False alarm - the mistake was mine. Looking at the schematic diagram, the AI/Dewhite board, D000316, accepts the inputs from the DAC on the P2 connector. While restoring the connections at 1Y2, I had plugged the outputs of the DAC interface board into the P1 connectors of the AI boards. Having rectified this problem, I am now able to move the beam on the AS camera in both PIT and YAW using TT1 or TT2. So to zero-th order, this subsystem appears to work. A more in-depth analysis of the angular stability of the TTs can only be done once we re-align the arms and lock some cavities.