If it works on the Mac IIsi, it should work with the Mac II. Go back and get it working with the IIsi and then switch it to the Mac II. Make sure the video card is tight on the board, they do get loose on the socket.

If not, it's time to get the video card recapped. Just like the Mobo. But since the Mac II starts up, the culprit looks like an iffy video card. Though recapping the video card is the same as the Mobo, I have not seen anyone doing it. I think Uniserver might do it - ask him. Depending on the video card, it is usually about 10 caps to replace.