So I feel like a dope over this, but maybe it will help someone if I talk it out.
A few months ago, I picked up a CC cabinet from Craigslist that came from a fellow KLOV member. When I bought it, I vaguely remembered hearing something about a "free play" mode, but I did not look into it during the purchase. I simply assumed it had a kit installed or a hacked ROM set and I was just very excited to get to take this game home.
I had been enjoying the free play setup but started to wonder why there was no attract mode. After some searching (using the advanced search feature

), I found this thread, which seemed like it might explain what I had... possibly the the V4 Free Play Hack. Howver that link is dead so I have not been able to compare it to what I see.
I decided to investigate. The manual mentions on page 2-4, under Coin Value:
That line did not make much sense to me, but I figured it was worth checking out. Maybe it would explain how my game was setup. I decided to enter self-test mode. I flipped the test switch, and nothing happened. That seemed odd. I began to assume that maybe this was a result of a hacked ROM set.
I removed the board. (The EMI shield made that a fun experience.) Once it was out, I was surprised to see a very clean, factory-looking board and eprom set, with no signs of modification. I dumped the ROMs and compared them against MAME. To my surprise, they matched the ccastle2 ROM set... not V4 and no hacks. That left me wondering how I was getting free play.
Upon closer inspection, I noticed that the self-test toggle switch had the two wire connections on opposite sides at the top of the six terminals. This did not look like my other Atari games, so I repositioned the wires to match the normal layout. After doing that, I was finally able to enter test mode.
Inside the Game Options Menu, I found the Coin Value setting, as described in the manual. It was set to "Free Play" I changed it back to one credit, switched out of test mode, and a similar looking screen appeared, but this time it said 0 credits. After a short wait, the game entered attract mode.
So after all this, I have the "for game demonstrations" free play and didn't realize it because of a miswired self test switch. I am probably missing something else with this setup but now I am really curious why a free play hack exists if the game already includes a "free play" option?
This was a good learning experience howver it was a huge time sink. Anyway, maybe this post will help someone else avoid a goose chase