1989 Toyota Pickup alternator/ charge system/ shortage?

Electrical problem
1989 Toyota Pickup 4 cyl Two Wheel Drive Manual

it's not the alternator. We changed it and now it's charge is reading below the norm when started. We think it's a shortage or wire problem. The problem is what or where can we check? We checked the fuse under the hood and in under the dash. Can you give me any and all info on this matter. Going nuts.

thank you