RTA4004 Warranty Issue or Firmware Bug?

[Odysseus]

I'm looking for anyone with an RTA4000 series R&S scope that could check if this problem I've encountered is isolated to my instrument. The summary is that channels 1 and 2 will sometimes appear on the display as if they were un-triggered, with random time alignment, even though channels 3 & 4 are stable and channel 1 (or 2) is the trigger source. The attached screenshot does a good job exemplifying the issue. Just a single 10MHz square connected to all four inputs.

It only happens when the FFT function is enabled with high resolution acquisition enabled. I've also exported and attached the setup file to make it easier to replicate.

[egonotto]

Hello,

i can not load you setupfile.

Best regards
egonotto

[2N3055]

Make sure you are running latest FW version in a first place.
Also if  it is a 10 k€ scope in warranty, first step is to contact point of purchase and R&S support.

[Odysseus]

Hello,

i can not load you setupfile.

Best regards
egonotto

Thank you for trying.
I am able to load it back onto my scope, but it does seem like I uploaded the wrong version.
I've attached another, which I've confirmed loads correctly after a Preset and recreates the issue.
Note that I've uploaded a .zip file, which needs to be extracted first.

Make sure you are running latest FW version in a first place.
Also if  it is a 10 k€ scope in warranty, first step is to contact point of purchase and R&S support.

Yes, the very first thing I checked, the firmware is the most recent for the RTA4000 series, 01.700.
I did eventually figure out how to submit a ticket to R&S, but it was more convoluted than I expected. I'm not confident I'll even get a response.
I would also be frustrated if I sent it in for warranty and I got it back with the same problem, because it's a firmware issue. Hence my post.

[egonotto]

Hello,

i can again not load you setupfile.
I have Firmware Version:    01.700 but not US
I only changed the voltage to 50 mV because I use a BNC connection.
If I activate FFT, I can no longer change the deflection time. It is now 34.95 us/div.
You can explain to me how I can make the setting by hand, or you can contact pdenisowski from R&S who recently wrote here: https://www.eevblog.com/forum/testgear/scope-recomendations-in-$15-20k-range/

Enclosed is my setup file.



Best regards
egonotto

[Odysseus]

Your setup file will load on my scope but throws a similar server error. Oh well.

The minimum steps to recreate is:

• Preset
• Set time scale to 80ns/div
• Set Acquisition to hi-res
• Turn on channel 3
• Apply identical signal to channels 1 and 3
• Enable FFT
• Wait 5 to 30 seconds

Thanks for taking the time to help, and thanks for the contact. I'll see if my ticket gets a response, and ping pdenisowski otherwise.

[pdenisowski]

Thanks for taking the time to help, and thanks for the contact. I'll see if my ticket gets a response, and ping pdenisowski otherwise.

Please do

[egonotto]

Hello,

I am also experiencing this problem. After a few seconds, the triggered channel runs and the untriggered channel remains stable.
It even gets worse later.

Best regards
egonotto

[nctnico]

As I expected, I can reproduce the effect on my RTM3004 as well. Let's classify this as a firmware bug. Cycling through trigger or FFT settings makes the signal stable for a while but then it goes off again.

[Odysseus]

R&S support has also been able to replicate the issue and filed a bug report, but advised me there is no guarantee this will receive a firmware update, as engineering is currently focused on the MXO series.
It appears that using only channels 1 & 2 or only channels 3 & 4 at a time will avoid triggering the bug.
Unfortunately, that puts the scope into 2.5GS/s instead of 5GS/s, so aliasing becomes an issue at higher frequencies.

Thanks again for your help.

[nctnico]

R&S support has also been able to replicate the issue and filed a bug report, but advised me there is no guarantee this will receive a firmware update,

That would be very dissapointing...