Isuzu: 1987 Isuzu pup, isuzu pup, proplem

I have a 1987 isuzu pup. It keeps on blowing the fuse for the voltage regulator. If i put a new fuse in the truck will start but after 5 minutes it blows the fuse again. I have replaced the regulator but I still get the same proplem.
Thank you

Voltage regul;ators are famous for being bad from the get go. replace it again, check your negative wires very closely and all connections. 90% of the time it is your negative connections that do the damage. try that first and write back. ThaT SHOULD WORK.