I have a 622 and 722 with dish pro LNBs on two dishes pointed at 119 and 129 connected to a dp34 switch and it also does not recognize 129 when I do a switch check. I was able to get it aimed (somehow) and have strong signals, 68 on TP 5,7 and 9 and 84 on 12. The only way that I could watch any channels off 129 was to disconnect the satellite inputs to the dp34, run the switch check and save the change (that were was no satellite signals). Then I unplugged the receivers to reset them, reconnected the 129 input to the dp34 and powered up the receivers. Then they would recognize the 129 satellite on the point dish screen, but still would not recognize it during a switch check. Oddly enough at this point it did bring up the 129 guide and I was able to watch HBO west or the two local Achorage channels on 129. I reconnected the 119 input to the dp34 and ran the switch check again. It recognized the 119 sat, but still did recognize 129. For two days after that the 129 channels remained in the guide and were viewable (even though 129 was not shown on the switch check) but yesterday they disappeared from the guide.
AK Golf, let me know what the dealer finds. It sounds like I may have the same problem.