I have an ATI 4890 connected to a Crescendo TC1600 transcoder connected to a regular CRT TV.
I've used ATOM-15 to create a modified BIOS, and the BIOS flashes fine, but the Windows 7 boot process is still very distorted. I think I can see a diagonal retrace and the screen flickers extremely bad.
Is it possible that my card is not compatible, or that I need modified 15.7 kHz settings?