My (new to me) 2003 Scamp came with a Parallax Power Controller, model 6730.  That unit recently failed so I bought another one off of Amazon and had a RV tech come to the house to install it.  The unit was defective, putting out 20 volts.  So Amazon sent me another unit, the tech came over again and installed it this one.  It worked for one day just fine and then it stopped charging my house battery.  It is also not converting the 110 Volts to 12V power.  It does work fine running the fluorescent light and providing power to the 110 outlets in the trailer.  Amazon has been good and provided a full refund.  After buying two of the Parallax units that were defective I am looking to put in something else.  Looking at a photo of the Progressive Dynamics model PD9130 I see it is very different than the Parallax Unit.  If I were to get one of these I'd also get the battery wizard too.  In photos I don't see any fuses like I have now on the Parallax Unit, why not?  Would a PD9130 be a good replacement for the Parrallax Unit?  Will it be hard for my tech to make the switch?  What's involved in switching over?