You said it right on those Lawrence. I know a few resalers with stacks of them & although they are a good machine, if it frys....You are most likely screwed, because the same problems usually occurs with machines like that & finding good used (or even new) parts, almost an impossibility. The boards can be repaired, but it's a Pandora's box with those early inverters.
Running one off the fluctuating power of a generator, as you mentioned, would be a bad idea. Any rise or fall in line voltage could fry it instantly. Those old inverters, like the AP 350 & the XMT 300's are soooo touchy. The 300's are a much better bet, but all the same..... Old is old.
The Maxtron 450 did have a very good track record for an earlier inverter & many are still in service today. I sell the crap out of them when I get a deal on a lot of them. Just not a good machine to go balls out @ 38 volts all day, day after day though. :-) S.W.