So I went back to the store where I had purchased the Channel F that I took back a few years ago. I asked if they still had it. Surprise! They did. So I rebought it. And this time I intend to keep it. Even though it has some problems. First off, the only game I can access on cart #1 is doodle. When you turn on the game, you have to press 3 as you turn it on, or else the "G?" message will flash on screen for about a second before it switches to the built-in game. Even that has problems. It keeps switching messages between "S?" and "M?" Pressing any button does nothing except make the letter not flash.
So my guess is that something is wrong with the 1-4 keys. The reset button works, though, which is odd. Why it but not 1-4? Oh, and the controller ports work, because I tested them with Doodle and they work fine. I bought cart #9 on eBay and it should come late next week.
I resumed work on Killer Snake. This part was getting the timer to work. It took multiple tries and hours and work sessions, but I finally did it. The game immediately starts, though. I think I'll keep it that way so if I ever finish it and want to release it on a cartridge, I would be able to play it. I am interested in the Pac-Man Channel F game and I wonder if I could play it. I bet I could if it immediately starts. Or do you have to press a button first?
I wish someone could help me diagnose and fix my Channel F. I started a thread in the classic gaming forums but nobody has replied yet.