Last week I got a Datapath E1 capture card, so I can get high quality video captures from old game consoles and computers. So far it has exceeded by expectations in accepting and capturing the video output from a Quadra 630, Power Mac 7200, and Powerbook G4 Aluminum (well aside from the high amount of video noise from the Quadra, that thing is due for a recap). There is one system that has given me trouble with this capture card, my 450 Mhz Sawtooth G4. This Power Mac has an Nvidia Geforce 2 MX Twinview card that was pulled from a later G4. It usually works great, but if I plug the video output with either VGA or DVI (with ADC to DVI adapter) into the Datapath card, nothing shows up in the output regardless of output port or OS (OS9 and OSX Tiger). This isn't quite a cut and dry "it doesn't work" case, as there are some weird issues when the GPU is connected to the Datapath. Sometimes it just won't boot, I can tell because it powers on without any activity noises from the hard drive. I even tried connecting a monitor to the second video output port, this being a Twinview card and all, but there wasn't video output on the monitor when the computer is also plugged into the Datapath. I can only assume that the Nvidia card is throwing a massive fit whenever it's connected to the Datapath capture card. So I am not sure what to do here.
Now I also have an ATI Radeon 9000, which also appears to be an OEM card pulled from a later G4. I got this card last year, but I have never gotten a video output at all with computer monitors. Aside from one occasion that it was able to boot into Mac OS 9 while it gave a video output. It was able to run Quake 3, and it was beautiful. To this day, I am not sure what got the ATI card to function on the Sawtooth on that one occasion. I have not been able to recreate it, and it still doesn't work with the Datapath.
After these two cases, I suspect that my G4 has some slight issues with graphics cards. I have tried resetting the NVRAM in both cases, but no results. Is there anything else I can try? I do happen to have a non-functional G4 Cube with a Rage 128, though I am not quite sure about extracting the card and fitting it into the Sawtooth.