If I were the technician, I would bring out an old non DirecTV +plus receiver, a 22 khz tone generator, a 22 Khz tone switch and and two standard 18 inch dishes on portable mounts.
Then, I would set up the receiver directly for 101 connected to a dish at 101.
Then, set up the receiver with the 22 Khz tone generator in line with a second dish at 119.
If both of these works, then I'd set up the 22 Khz switch with the tone generator between it and the receiver and the switch and the switch to each dish at 101 and 119.
If this set up works, I would then try out your receiver without the 22Khz tone generator in line. If the receiver works, you have verified that it works.
Then, using barrel connectors and the highest quality coax with good connectors like Snap-N-Seal, I would then run the receiver's line through one coax in your install at a time through the verified test setup.
If go through this test with everything controlled excepting the one component that you are testing, you will find the offending part.
This is time consuming, but given the time that you've already spent and the complications in the problem, it is the only definitive method.