Where is the voltage regulator located in a 1988 E-150 van? Is it internal or external?

Thanks

 

I think I have a voltage regulator thats blown. One of them lets battery power through one way, but doesnt let ac power through the other way. I just want to identify the IC so I can get the datasheet and test it some more.Here are the markings4890AK?L57A Its 8 pins, 4 on each side. I cant make out the manufacture logo.

 

The voltage regulator should be between the power supply and everything else. If you were to wire the regulator after the controller it would try to keep the voltage to the car constant The regulator itself only uses a tiny amount of power, it is the load that uses power. Actually a number of our tracks use diodes and we have never had one burn out. I tend to use 6 amp diodes, it does not hurt to have a circuit breaker for each lane. The regulators are supposed to have built in current limiting, but I would not bet my life on that.