G5 Won't Deep Sleep After Sw Update


My single processor 1.8 Ghz Power Mac G5 will not deep sleep after s/w update from Apple. It will deep sleep after an archive reinstall of the original Panther family pack (OS X 10.3), but it no longer deep sleeps after s/w update to 10.3.9.

Symptoms after going to sleep:

1) Fans stay on
2) Sleep light stays on
3) Mouse stays powered (laser light)
4) Other units still powered???
5) Monitor goes to power save
6) System won't respond to pings
7) System wakes normally (also with mouse movement, as it is still powered)

Have had at Apple store twice for this problem and they recommended full disk wipe and fresh OS install. This was performed, but got same symptoms just after s/w update.

I have 2 years remaining on Apple Care, but don't care to loose my machine for "research." I use it daily.

Any help would be appreciated.
I did the firmware update as you recommended and it works! Here's the reason's I did not do this in the first place:

1) Assumption that when the Apple Genius personnel performed the 5.1.5 firmware update (which I watched them do) for me 3 weeks ago that they did this very update - bad assumption.
2) My s/w update listed 5.1.5f2 firmware as available, but I never selected it because I assumed it had been installed per above, but wasn't. Apple installed an earlier version of the 5.1.5 firmware which did not fix this problem.
3) Failure to find adequate search results on this problem when searching Apple support site with several different queries. General search queries returned too many articles and more limited filters returned nothing.

Anyway, thank you very much. This saved me a lot of time and phone calls.