Better get into the fine print then of who is responsible for the shipping and who is liable for shipping damages. It is time for you to seek legal advice about what your rights are here.
I have checked with my colleague who had in charge the calibration: oscilloscope and other non electronic instruments have been sent to a company (A) for calibration. This company (A) sent the oscilloscope to another company (B) for calibration and a certificate was issued. Then the oscilloscope was sent back to company (A) and then back to me.
I have found the issue after about 1.5 months after the calibration as I don't use it everyday and now, from what I saw with your help, I can probably say that it was because I only used one channel.
So what they are saying is that it was damaged during the delivery or that I have used anda damaged (without any proof) and so they are not responsible for that. I will check with the purchasing office, but probably a lawyer and all the bureaucracy around is more expensive than an ex-demo.
According to the user manual:
Service manual
Describes the performance test for checking the rated specifications, module replace-
ment and repair, firmware update, troubleshooting and fault elimination, and contains
mechanical drawings and spare part lists. The service manual is available for regis-
tered users on the global Rohde & Schwarz information system (GLORIS, https://
gloris.rohde-schwarz.com).
Do you know if the service manuals are available for end users too or only for some labs/services?
Is this random "noise" looking same on both CH1 and CH2? If it does, than it cannot be analog front end. It must be with ADC or after..
Well, that particular defect might not have to do anything with the calibration. Maybe vibration in transport exacerbated the problem, but probably it is manufacturing defect. If scope has no visible signs of mechanical damage, electronics could not be damaged in this way by cal facility. There are many occasions that scopes fall of the desk, are visibly completely broken but power up just fine and work. There was a guy here on EEVBLOG that repaired a Keysight 3000A scope that had car run over it in a parking. He had problems finding pieces of the case, but scope worked fine.
Problem is most likely in ADC for those CH or in acquisition data pump/memory part for that ADC.
It is either IC defect (bonding defect for instance) or soldering..
If warranty is not there, careful disassembly and testing with cold/hot air or gentle tapping around the board might reveal
location. In which case if it is soldering, it might be fixed by reflow.
I wouldn't go lawyer path. They will be more expensive than scope in just few hours.
Just get the "new" demo one and get insurance for it this time.
I don't know if R&S has extended warranty maintenance contracts like Keysight.
With Keysight they are actually good deal. Maybe ask them.
Once you have replacement working scope, you might try repair old one. If you succeed, you have another one.
But you would need to send it to calibration again to verify it's working OK. Or just perform performance verification yourself if you have equipment.