We have a Magnun Inverter in our Motorhome. I just put in all new batteries. The meter inside the RV where we check the inverter and turn it on now will not work. There i a constant green light, but the actual Inverter screen just has rows of dashes and does not work. I manually turned off the invester under the RV -- but am totally confused why that inside switch and screen no longer works. It is how I turn it on and off while camping. Can anyone give us an an idea how to fix it or what can be wrong?