My IMAC G5 First Generation WONT SLEEP by itself

Question

I have more than a year with this amazing machine. About a month ago it only will sleep manually, even when my external HD is off, no printer conected and IDISK not sync. Any help ? I search in the forums but most common trouble seems to be the opposite. Tks in advanced.
imacg5 17 flat screen   Mac OS X (10.4.6)   Mexico, City

Answer 1

iLee,
What you described is for the later iMac models, not the Rev A, which Carlos said he has---and that process you just mentioned is not for resetting the PRAM, but the SMU.
Here is how to reset the PRAM from Apple's support pages:
This document explains how to reset the parameter random access memory (PRAM) and nonvolatile RAM (NVRAM) on Macintosh computers.
Resetting PRAM and NVRAM
1) Shut down the computer.
2) Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
3) Turn on the computer.
4) Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
5) Hold the keys down until the computer restarts and you hear the startup sound for the second time.
6) Release the keys.
Your computer's PRAM and the NVRAM are reset to the default values. The clock settings may be reset to a default date on some models.
Here's the LINK.