[TR] control head

[Gary Nafziger]

Listers,
I started taking apart my tr-3 control head and ran into a problem. 
I can't figure out how to get it apart in order to install new wiring.  I've
taken off the 3 screws on the back which allowed me to remove the bakelite
horn button from the horn button surround.  I see three tabs coming through a
steel plate which are bent over but it looks like it would take much pressure
to bend them straight to remove.  The front has two screws which hold the
copper contacts but it seems they can be turned forever without coming loose
enough to remove.
In short.  Does anyone know of a tech article which might
help in changing the wiring.

thanks

gary n.