R143 is the LARGE TAN Resistor between V9 and V10. R139 is to the left of R143 and sitting on the green block cap. This is the normal location for them. R139 is striped BRN RED RED Silver. Tube. Dave G. has fabricated a special jig for the FISHER MPX units to align them. They were built and aligned on their own line, and then installed in it's tuner, so it's possible to align them out of the tuner/receiver. So someone with a flaky MPX can remove the MPX unit from the tuner or Receiver, send it to him, it gets aligned on a FISHER 300 MPX alignment unit, and shipped back. You might be interested in some of the stickies, that pertain to the Hx and problems with these. There is a sub list called Reference Technical threads that has more than a few threads pertaining to the MPX modules.