Hi and welcome to JustAnswer,Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially, let's try review the basics (if have not been done):
Have you considered / tried a RESET?
A reset is both a test and a try of a fix. As it implies, a reset would force the unit to revert back to factory defaults removing glitches and config errors but would include memories, presets and user preferences. After a reset, the initial setup would have to be performed. If have not been done and should you venture to try:
This is very critical - a reset however would not be corrective of an internal hardware concern; but it would be confirmed. In some instances, it may even expose/cause other issues.
Please click HERE.
The DISPLAY OFF button would be between the SLEEP and MUTE buttons.
The above posted RESET procedure is from p. 31 of the Marantz SR7000 User Guide.
Still, if a RESET can not be performed on the SR7000, then it would confirm the internal hardware issue as posted above.
Are you then considering a DIY (do-it-yourself) repair approach? If yes, do you have access to and familiar with a multi-meter and even a soldering iron?
I understand and it would appear that you have a European version.
The only easy user doable try then would be the RESET.
Another is unplugging for a really extended period of time; preferably overnight.
All others would be internal.
Cycling the power (switching On-Off-On-Off-On) is also a form of reset but is 'by chance'; a hit-or-miss method hence unpredictable reliability.
Of course it may happen again.
...but then it also may not.
I realize that the above information may perhaps be not what was expected. Unfortunately, there is no quick-n-easy fix and neither is there a workaround; sorry for having to be the bearer of bad news.
Appreciate your kind understanding.
Good luck and thank you too for the opportunity to be able to share the information.
Glad that the above tips / information may serve your purpose and would appreciate a Positive Rating and/or an Accept (if haven't done so) as this is the only way I get credit.