Thanks for yor suggestions. But nothing of those advises are usefull in my case, since there is no ligth in any oprearating button. I have already disassembled all the base included the electronic board. But there is not easy to find a replaceable fuse.
So I shall wait till next monday to check if the charger adapter is working and giving the 24v DC. It may be the reason of not having energy in the device. If I find something new I shall post it for general knowlege.