Thank you for your quick reply.
Technical Support wrote:
Did you update the firmware yourself? If so, is the SD card still in the unit? If so, remove it and see if the problem persists.
-> There is no card SD left in the flash. The problem occourd before the firmwareupdate, too. I did the firmwareupdate because I thought it would fix the problem.
Technical Support wrote:
If that is not the case, are you using any remotes? Particularly if you are using an MC2 or CSXCV, Remove it and see if the problem persists.
-> I disconnected any remotes for the testing but the problem persists.
Technical Support wrote:
Does the same thing happen with both a wall socket and VII (i.e. wont turn on, then will after a few minutes)?
-> Yes!
I had a shooting and used the VII. After a break of 20 minutes (I turned off the Einstein and the VII) the flash did not power on again. I continued the shooting with an ABR800 connected to the VII.