by Y-my-R » Fri May 10, 2019 2:27 am
You didn't add anything to the word clock chain anywhere, right? The setup remained the same, but suddenly the sync issues started?
I had a similar issue with one of my d8b's from when I originally got it, that took me forever to figure out. Eventually I noticed that my desk synced to external word clock, when the the last 17-24 I/O card wasn't installed. I swapped cards around between my two desks, and it wasn't the cards... they worked fine in other positions. But something being in that one slot, caused all these sync issues for me.
I left it out, and was able to operate on external sync successfully, sans those 8 inputs/outputs I really would have liked to use. I tried again a few months later, and suddenly it worked. No changes since then. It still works today... like a year later, or so. Just weird behavior.
Have you tried removing ALL the cards except for the clock card and the stock AES/EBU card (I'd even pull the FX cards for a test), and check if it syncs to external then?
Last "captain obvious" thought... you didn't start using your MOTU interface at a sample rate the d8b doesn't support, like 88.2 or 96 kHz? (or lower than 44.1... that's also not supported from what I understand) That would also cause the issue you're describing, but I'm sure you already know that.
Anyway, good luck with pinning this down!