This past week I received a hint that I wanted to pass on: when installing the new Smart Alternator
Regulator make sure to FULLY remove any of the old 'stuff'' attached to the alternator that might have been needed by your old regulator. Things like boot-strap diodes / resistors (including Dash lamps) - make connections instead as noted in the documentation.
And be on the look out for hidden resistors. One person found a large 270 ohm 5W resistor attached from the old D+ terminal (no longer used) to GND. Originally intended to help drive the dash lamp and also provide a minimum load to keep the alternator driven tach running, this extra phantom load played havoc with the Smart Alternator Regulators attempt to stabilize things with its own tachometer mode turned on.
So, pull out the extra stuff - you have been warned!