Late 2005 PowerMac G5 with a NVIDIA Quadro FX4500 display question

[andrew678122]

I have always lusted after PowerMac G5s, so recently I bought one off eBay, a nice, clean, Late-2005, 2.3Ghz dual core. So of course I have to tart her up a bit, maxed out the memory, a 2Tb hdd, and a NVIDIA Quadro FX4500 card. I use a 43" Vizio Ultra high def tv as my monitor.
When I first turned it on after replacing the 6600 card with the NVIDIA Quadro FX4500 I thought the card was defective — I got no screen display from either DVI — I mucked around for a bit but couldn't find anything wrong. Then I decided to share the screen with my iMac, and the G5 running OSX 10.5.8 was seeing the FX4500, but for some reason it wasn't displaying on the 43" Vizio. I switched DVIs and when I couldn't think of anything else to try I connected an old monitor to the FX4500 and I got the G5s display, and when I did that the Vizio tv also got its display working. But I don't need the old monitor plugged in, just connected to the FX4500 with a DVI cable.

It seems like I have to have that old monitor connected to the FX4500 or the display on the Visio blanks out. I would really like to eliminate that crappy old monitor, anyone know what the problem is and how to fix it?

 

[SuperKerem]

You need to make sure the card is the G5 variant. There was also a Mac Pro variant and a PC variant. If you have one of these, you need to flash your card with the G5-compatible firmware.

This might be helpful:
https://forums.macrumors.com/threads/flashing-a-quadro-fx-4500-for-g5-compatibility.1991875/

 

[VanneDC]

if it was an unflashed PC card, there would be zero output from either port, period.
Strange.

 

[andrew678122]

You need to make sure the card is the G5 variant. There was also a Mac Pro variant and a PC variant. If you have one of these, you need to flash your card with the G5-compatible firmware.

This might be helpful:
https://forums.macrumors.com/threads/flashing-a-quadro-fx-4500-for-g5-compatibility.1991875/

The card works so it doesn't need flashing.

It's almost as though there is some handshaking between the FX 4500 and the monitor, the 'real' monitor has it but the Visio doesn't, like just a pin pulled low...