1998 Dolphin class A 36 ft motorhome. 220 instead of 110

I read a lot of posts about people plugging into 30A outlets and getting 220.

First thing I'd do is pull out the multimeter and start testing. Hot to neutral may be one way of wiring, but there are tons of wiring hackjobs done in the past out there (hit your favorite search engine for "bootleg ground" for example), so it might be that what should be one voltage is something completely different.

If your RV did see 220, the converter almost definitely will have to go.