Good morning everybody

Pro Pattern, if you check the following page on Troy's web site you will see that when too much power goes through a regulator then it usualy fails and gives 8.4V and not 0V:

http://www.troybuiltmodels.com/Regulators.htm

Also, there is no need to have a load on the regulator to measure the correct voltage. It makes almost no difference. You need a load to measure the voltage of the battery to know its status. Unfortunately if you measure 8.3V at the end that goes to the receiver its preaty certain that you need a new regulator.

Eddie, the extra lead is for measuring the actual battery voltage (under load) and also for charging the battery without disconnecting it. I am not familiar with the Radio South switch but I guess all regulators are similar.

Serafim