[mikethedruid]

Look at the schematic. one side of the field coil of the speaker, labeled as a blue wire on the SCHEMATIC, goes to the negative terminal of C17 and the center tap of the high voltage secondary of the power transformer, as well as one side of R10. That wire labeled "blue" on the schematic seems to be the red one shown on the wiring DIAGRAM, which goes to the "reproducer terminal board" and from there to the negative side of C17. Trace these wires on the wiring DIAGRAM, and then carefully compare them to the SCHEMATIC, and you will see what I mean. It should become clear then that all these points, the second in terminal on the resistor board with R10, and the black and brown wire and the red (or blue) wire, and the negative side of C17 all are directly connected, and should have virtually no resistance between them. I think part of the confusion comes from the discrepancy between the DIAGRAM which shows a RED wire, and the labeling on the SCHEMATIC which says BLUE. I really never bother worrying about colors much since they are mostly so faded on the wires these days that they all look brown. Instead I just trace where they are going.