I tried restarting the fb in two different ways. Neither of them re-established the connection to dtt or epics.
Please be conscious of what components are doing what. The problem you were experiencing was not "frame builder down". It was "dtt not able to connect to frame builder". Those are potentially completely different things. If the front end status screens show that the frame builder is fine, then it's probably not the frame builder.
Also "epics" has nothing whatsoever to do with any of this. That's a completely different set of stuff, unrelated to DTT or the frame builder.