We used our Cascade last in July. Just went to check on it. It's parked under my barn and hooked up to power. Everything is dead. No lights, power control panel, no power except micro wave when plugg...
Check the fuses to your converter. Its in the under area storage.
I had a similar problem. On mine, one was loose ( appeared it was built that way, I had to bend the tabs to get a good fit ) and one was blown and it prevented the batteries from charging.
Make sure you shut off the master power at entry to the door and unplug the unit before you do any of this.
If you need to open your slide you can use a battery charger on the two 6 volts. ( I also had to do this)