737 Aux nav power question

[j3cubcapt]

On the Classic B737 (300/500)

The question has come up "What power source does the Aux Nav radio recieve power?"

Senerio....
Capt or F/O is using the Aux Nav radio performing a F.D. or Autopilot approach. At G/S intecept the TR3 Disconnect relay opens, Will the Aux Nav radio loose power?


Thanks for the help!

J3