Rodomania

I bit the bullet and made an account, I don't know if this is the right place to post this. I'm having charging issues currently, as of a week ago the car was running great. It's a 77' 280z, currently the battery isn't charging and my fuel gauge fuse blows in the first stage. I've replaced the Alternator from Autozone, changed the Voltage regulator from MSA, also the fusible links also from MSA but it's still not charging. The first video is me turning the car on it stays at 12v constantly and when I turn it on it dips a bit then back to 12v and my charge light stays on even throughout the drive, the picture of the fuse is the blown fuse and that happens usually after the first stage of the key turn, and its the only fuse thats burns, the new alternator has proper tension, I'm curious what the P is on the wiring. I've had the battery tested and everyplace says it's good it just dies. I'm stumped please help!!?? 20190518_085013.mp4