PMU issue/ external hard drives aren't recognized

I've got a similar problem to an earlier post by CMORTON. My G4 has been acting up...it'll state that the time is set incorrectly and then my external hard drives won't be recognized when I plug them in. A couple of days ago I tried resetting the PMU, and that worked for a few days, but the issue has cropped up again. Any idea what I might try next?
thanks!

Are you external HDs connected via USB or Firewire?
Look at these links.
USB and FireWire Quick Assist
http://support.apple.com/kb/HT1151?viewlocale=en_US
What to do if your computer won't recognize a FireWire device
http://docs.info.apple.com/article.html?artnum=88338
Dealing with FireWire problems (drives not mounting, devices unrecognized, etc.)
http://www.macfixit.com/article.php?story=20041221081432908
Common fixes for USB device issues (unrecognized, etc.)
http://www.macfixit.com/article.php?story=20070824012114701
 Cheers, Tom

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