You mention : "I have the repeater receive audio hooked to the mic input of the URI (it tried both inputs)" According to the schematic, the only mic input is pin 21. The URI schematic is here: http://dmkeng.com/images/URIx%20Schematic.pdf
Where are you picking up the audio? Is it unsquelched? Preferably direct from the discriminator.
Robert A. Poff Loganville, PA.
"Lieutenant, target the offending power boat and launch photon torpedoes"