[R] Rd files with unknown encoding?

[Spencer Graves]

      How can I identify the problem generating a warning in R CMD check 
for "Rd files with unknown encoding"? 

      Google identified an email from John Fox with a reply from Brian 
Ripley about this last 12 Jun 2007.  This suggests that I may have 
accidentally entered some possibly non-printing character into the 
offending Rd file.  The message tells me which file, but I don't know 
which lines in the file.  Is there some way of finding the offending 
character(s) without laboriously running R CMD check after deleting 
different portions of the file until I isolate the problem? 

      Thanks,
      Spencer Graves