Screen goes black after startup

Try Replacing your GPU, Clean the contacts of the card, Change the slots, this would be the first step towards the repair,

And if still doesn't work try re installing your OS

Message me back if you still face any problem

I have the same problem on my Power Mac G5 2.5 ghz DP Quad.

I have changed the video card, not the video card. That has been tested.

When I power on the computer always chimes.

When I have no hard drive cables plugged in I get video, 99%.

Sometimes I have to reset the Power Management, unplug, press reset, remove battery, power on, turn off

then insert battery and power on again.

I am thinking maybe the cables.

The worse scenario would be to have to replace the processor or the logic board.

One successful time with the hard drive plugged in I got video for about 5 min.

Then the video went away. I am going to test all the cables first.

I am beginning to think the processor.

If I boot into safe mode, I can use the G5 with limited functionality due to safe mode; BUT everything works in safe mode. I get video, audio, I can manage files etc. It’s only when I boot normally, I hear the chime, I get to the desktop, but seconds later, the screen goes black, and monitor shuts off indicating no signal going to the monitor. Once again, if I boot into safe mode, everyworks. Really baffled, not finding much help online either.