[DM-MUG] iMac G5 won't mount LaCie 500G external HD

[Victoria L. Herring]

Firewire HD, used to work fine but noticed today it wasn't on desktop 
so checked everything out and switched cables and repaired permiss. 
and restarted and the plugged it back into the iMac and the only 
thing I can hear now is a very faint clip-clip-clip - sort of like 
faint druming of fingers or horses clip clopping along -- using FW 
400 cable ==  but then I plugged it into my G5 and it sounds like 
it's coming up as usual and it mounted right up.  Using FW 800 cable

why would this happen and what can/should I do???  The iMacG5 seems 
to be fine otherwise and it doesn't get hard use really...it is, of 
course, covered by AppleCare if need be.  But only this drive seems 
to be having a problem.
-- 
Victoria L. Herring, Attorney, Civil Rights, Discrimination & 
Employment Law, <http://www.HerringLaw.com>;  Travel research, 
planning & Photography, <http://www.JourneyZing.com>;  Des Moines, 
Iowa, ph.515-255-4475.