So it turns out the RF switch onboard the Genesis has a loose connector. If I move the SNES modulator around a little bit when it's plugged in, the picture comes right up. Guess I need to do a little surgery to it. BTW, if anyone has a dead version 1 Genesis, or just the shell I'd be interested in it. This one has some large cracks on the back and I'd like to make it all pretty before I mod it.
Scott