HDX: HD I/O's can't be found

[ThosSounds]

Hi all,

Wondering if anyone has any insight on this one. I'm attempting to move my setup into a new Mac mini with a Sonnet 3 slot HDX model chassis. I've gotten as far as the Mac recognizing the chassis is there and that there is a PCI card in it. Pro Tool Ultimate will let me select HDX as a playback engine, but when I do a message pops up that Pro Tools is unable to find any audio interfaces. I've reattached cables, power cycled the interfaces.. but it won't even let me click "ok" to rescan. I've un-installed and reinstalled the HD Driver, reset P-RAM.

This is a big jump upgrade for me, going from a 2010 Mac Pro running Mac OS 10.13 to this Mac mini running 10.15. I'm wondering if maybe there's a firmware update for the HD I/Os or something

Full specs are:
Mac mini (2018) 3.2GHz 6 core i7
64GB RAM 2667 MHZ
Mac OS 10.15.6
1 TB internal SSD
Pro Tools Ultimate 2020.9.1
HD Driver 2020.9.0
1 HDX card
Sonnet Echo Express III-D Thunderbolt 3 HDX edition (connected with their Thunderbolt 3 to Thunderbolt 3 cable).
Two Avid HD I/O's, the first running 16x16 analog, the second 8x8 analog and 8x8 digital.

Thanks for any thoughts!
Tom

[tech_guy]

That's odd, have you tried swapping out the digi-link cable? How about swapping the order of the HD I/Os? Are they recognised in Digi-test? Does the power ring go from orange to green once booted?

[albee1952]

And, test each IO box alone(no connections to the second one).