Imac Sleep Issues

[Durango Kid]

Have a new (April 05) G5 iMac running 10.4.2. Machine is set to sleep automatically. Occasionally, it will not awake from sleep. On these occasions mouse or key inputs have no effect. Screen is black and cooling fan is sometimes running at high speed. Normal method of recovery is to power down and restart. Rebooting is always successful. Opened service ticket with Apple and have conducted tests suggested with no problems noted. Macine seen by local Apple store where a hardware test was again run and this time failed (video problem). Logic board was replaced. Machine was used several days then original problem recurred.

Programs running when problem occurs: Finder, Safari, Mac mail, Dashboard

USB ports used: KB/Mouse, Printer, and UPS

Last O/S update: July 25

[verma]

Hi - could it be the USB extensions? Does the problem occur without the USB connections (except keyb + mouse)?

[ElDiabloConCaca]

I gotta second that suggestion -- try operating with only the keyboard and mouse attached. USB devices are notorious for causing sleep/startup/shutdown problems.