Here is some info for those of you that may find it interesting to see what's inside the sealed black box single phase voltage regulator. The business end of the regulator is made up of 6 beefy semi conductors. These are what do 99% of the work, generate 99% of the heat and probably go bad 75% (my guess) of the time. These are the components you are testing with the service manual meter tests (bleed back test etc). The interesting thing to note is that the single phase regulators are in-fact shunt regulators (see shunt semi's S4035's clamping stator) but the late model 3 phase regulators are not. Surprisingly my 2009 service manual has a mistake which says my 3 phase regulator is "shunt" when it is not. Also note that not 1 single integrated circuit was used in the complete design. All discrete components. Also note (schematic) the dangerous issues that "could" arise if you happen to be running short of good luck. Almost any combo of failed semi's will always result in a dead short across your stator. No wonder they go out in pairs! My Thanks goes out to TQuentin1 for boxing up,,shipping & supplying me with a pair of DOA single phase Genuine HD regulators as organ donors. Thank you TQ!