[TR] TR4 Electrical Issue

[Brian Jones]

While I'd like to hold the Prince of Darkness responsible for my  
issue, its far more likely something I have done. I am puzzled, and  
wonder if anyone has a suggestion for resolution.

I reversed polarity on my car, following the set of directions  
available anywhere one might wish to look. However, my car is no  
longer charging.

I have been using the Lucas Fault Diagnosis Service Manual (actually a  
facsimile of same that someone photocopies and sells at some profit on  
ebay).

The step-by-step testing tells me:

The armature circuit is 'almost' in range: 1.1 - 1.2V at 1500 revs  
(should be 1.5 to 3.0V). I put this down to a somewhat tired 45 year- 
old unit.
The field circuit is in range (delivering 2A at about 12V)
The dynamo leads are OK (if having been previously butchered by a PO,  
when the 6" pigtails at the dynamo end of the loom were cut off,  
inexplicably, then poorly reattached).

However, when I come to compensated voltage control, here is where  
things fall down.

The directions for test this are:

Remove and join the A and A1 leads, connect a voltmeter between D and  
earth, and increase the speed to get regulation voltage of about 16 -  
16.5 volts.
I get nothing, nada, nichts.

The diagnosis suggests....
A faulty control box earth, however, the earth lead on terminal E is  
good.
An open circuit shunt winding. If I have an 'open circuit shunt  
winding' what do I need to do to fix it?

I manually closed the coil on the control box (engine off, battery  
connected) and immediately had begun to let the smoke out of the loom,  
on the smaller wire on D that feeds.....the ignition light.

What have I done to cause this failure?

Any and all suggestions welcome. I am tempted to go back to positive  
ground just to see if things right themselves....

Brian
1963 TR4