Just a couple of items of note here. 1) Your bike was probably built in the fall of 79 as one of the first 1980 models. 2) What kinda shape is your battery? Have you charged it off the bike and what voltage do you get with it fully charged disconnected from the bike? You should have full battery voltage on one of the brushes. 3) Check both the stator and charge coil resistances with a good VOM and compare specs. 4) Not sure which fuse box you have but the glass fuse boxes are notorious for crumbling and falling apart. 5) To test the key switch, jumper from red to brown on the key switch connector in the headlight bucket and see what voltage you get on the brushes. Keep us posted.