Hacking the Rigol DHO800/900 Scope

[bluesky-ca]

No luck finding PWM - I looked at the boot messages and nothing stands out.  The fan53555 is a PWM voltage regulator with lower output voltage.

Here are few other things that might be of use:
1) Setting HDMI resolution - on DHO800 line there is no direct menu item to set the resolution - for some reason my monitor got 1920x1200 and the output did not look right - here is a quick fix: 
with a kbd connected: WinKey-N → Settings Gear Icon → Display → HDMI → Resolution → 1920×1080

Its possible to set the resolution using adb as well but the string has some magic numbers - after you set it using the above method you get find out what the value is:
adb shell 'getprop persist.sys.resolution.aux'
- use setprop to set the value

2) NFS mount - if one needs to move a lot of files or wants to save items directly on their NAS from the scope ( ie wave images, recordings, settings).   One plus is that it does not impact the SD card and can increase its life ( doing the mount does not remove any of the existing files in /data/UserData ).  I assume you have an nfs server on IP 1.2.3.4 running over TCP with version 4.2 and has an export disk /rigol:
adb shell
su -
busybox mount -t nfs -o proto=tcp,vers=4.2 1.2.3.4:/rigol  /data/UserData
chmod a+rw /data/UserData

- the write speed is about 10MB/s based on my tests.  Right now the mount does not persist over reboots - I may add some scripting to run at boot time, or you can have a script running from a remote host and perform the mount using adb shell su -c ... command.

3) Use busybox to find missing commands - I like less, so in the shell I can say alias less='busybox less' and now have a less command - to see all commands type busybox

[Fungus]

Here are few other things that might be of use:
1) Setting HDMI resolution - on DHO800 line there is no direct menu item to set the resolution - for some reason my monitor got 1920x1200 and the output did not look right - here is a quick fix: 

Much easier: Tap the "about" button three times and you get settings for the HDMI resolution.

[vanyas]

Taking a good quality screenshot (better than via web ui)

Code: [Select]

adb exec-out screencap -p > screen.png

[Randy222]

The fan53555 is a PWM voltage regulator with lower output voltage.

I wonder what that is used for.

Onsemi has that model #, it could change voltage depending on thermal load. Programmable via I2C, so perhaps that's easier to program than using PWM. Perhaps the constant "flicker" of PWM is a no-no for a scope device like this?

"The FAN53555 is a step-down switching voltage regulator that delivers a digitally programmable output from an input voltage supply of 2.5 V to 5.5 V. The output voltage is programmed through an I2C interface capable of operating up to 3.4 MHz."
 

[bluesky-ca]

I now recall reading about tapping on About but for some reason I assumed it was one of the Android menus - this way is much easier - thanks.
I do wonder why they have to hide the item or maybe I missed it in the manual   

[sonic]

With today's OTA to 00.01.02, the Storage depth option seems to have disappeared, too:

[vanyas]

With today's OTA to 00.01.02, the Storage depth option seems to have disappeared, too:

It's disappeared from options list, but still working. And for me, dho924 vendor.bin has no offset on 00.01.02

[t_i_t_o]

Anyone saved and willing to share 1.02 as it seems to be gone from any of rigol sites?

[Randy222]

Anyone saved and willing to share 1.02 as it seems to be gone from any of rigol sites?

I thought fungus said it was being pulled back?
I never did download a 01.02 version.

[dmulligan]

The fan noise doesn't bother me. 
For those who it does bother; have you tried changing the pwm frequency or duty cycle using the original fan and an external source?  This would identify if the harsh, to your ears, sound caused by the fan or the pwm which drives it.

[enson72]

It has been determined for a long time. The noise is caused by the design of the execution. Air raid sirens are designed according to this principle.

[dmulligan]

It has been determined for a long time. The noise is caused by the design of the execution. Air raid sirens are designed according to this principle.

Some fans whine at certain pwm frequencies.  Are you saying that you know for a fact that this is not a contributing factor in DHO800 oscilloscopes?

This is a well known problem in the diy 3d printer community.  A quick search shows this has been discussed here too.  At least one thread here has a better test suggestion.  Instead of using pwm, use a variable power supply to see if it reduces the fan noise.
Eg. https://www.eevblog.com/forum/beginners/filtering-pwm-to-smooth-dc/ 

[Randy222]

I did some sleuthing arund on the various Rigol sites using nifty F12 via Firefox. Their sites are heavy in .js imports, so needless to say I had to read through many .js files looking for clues.

The two 01.01 downloads, one with Aug 2023 date, the other Dec 2023, are all the same zip file. I suspect the 01.02 zip was attached to the Dec 2023 download, until they swapped it back to 01.01

I was not able to locate a 01.02 download.

I will contact Rigol support since my unit has 01.02 and ask for the 01.02 zip.

[enson72]

It has been determined for a long time. The noise is caused by the design of the execution. Air raid sirens are designed according to this principle.

Some fans whine at certain pwm frequencies.  Are you saying that you know for a fact that this is not a contributing factor in DHO800 oscilloscopes?

This is a well known problem in the diy 3d printer community.  A quick search shows this has been discussed here too.  At least one thread here has a better test suggestion.  Instead of using pwm, use a variable power supply to see if it reduces the fan noise.
Eg. https://www.eevblog.com/forum/beginners/filtering-pwm-to-smooth-dc/

Why complicate it? It's much simpler. You take the fan out of its socket and realize that it is not making noise)) You can easily find information on how an air alert is set up on Google. I screwed an external cooler to Rigol, and no PWM prevents it from working quietly. Take a look and everything will become clear. In the photo there is an air raid siren

[iMo]

So, what should be the right shape for the fan with the existing heatsink?
Talented designers here may print out the rotor/blades and try..

[Demon Xanth]

I've been a lurker for a while but figure I have something to add here.

I have a DHO804 that I had done the SCPI mods to successfully, and currently have a 914 vendor.bin that self cal'ed properly. I've been running FW 1.02. I got mine via Valuetronics. I still have the 1.02 firmware on my HD, so here you go.

https://file.io/s9E8WaojBr0N

[voltsandjolts]

Is that file auto deleted after one download (i.e. free use option on file.io) ?

[Randy222]

Is that file auto deleted after one download (i.e. free use option on file.io) ?

I get a "file deleted" message.

[Randy222]

What does the 804 become when you change just the model number to 914 in the vendor.bin file? And when doing that, any diffs between 1.01 and the 1.02 FW?

800/900 uses same firmware, and there are hardware diffs between 800 & 900, so what all do you gain with just a model number change in vendor.bin?

[Demon Xanth]

That was my first try at File.io, let me try dropbox...
https://www.dropbox.com/scl/fi/qdo6kfje8coxgxbgp9012/DHO800_DHO900-Software-Updatev00.01.02.00.00.zip?rlkey=35rzumxdyw7g6qfsv8j9flztr&dl=0

I went for the 914 to gain the CAN decoders since I frequently work with CAN bus stuff. Otherwise the BW upgrade would have been fine. I'm hesitant to buy a probe and cut a hole in my case since my cutting skills aren't pretty and I have a Saelea pro 16 on hand.

[Randy222]

That was my first try at File.io, let me try dropbox...
https://www.dropbox.com/scl/fi/qdo6kfje8coxgxbgp9012/DHO800_DHO900-Software-Updatev00.01.02.00.00.zip?rlkey=35rzumxdyw7g6qfsv8j9flztr&dl=0

I went for the 914 to gain the CAN decoders since I frequently work with CAN bus stuff. Otherwise the BW upgrade would have been fine. I'm hesitant to buy a probe and cut a hole in my case since my cutting skills aren't pretty and I have a Saelea pro 16 on hand.

Got it.

What's not in the Release notes? Reply#661 is not in the release notes. Why is that option removed?

Variants of 00.01.01.00.xy All of the 01.01's downloadable from Rigol are the same zip file, so I wonder who is running a 01.01 variant?

What the heck is item #4?
Release notes:

Code: [Select]

[Model Supported] All the DHO800/900 series oscilloscopes
[Latest Revision Date] 2023/11/2

[Updated Contents]

v00.01.02.00.00  2023/11/2

1. Self calibration optimization update
2. Solve the problem of UltraLab startup connection failure
3. Solve the problem of failure to save waveform in wfm format
4. Add education model equivalent settings
5. Solve the problem of unresponsive touch on startup screen

v00.01.01.00.02 2023/09/12

1. Self calibration optimization update
2. Update Help Documents

v00.01.01.00.01  2023/08/10

1. Remove all time-related displays on the instrument
2. To modify the vertical interface, click the wiring diagram to modify the AC coupling function
3. Modify the delayed scan Chinese display as Zoom
4. Modify the order of the menu in the upper right corner, put the measurement in the front and Default in the back
5. The probe ratio interface is removed, and the probe ratio option is added to the vertical first-level menu


v00.01.00.00.19  2023/07/24

1. The first version is released


-Released the production version.

[Fungus]

What does the 804 become when you change just the model number to 914 in the vendor.bin file?

A DHO914, believe it or not... 

[Randy222]

What does the 804 become when you change just the model number to 914 in the vendor.bin file?

A DHO914, believe it or not... 

Not quite, right. 900 has more hardware in it. I wonder what the android error logs look like if the OS ("fw") is expecting all the 900 hardware?

So with just vendor.bin mod to change model to "914", the 804 becomes a 4ch    12 Bit   125 MHz   1.25 GSa/s   50 Mpts   1,000,000 wfms/s, with no calibration or other issues ?

[Fungus]

So with just vendor.bin mod to change model to "914", the 804 becomes a 4ch    12 Bit   125 MHz   1.25 GSa/s   50 Mpts   1,000,000 wfms/s, with no calibration or other issues ?

Yes.

(actually 225Mhz measured bandwidth...  )

You also get the 2ns/div horizontal and 200uV/div vertical ranges, and the CAN/LIN serial decoders.

[dmulligan]

It has been determined for a long time. The noise is caused by the design of the execution. Air raid sirens are designed according to this principle.

Some fans whine at certain pwm frequencies.  Are you saying that you know for a fact that this is not a contributing factor in DHO800 oscilloscopes?

This is a well known problem in the diy 3d printer community.  A quick search shows this has been discussed here too.  At least one thread here has a better test suggestion.  Instead of using pwm, use a variable power supply to see if it reduces the fan noise.
Eg. https://www.eevblog.com/forum/beginners/filtering-pwm-to-smooth-dc/

Why complicate it? It's much simpler. You take the fan out of its socket and realize that it is not making noise)) You can easily find information on how an air alert is set up on Google. I screwed an external cooler to Rigol, and no PWM prevents it from working quietly. Take a look and everything will become clear. In the photo there is an air raid siren

I never suggested removing the fan, just connecting it to a different power source.  Taking the fan out of the case may change how it resonates. 

Anyhow as the sound doesn't bother me at all, I won't be opening mine.  I was trying to offer something to try which may offer a less physical hacking way to reduce the sound for those who it does annoy.  For all I know the fan runs on DC rather than PWM.