What channels have no audio? Some channels are
AC3 and cannot be processed by the BEC receiver. Other channels sometimes require you to switch between stereo/left/right -- use the AUDIO button on the remote to change modes. If you want to change the PID data manually you have to do this throught the TRANSPONDER SETUP menu, fifth line down on the TRANSPONDER SETUP menu. Its on page 20-21 of the manual but I guess you don't have one...
kat