VOLTCRAFT DOV series

[Martin72]

Access via the web console is fully restored.
The scope is now listed as ADS824A across all channels; FRA is no longer listed, which makes sense.
The main benefit now lies with the counter, as it now operates above 200 MHz.

[Aldo22]

Access via the web console is fully restored.

What did you have to do to get it working again?

@Olex: Have you made any changes to the script since yesterday?
Thanks!

[Martin72]

What did you have to do to get it working again?

Either it was because I had copied Olex's latest BootTxt.bin file over earlier.
Or because I reset everything to default.
In any case, it's working again.

[Olex]

Access via the web console is fully restored.

What did you have to do to get it working again?

@Olex: Have you made any changes to the script since yesterday?
Thanks!

Yes, I updated the script in the post
It turns out "ext_model" does affect the web application's operation after all

[Martin72]

I've written down the final steps—that is, once you've already modified the boot file and copied it to the USB drive—so I don't have to keep scrolling through the last few pages here.
Feel free to add the steps that come before these.

[Aldo22]

Yes, I updated the script in the post
It turns out "ext_model" does affect the web application's operation after all

Thanks!
For the 2-channel version, that would probably be

Code: [Select]

put_field(plain, 0x3C, “ADS822A”)  # int_model
put_field(plain, 0x50, “ADS822A”)   # ext_model
put_field(plain, 0x64, “OWON”)
Can you give me some advice on backups?
Which parts/partitions should I back up?
https://www.eevblog.com/forum/testgear/voltcraft-dov-series/msg6285410/#msg6285410

[Olex]

Yes, I updated the script in the post
It turns out "ext_model" does affect the web application's operation after all

Thanks!
For the 2-channel version, that would probably be

Code: [Select]

put_field(plain, 0x3C, “ADS822A”)  # int_model
put_field(plain, 0x50, “ADS822A”)   # ext_model
put_field(plain, 0x64, “OWON”)
Can you give me some advice on backups?
Which parts/partitions should I back up?
https://www.eevblog.com/forum/testgear/voltcraft-dov-series/msg6285410/#msg6285410

Just the /oem folder -  all the oscilloscope's settings and parameters are in there.

But overall, you could dump the entire MMC just to be safe.

Code: [Select]

DS01:/ # dd if=/dev/block/mmcblk0 of=/storage/1BFA-0317/mmcblk0.img
"1BFA-0317" - will become the unique ID once you plug in a usb flash

[Aldo22]

Just the /oem folder -  all the oscilloscope's settings and parameters are in there.

But overall, you could dump the entire MMC just to be safe.

Code: [Select]

DS01:/ # dd if=/dev/block/mmcblk0 of=/storage/1BFA-0317/mmcblk0.img
"1BFA-0317" - will become the unique ID once you plug in a usb flash

Thanks, I've already copied the oem folder.

Not really knowing what I was doing, I also ran these commands:
dd if=/dev/block/mmcblk0p1 of=/storage/BB72-06B8/boot_backup.img
dd if=/dev/block/mmcblk0p3 of=/storage/BB72-06B8/system_backup.img
dd if=/dev/block/mmcblk0p10 of=/storage/BB72-06B8/oem_backup.img

Will this help me if something goes seriously wrong, or is it insufficient or complete nonsense?
I have no experience with this on Android.

EDIT: OK, I see your "Edit".
I should copy the entire "disk".

Thank you.

[Aldo22]

The “upgrade” also works with the two-channel version.
But yes, the bandwidth remains the same.

I wanted to make a “backup” first.
Here's how to do it with a FAT32 flash drive (4GB file size limit):

Code: [Select]

dd if=/dev/block/mmcblk0 | gzip > /storage/5496-CF0C/dov_backup_img.gz
Thank you Olex! 

[Aldo22]

Did I just never notice this “record” thing before, or is it new?
Is there a description of it somewhere?

[Martin72]

https://files.owon.com.cn/probook/ADS800A_Series_User_Manual.pdf

Starting on page 107, that feature isn't available on the Voltcraft.
Owon seems to have left out quite a few things from the DOV...

[Aldo22]

https://files.owon.com.cn/probook/ADS800A_Series_User_Manual.pdf

Starting on page 107, that feature isn't available on the Voltcraft.
Owon seems to have left out quite a few things from the DOV...

Thanks! 
What else does the Owon have that the Voltcraft doesn't?

[Martin72]

According to the Owon manual, there should actually be an axis label in the display menu.
But I haven't found it—either it's a “bug” or the “conversion” to the ADS800A isn't quite complete yet.
However, the waveform player seems to contradict that—why would that be available now, but not the other feature...

[Aldo22]

According to the Owon manual, there should actually be an axis label in the display menu.
But I haven't found it—either it's a “bug” or the “conversion” to the ADS800A isn't quite complete yet.
However, the waveform player seems to contradict that—why would that be available now, but not the other feature...

Yeah, are there actually small improvements just because you tell it it's an Owon??
That's strange.

For example, you can now set the Peak Display Threshold to -100dB. Before, it was only -50dB, which wasn't enough.

[Martin72]

Yeah, are there actually small improvements just because you tell it it's an Owon??
That's strange.

It is..

Oh, right, I ordered that fan; it should be here soon...

[Aldo22]

Oh, right, I ordered that fan; it should be here soon...

Great! I'm looking forward to your review.
I could buy it here, too.

[Aldo22]

By the way: Watching EEVblog videos on the DOV is no problem at all. The sound comes through the Bluetooth speaker.

 

[Microcheap]

Sorry for the delay, lots of new messages and I see there is some interesting development regarding hacking this scopes. I'll try to catch up.

Mean while, I finally manage to take a few more pictures of the ADS914A board. I am posting the ones I think are a little better. I also had to reduce the images sizes. To get all pictures with the original resolution check here.

[Microcheap]

A few more pictures.

I also checked the FFT in the ADS804A and ADS914A, both works as expected (signal is from the from the probe compensation terminal).

[Aldo22]

It seems you've actually ended up with a defective unit; I'm not sure what the problem might be.
Put it back in the bag and send it back.

I've thought this through carefully.
One problem is: I've exceeded the standard return period (without needing to provide a reason).
I wasted part of that time waiting for a response from Conrad's "Qualitätssicherung" regarding the ripple issue.

Now I'd have to file a warranty claim.
I'm afraid the problem is too unclear for that.
Conrad wouldn't even admit to the obvious ripple issue.

The "classic" oscilloscope part works, as far as I can tell.
There are only issues with FFT and XY mode at a memory depth of more than 1k.
Sometimes XY doesn’t flicker at 10k either; I don’t know why.

How am I supposed to describe this to Conrad?
They can always play dumb and say, “It works just fine.”

The bugs aren’t that serious to me. XY “animation” with more than 1k gets slow anyway.
FFT, well. It would be nice if it worked, but...

On the other hand, there’s the hassle of packing it up, shipping it (which also costs 12.-), and I have no idea how Conrad handles this.
In the end, I’ll probably end up paying for the inspection and the fruitless return.

Do you have any experience with Conrad in this regard?

[Olex]

Sometimes XY doesn’t flicker at 10k either; I don’t know why.

Try enabling it in the Android settings:
Developer options -> Force GPU rendering

This will improve overall animation smoothness, and there's a chance the flickering in XY will disappear.

[Aldo22]

Sometimes XY doesn’t flicker at 10k either; I don’t know why.

Try enabling it in the Android settings:
Developer options -> Force GPU rendering

This will improve overall animation smoothness, and there's a chance the flickering in XY will disappear.

That's definitely a good tip!
It makes the animation run faster.
But the flickering in XY mode (actually artifacts, see screenshot #1) gets even worse unless I switch to “Average” (2 is enough); then it looks good even at a memory depth of 100k (screenshot #2).

That’s exactly the problem: How am I supposed to describe a warranty claim if I can’t quite grasp the circumstances of the problem myself?

[Martin72]

Hi,

How am I supposed to describe a warranty claim if I can’t quite grasp the circumstances of the problem myself?

Send the picture with...
That should be enough—and it will be.
I don't think Conrad will make a big deal out of it.

[Aldo22]

Hi

Send the picture with...
That should be enough—and it will be.
I don't think Conrad will make a big deal out of it.

Why do you think that?
According to “Qualitätssicherung”, the 200 mV ripple is just an operator error. I included a picture of that as well.
Why would it be any different with this even more elusive problem?

[Martin72]

Which just proved that quality assurance hadn't even looked into the problem.
I would resend the images showing the 200 mV issue, along with the images from XY mode and the FFT.
Then they should be able to reproduce it, and if they still think it's a user error, well, then they should show how to operate it correctly.
I'd be very surprised if that were possible.