black screen after sleep

[Eolake]

I have a new iMac and a dual 800 G4.
BOTH of them sometime "wake up" after sleep with a black screen. The screen does not wake up.

I thought it might be hardware in the G4, because it had some problems also under OS 9. But now the iMac has shown the same problem once. I use 10.1.4 on both machines.

Any ideas?

 

[IceDogg25]

If it does it on BOTH computers, and you installed OS X on both of them with the same CD, maybe you shpuld try re-installing OS X.

 

[Eolake]

They were not installed from the same CD. The iMac came with OS X on it.

 

[Eolake]

Well, I do use Tinkertool and Key xing on both of them.