Had a power surge from grid a while back and this then required a new control board to be fitted. This has been done and the inverter side works fine now but when connected to AC power in, this does not register and charge the batteries or switch the inverter side off. There is none of the LED operating on the left side of the unit either? Having looked at documentation it is telling me that it may be a fuse/breaker on the AC in side that needs to be closed, any ideas where?