Playchoice 10 and NES Cartridge Musings

So I'm well on my way to building my NES adaptor for PC10. I've bought a sacrificial NES for the cart connector, and I'll chop up the original motherboard for something to solder to.

I plan to likewise sacrifice a PC10 cart (Pro Wrestling, I suppose) since I have no idea where in the world one would get those connectors. I'll leave the security chip on the cart and wired, and cut the remainder of the traces - it should work without BIOS modification.

One weird thing I ran into mapping it out, is the presence of a 21.47727mhz clock signal on the 72 pin NES connector, which doesn't exist on the 60 pin famicom, nor on the PC10. This is strange, and I've been puzzling over what it could possibly be for.

My theories boil down to this: it's likely used by the CIC lockout chip, which is only present in NES. I thought maybe for expansion, but then why isn't it present on the expansion port?

Another hurdle in NES->PC10 will be the lack of player 2 start/select buttons. I've solved this, I plan to attach a fully intact NES control port assembly to the board, I've located where to solder it in, I'll draw up a schematic one day maybe. The only game I can think of that requires player 2 to be able to hit start is Battletoads, but that's surely a game worth playing on a real arcade machine.

My plan is to build a new control panel with two brand new NES Advantage sticks. I bought them years ago, and have never used them. They still have protective plastic film and everything.

I still haven't thought what I want to do for light gun games. I could always plug in a zapper, but I want to hardwire a holstered PC10/VS lightgun, probably with a switch next to the cartridge slot.

Also, the countdown timer is installed. It took me forever to crimp on all those tiny pins and get the ring working, but there it is. This is another motivation for not wanting to use a hacked BIOS, I don't want it forced into free play mode - I like the idea of timed NES challenges.

I also found this site, which has some cool NES hacks, most notably his VS-in-a-NES box. His code to remap the color pallette for VS Super Mario is exactly what I was looking to do to remap VS Duck Hunt's pallete to work with VS Super Mario. My dream of a arcade version of a VS Super Mario Bros / Duck Hunt is that much closer. (for those who dont know, arcade Super Mario is much harder with different levels, and in arcade Duck Hunt, YOU CAN SHOOT THAT SMUG DOG!)

But I'm way too tired to do anything about it now.