Wayne -
Is your friend certain that the system was locked onto the correct [presumably the 101] satellite? One way to check is to see if transponders 4, 12 and 20 have a signal. Those transponders are dead on the 101. If the system is not on the correct satellite and the Datron has a stow feature switch, toggling the stow switch will cause the system to search again for a satellite.
The Datron may NOT need a connection to the RX to lock onto the satellite. Again the Datron will probably search for a satellite and then peak on it. If it is not the correct satellite, a toggle of the stow switch may get the system to search again and the process continue until the correct satellite is found.
I have a Datron 3050 and a Sony RX combination. At least once recently, the Datron locked onto the wrong satellite. Symptom was a 'peaked' message on the TV screen from the Sony RX and no picture. A discussion with a local shop identified the transponder information.
Good luck to your friend.
-- Ray --