The DA78HR is known to have problems clocking to incoming word clock from the d8b. The signal is apparently too hot for the DA78HR. Here's how to remedy this problem:

1. Use the Dio8 card's Word Clock out -> NOT the d8b's Clock i/o card.
2. On the DA78HR's word clock IN, connect a BNC connector:
(a) Connect word clock from the d8b (Dio8) to one side of the T-connector.
(b) Connect a 75 Ohm BNC terminator to the other side of the T-connector.

( 3. the d8b's clock should be set to internal. The DA78HR's clock should be set to WORD)