I thought about that, but it seems to have an extra ground for the field coil, assumed that the white wire would be controlled DC to the field. It is possible it's controlled ground of course. That would cause zero alternator output but not, as far as I know, damage a controlled ground regulator.
After hookup test it: switch ignition to ON, and measure the voltage at the white wire. With the engine not running I figure the battery voltage will be low enough that the field should be full on: if all is well you should have almost battery voltage between white and ground. If not, disconnect the white and measure from it to ground and black (ignition ON again). A switched ground reg will show around a volt from ground and about a volt less than battery voltage to black. To use it you have to rewire the field coil so it gets power on one wire from a black wire, and the white reg wire to the other field wire. Stock reg grounds one field wire with the other one still to the white.
A blown electronic reg will either show zero volts to ground or bat+ if the output device has blown "short", or an indeterminate voltage - floating around depending on your meter - if the output device has blown "open".
