use the following diagram
-----------------------------------------------
| + - - - |
| B6 B4 |
rear | - + B2 B1 | front
| + - |
| B5 B3 |
| - + + + |
----------------------------------------------
B5+, B6- leads to zero volts when measured to frame. B6+ has 6 volts, B5- has -6 volts.
Weird, hm? I'm going to sit down this weekend and have a long look thru it. Chris