Im working on a Mackie Th 12a (thump). The resistor r4 connecting jr2 (xlr jack) to J1 is fried. If youve got the schematic its on the TH-12A AMP SCHEMATIC 0021633-XX-E09-SCH page. Its just a 100 ohm resistor. Does it have a specific function and need to be replaced?? Or can I just run a wire connecting the two solder pads.