I have a ATI all in wonder. I don't get any TV signal out of it though. I heard someone say that it was probably because i had a cheap cable connected into it but it isn't just a few feet that is of the cheap cable we ran a cable through the garage to add a cable line in this room. That was about the same quality would we have to replace all of that then...
you sure you set the proper settings?
like NTSC and Cable TV? (and not antenna and PAL)
I tried all the settings and i basically just gave up and put it in my brothers computer since i didn't want to go buy him a new one and i thought about it then unplugged the cable from the modem and i was getting TV signals fine
If you get nothing through it at all, then this will not help. If you get green lines and the picture is distorted, ATI released this info about problems in XP and the MMC (does your brother use XP as well?):
Hope one of them helps.