Thanks a lot for sharing the info.
Now I realized that the fuses on the left of the AC connections are for the PV circuits.
A new hardware revision, probably after the problems with the fires on the PV section.
But the board below is an additional one… Is it also for the PV circuit?
I have the feeling that’s a board with some surge protectors, like in the old MultiRS TR version (without MC4 connectors).
Like the ones here: MPPT RS 450/200 PV board red switches - #2 by alexpescaru
Can you confirm it?
Many thanks again and sorry for hijacking the topic with other things!
Back on the original issue, in my case, the fan sounds became somehow deeper (lower in frequency) and helped, because I sleep in a room pretty close to the inverter and, maybe I am weird, but I sleep better with that sound… 