Sorry to highjack the thread
but:
A few days ago I acquired it and it has problems with overheating, the fans do not activate correctly until it is about to reach 70 ° causing restarts and cannot be modified
Do you know if the fans are working at all? Like all of the active cooling devices they should at least run for a bit on start up, do you want to double check that this behaviour is present?
I have not had a chance to open one of these yet but I would assume that they are like the other CCR's and have multiple fan headers, are you able to check that you have the right fans selected in the system>health menu or even open up the device and make sure the connectors have been plugged in the right way to the fans's headers?
If this hardware troubleshooting does not work I would generate a supout of the device during and right after the overheat event and sent it off to your supplier to see if they can bring this one up with Mikrotik or potentially RMA the device?