i think i might have founs an error on this page : http://www.everlastgenerators.com/Po...26-380-pd.html
at the bottom "ac balance control" and "ac freq" seem to be reversed. ie
ac balance control reads 20-250 hz and ac freq reads 10-90%. i could be very wrong, but i think those should read: ac balance - 10-90% and ac freq - 20-250hz.