. Plus you get all the knobs, display and (optional) battery- a better deal than a USB scope.

but you don't get to use the exceptional picoscope software suite and you are stuck with wathever spaghetti they cooked inside the owon
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: maxwell3e10 on July 08, 2017, 06:11:44 pm
but you don't get to use the exceptional picoscope software suite and you are stuck with wathever spaghetti they cooked inside the owon

I haven't used the Picoscope very much, so can't comment on the "exceptional" software. It does have API functions that can be used for real-time data analysis on a PC, so its more like a data acquisition system. For diagnostic applications of a scope for me having real physical knobs even with somewhat deficient user interface is better than software controls.
Title: Re: EEVblog #1004 - Owon XDS3202A 14bit Oscilloscope Teardown
Post by: JPortici on July 08, 2017, 10:42:13 pm
Recent updates modified the user interface to be more 'touch screen friendly' and i have to say it's much better to use with a mouse too.

At work i have a very long desk, which is divided as such: colleague - final test area - soldering area - me, so the board is always near my computer. It's very convenient to have the data already on the computer when i need it. Also big screen, etc.