Export from 7.4 and import to 8.0 - unicode errors

I'm getting Unicode errors when I export (with pg_dump) my database from
version 7.4 and then import it into a new 8.0 database (with psql).

The situation is that this data has fields with ascii characters in them and
utf-8 characters also.  Both types of characters are in a given field.  The
entire dump is NOT utf-8 encoded.

I can't figure out how to get this to be imported into the new database
without errors unless I turn the entire thing into utf-8 using recode. That
does not work well because the fields in question have to be utf8_decoded (in
php) TWICE before they display correctly.

How do I deal with this?  It's got me very puzzled!

Thanks!
Scott