[X4U] Starts to boot, then black screen

[Crandon David]

Hello Everyone,

Having trouble after upgrading to 10.4 Tiger in a 450MHz G4 AGP  
Graphics mac.

This computer is used with an Apple 20" LCD display purchased about  
2-3 years ago.

It was running 10.2.x, then we upgraded, first a straight upgrade,  
then tried an Archive and Install on the main hard drive, then did an  
Archive and Install on the internal backup hard drive which was a  
clone (over a year old) using Carbon Copy Cloner. We've had the same  
problem in all instances.

After the upgrade, we get a brief grey screen, then it goes black. We  
don't see the spinning little grey clock dial thing or anything else.  
This happens with both internal drives. The firmware is at it's  
latest version. We used Apple's Disk Repair and Repair Permissions at  
all appropriate times. We also ran Diskwarrior several times as well.

The computer will boot properly if we zap the PRAM, but after  
shutting down and rebooting we get the black screen again. We have  
replaced the internal battery and pressed the CUDA button and reset  
the logic board per Apple's Knowledge Base articles.

It boots properly from the Tiger disk and from the OS9 part of the  
system. The backup internal drive booted fine even though the main  
drive had this problem. After upgrading the internal drive we got the  
same problem with it as well.

We've upgraded using Software Update to all the latest stuff,  
however, these problems happened even before we did that.

NEW INFO: Just found out that if, after the screen goes black, we can  
press the power button once, which starts it pulsating as if the  
computer is asleep. Then, after pressing it again, the screen comes  
back on. So it appears that the computer is booting properly, but the  
screen goes black as if it's asleep. But the weird thing is that it  
goes black initially even before the OS loads. Changing the sleep/ 
screen saver settings make no difference.

Anyone?

Thanks,

David