I'm running:
- MultiPlus II 48/3000 with latest firmware
- No AC input
- Switch position "1", Switch position "2" wont' turn on the device
- Unit is not connected to physical earth.
The unit hums at 50Hz to the point where it's disturbing my sleep. Everything is functioning normally. The hum is independent of load, though when the cooling fan comes on, it drowns out the hum. The unit will hum for about 2hrs then will go silent for 1/2hr, and repeat that cycle ad infinitum.
In my other installation, the MP 2 does not hum like this.
Is it a fault? Can it be solved?
