Some users have reported a lack of digital signal over the AES output connection into their external equipment. In circumstances where measurements were able to be taken, typically the level reads around -138dBFS and changing levels on the console makes no difference.
This has now been replicated successfully by SSL, and is due to occasional instances of Back-Power being fed into the AES inputs from certain external hardware during the Boot-Up Sequence of Matrix, which then causes the AES outputs to fail.
1). By making sure there is no external AES hardware connected until after the Matrix has Booted, this problem will not occur.
2). Another method would be to make sure all external AES connected hardware is left switched off until after the Matrix has Booted. Either way will work but this method will alleviate the need to physically disconnect it.