Classic/Antique Car Repair: voltage regulator, dc generators, brown wires

Question
New regulator just installed will not charge.  Check generator, wires, etc. All Okay.  Put in old regulator (original with 71 Midget)and it works okay.  Difference between old and new box is that the F (field)spade is open when contact is made with other spades (not B)but in old original box all spades are closed, short as volt meters says.  Old charges battery, new does not.  What's up?  I also have a new regulator that I purchased in l971;  it also has an open F terminal.  Been driving MGs for 40 yrs.  First time with this problem.  Thanks.  

Answer
Hi Ed,
Please clarify what you mean "Spade is Open" or "Closed". Do you mean nothing is connected to it? This is a 71 Mk IV Midget with a generator not an alternator correct?
The terminal marking on the regulator are "A1"-"A"-"F"-"D"-"E" The brown wires go to "A1 & A" which are battery powered all the time. The "F" field wire is a small 14 gauge brown with a green tracer. "D" is brown with a Yellow tracer and is the 12 gauge wire going to the generator armature. "E" is ground and is black. Almost all British car regulators for the DC generators are wired this way.
Let me know.
Howard