Here is my CX2600A. Purchased with about 40 games at a garage sale for $5 about 10 years ago.
I recently got a new RCA ----> RF adapter and the quality is good. I was using the Radio Shack TV/Game switch box. Garbage! Get this, much better! Of course it might not be as sharp as the Composite Video mod, but I think it's good! And my LCD doesn't like Composite anyways, RF tends to look better actually.
And the Genesis 6-button pad is THE best Atari controller ever! Except of course the Genesis Arcade Stick.