Battle Chess by Interplay used a manual look up for it’s copy protection.
Here is the Off Disk Copy Protection sheet: Battle_Chess.txt
Grave Yard is a different kind of football game.
For the disk copy protection you are asked for a STAT out of the manual.
Commodore 64 Cartridge Port Repair.
My main C64 would NOT play a number of cartridges, especially Atarisoft cartridges like Centipede, Dig-Dug, Robotron and Pac-Man. So I filmed the process of replacing the port. Hope the video can help someone else with cartridge problems.
Here is an Accolade Copier I found on the back of my 21-Second Backup disk
GEOS – Leroy Cheatsheet
This is a nice one with a ton of info for you.
The PDF is here: Geos-card
The Jpeg is below: