Bill,
With no clue what the subject RV is, lets try to get around that.
You say that the line power stuff works on line power, the battery stuff works when you have no line power, but not when you do.
If that is correct, look at you converter/charger. It may be a unit that is so old that it had separate converter and charger sections and when it had line power, it would switch the house demand from the house battery so that did not interfere with charging the house bank.
It could be that the part that is supposed to supply the house power when not on battery is dead. It could be either the power supply circuit itself, or the contactor. If you power surge was enough to damage things, I would bet on the house power supply.
Matt