Q: G5 chimes on startup then displays black screen

Thank you for your reply.

It has two internal hard drives and neither of them show up in target disk when connecting to another mac. In fact none of the usual troubleshooting keyboard commands work either such safe boot.

There is one LED that lights up when I take off the clear plastic deflector to gain access but on replacing the deflector, the LED goes back off again. Apart from that, I can't see any of the LED lights, unless hidden.

Yes, just lights up as if normal.

I have a Powerbook G4, but don't have the other stuff. BTW, that LED that comes on, on the edge of the logic board is a DS8, just in case it is significant. I am wondering if it is not the graphics card, is it possible the whole logic board might need replacing? If that's the case i might be better off just buying another used G5 and transfer the internal drives to that?

True, do you think its worth replacing the graphics card though just to make sure? I mean it might not work but then at least I'll know its probably something not worth repairing (i.e. replacing the entire logic board).

Something strange has happened. The computer has started up on its own several times and each time I had to switch it off because of the racing fans. Then after a few times I got the apple logo on the screen. Booted up again and the screen came on as normal and seems to be working okay apart from an occasional flash from the green light on the apple monitor. Very strange. And I was going to ask you what the racing fans meant, and if the hard drive would start up as normal in a different machine, but maybe that doesn't matter now. What is going on with this G5 man?

Thanks for the link. Things have gone from bad to worse though now. Having shut the computer down, when I came back to boot it up again I found that the startup chime had gone and back to the black screen. I will try and remove the lower processor when I have the correct tool (its a 1.8 GHz Dual) they in the manuel that it can still work with just the top processor running. Aside from that I think I will buy an Identical model I've seen for sale. Do you think if I transfer the hard drive from the old to the new machine, it will start up as normal?