Re: no manual
The unit in back is 115v but the one towards the front is DC only and has a standby light that is always on regardess of hookup. It stayed on for a couplle of hours and then the screen went blank but the sound continued. It might be connected to vehicle battery? If so then the engine must be on for the main battery to charge so the voltage is up enough for this unit to work. Everything else seems to run when unit is plugged in.