They were faulty indeed and replaced.
This issue however is caused by some clock issues. Input is fine, digital output ( AES ) and analog output are muted.
Replacing the analog io card makes the unit work like a charm.
With the broken card however, the machine was working, but with some very loud audible clicks in the audio ( possible some or one sample(s) wide ).
And suddenly no audio at all anymore. Just plain white noise ( output ) when the machine is switched on. The white noise dissapears after 1 or 2 seconds.
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